RE: Monitoring Random ESD events
Brent, Please contact Trek, they have a very nice product that measures and logs ESD events. It measures voltage (on contact) but it has ports for external sensors. The product has been designed for Hewlett Packard a few years ago. David Pommerenke From: brent.dew...@us.datex-ohmeda.com [mailto:brent.dew...@us.datex-ohmeda.com] Sent: Tuesday, July 08, 2003 5:38 PM To: Eric Penne Cc: emc-p...@majordomo.ieee.org; owner-emc-p...@majordomo.ieee.org Subject: Re: Monitoring Random ESD events If you can get near the sensors (1 inch), 3M makes a static field meter. Their Model 718 is a non-contact device and has an analog output proportional to the field for logging. Best of luck, Brent DeWitt Eric Penne epe...@ieee.org To: emc-p...@majordomo.ieee.org Sent by: cc: owner-emc-pstc@majordom Subject: Monitoring Random ESD events o.ieee.org 08-07-03 02:38 PM Please respond to Eric Penne I'm pretty new to the EMC scene and I need to monitor a product to see what kind of ESD events it generates on its own. The customer wants me to attach my oscope to their sensors and see what kind of ESD voltages their sensors see in daily operation. I know that I don't want to directly connect the oscope to the sensors while the machine is running. I was trying to figure out a way to isolate the signals on the sensors from the oscope but still get a value that is useful. I was thinking of some sort of current loop around the sensor wires. How would I correlate the current loop measurement to an ESD voltage? I'm probably not providing enough information but I'm not really sure what information will be needed. Thank you, Eric Penne epe...@ieee.org This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: ESD Problem
My hand is up. David Pommerenke From: Luke Turnbull [mailto:luke.turnb...@trw.com] Sent: Tuesday, May 27, 2003 8:23 AM To: emc-p...@ieee.org Subject: ESD Problem Would the gentleman who is on the 61000-4-2 committee please put his hand up? Thanks, Luke Turnbull This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: emc_p...@symbol.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: HV relay
Dave, The voltage drop accoss a relay (same is true for an ESD protection spark gap, or a non-linear polymer ESD protector) contact after it sparked over is often in the range of 25 V (I have no data on mecury wetted relays) or so for currents in the 1-20A range. It is very difficult to measure it, as the step response of the measurement system must settle extremly fast (2 ns after a 1000 V drop you want to measure with +/-5 V accuracy). The physics of the 25 V are not well understood in my opinion. Obviously, it cannot be 0 V, as some field is needed to drive the charge carriers over the gap. For larger current arcs, over larger distances, at later times (microseconds) the situation of Anode layer and Cathode layer etc. is better understood. If anyone knows a theory why there is about 25 V drop for a small distance, medium current spark gap, please let me know. David Pommerenke University Missouri Rolla -Original Message- From: drcuthb...@micron.com [mailto:drcuthb...@micron.com] Sent: Wed 5/14/2003 5:38 PM To: Pommerenke, David; drcuthb...@micron.com; emc-p...@majordomo.ieee.org Cc: Subject: RE: HV relay David, thanks for the great information! This is the theory we're subscribing to. The arc mechanism takes place at the negative electrode. I just tested a mercury wetted coaxial relay, from 0 to 500 volts and it exhibits a 10 volt drop across the arc. It is not polarity sensitive, which surprised me a bit. I expected a difference between electron emission from the reed (tungsten?) and from the mercury pool. I guess that in this case the mercury arc dominates things. I'll see what happens if I heat the relay to raise the mercury pressure and ion mobility. I will order the SF-6 filled relay that you recommend and give it a try. I might experiment with contacts immersed in FC-40. The runt pulses are not a show stopper but are an annoyance. Dave Cuthbert Micron Technology -Original Message- From: Pommerenke, David [mailto:davi...@umr.edu] Sent: Wednesday, May 14, 2003 3:48 PM To: drcuthb...@micron.com; emc-p...@majordomo.ieee.org Subject: RE: HV relay Dear Dave, You are working on a difficult issue. Every HV relay will breakdown before the contacts touch. The reason is as follows: When the contacts come closer the surface field strength Increases. The field strength will increase so much, such that the field emission current reaches current densities sufficient to melt the surface material. This melting surface material will create a conductive path. The process is called Explosive Electron Emission and takes place in Vacuum and in gas filled relays. Now there are some particularities for gas filled relays. i the pressure of the gas is not that high, the field eission or other processes might initiate a gas breakdown. At least for high pressure relays and for Vacuum relays, nrmally the breakdown is caused by surface explosions. Now, after the initial breakdown and some current the arc might extinguish again. This will show up as bouncing in the current pulse and times of 50 to a few hundred nanoseconds are typically. There are many influencing factors, some of them are: - Speed of approach of the electrodes - External current - Gas filling - Surface materials After the contact meet, the contacts might bounce, leading to interruptions or changes in the current in the us or ms range. Regarding the Vacuum breakdown strength. There is no 'Vacuum breakdown, it is all a surface process. In general, I suggest to think about using N2-SF6 filled relays. The HC-5 from Kilovac is a good choice up to about 10 kV, if mounted in epoxy. You can reduce the drive current or shape the drive current to reduce the problem of bouncing. David Pommerenke University Missouri Rolla -Original Message- From: drcuthb...@micron.com [mailto:drcuthb...@micron.com] Sent: Wednesday, May 14, 2003 11:09 AM To: emc-p...@majordomo.ieee.org Subject: HV relay I'm designing some ESD test equipment for in-house use and need some suggestions on relays. I am experimenting with a 5 kV COTO vacuum relay and notice that I get some runt pulses. It appears that the contacts arc before they touch and then the arc extinguishes after 50 ns and then reignites. About half the time
RE: HV relay
Dear Dave, You are working on a difficult issue. Every HV relay will breakdown before the contacts touch. The reason is as follows: When the contacts come closer the surface field strength Increases. The field strength will increase so much, such that the field emission current reaches current densities sufficient to melt the surface material. This melting surface material will create a conductive path. The process is called Explosive Electron Emission and takes place in Vacuum and in gas filled relays. Now there are some particularities for gas filled relays. i the pressure of the gas is not that high, the field eission or other processes might initiate a gas breakdown. At least for high pressure relays and for Vacuum relays, nrmally the breakdown is caused by surface explosions. Now, after the initial breakdown and some current the arc might extinguish again. This will show up as bouncing in the current pulse and times of 50 to a few hundred nanoseconds are typically. There are many influencing factors, some of them are: - Speed of approach of the electrodes - External current - Gas filling - Surface materials After the contact meet, the contacts might bounce, leading to interruptions or changes in the current in the us or ms range. Regarding the Vacuum breakdown strength. There is no 'Vacuum breakdown, it is all a surface process. In general, I suggest to think about using N2-SF6 filled relays. The HC-5 from Kilovac is a good choice up to about 10 kV, if mounted in epoxy. You can reduce the drive current or shape the drive current to reduce the problem of bouncing. David Pommerenke University Missouri Rolla From: drcuthb...@micron.com [mailto:drcuthb...@micron.com] Sent: Wednesday, May 14, 2003 11:09 AM To: emc-p...@majordomo.ieee.org Subject: HV relay I'm designing some ESD test equipment for in-house use and need some suggestions on relays. I am experimenting with a 5 kV COTO vacuum relay and notice that I get some runt pulses. It appears that the contacts arc before they touch and then the arc extinguishes after 50 ns and then reignites. About half the time it the contacts appear to make physical contact before arcing. If I remember correctly, the strength of a hard vacuum is 200 kV/cm. So, at 5 kV the contacts can arc when they are 25 microns apart (actually further apart due to field enhancement). Are there any vacuum relays that do not exhibit runt pulses? Dave Cuthbert Micron Technology This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Monotonic and Non-monotonic EUT response in ESD testing
Dear Group,
There has been a discussion in EMC-PSTC on EUT response to different ESD
test voltage levels. Let me explain whay I understand about this
problem:
An EUT may respond monotonic: More stress, never reduces the EUT
response.
or
An EUT may show a non-monotonic response: It fails at a lower level,
but passes at a higher level.
To understand the possible reasons one needs to needs to distinguish
between effects
- of the source (excitation)
- of ESD protection networks
- of the circuit (except the ESD protection networks).
1) Is the excitation function linear and/or monotonic?
==
For contact mode the current waveform is (nearly) proportional to
the voltage. One can reasonable assume that the stress is
proportional
to voltage.
For air discharge mode, the average rise time is shorter for lower
Voltages. So an EUT that responses to rise time (or high frequency,
content or dI/dt) may fail at a lower voltage but pass at a higher
voltage.
Of course, EUTs can react to: Energy, Charge, current, Current
derivative,
Electrostatic fields, High-impedance fields, Magnetic fields, high
frequency ( 1GHz) components of fields etc. So an ESD test is
actually a test to many different physical phenomena.
Looking at each stress parameter of real ESD and of Air discharge ESD we
see:
Energy - proportional to voltage^2 = Monotonic
Charge - proportional to voltage = Monotonic
Electrostatic field - proportional to voltage = Monotonic
Low freq content of the current - Proportional to voltage = Monotonic.
Low freq mag field of current - Proportional to voltage = Monotonic
Rise time of current - in AVERAGE: increases with voltage =
Non-Monotonic
High Freqs of fields - in AVERAGE: decrease with voltage =
Non-Monotonic
Peak current - in AVERAGE: Increases with voltage,
but not linear = non linear,
but
Monotonic
= Conclusion #1: For air discharge, lower levels always need
to be tested, even if the EUT has a monotonic
electrical stress - EUT reaction response.
2) Are ESD protection networks linear or at least monotonic?
a) RC network as low pass filter (or other low pass filters).
They are linear and of course monotonic.
b) Clamping diodes, Varistors etc.
They are non-linear, but monotonic. So they would not cause
a fail at lower levels, but a pass at higher levels.
c) Snap-back devices (e.g., Spark gaps, Some transistor circuits)
They can cause a pass at high levels (snap back occurs) but
a fail at lower levels (not enough excitation to snap-back).
3) Is the circuit response monotonic?
=
In most cases: Yes. Meaning if the stress is increased, the
effect is not reduced. But there are exceptions. I will name
an example:
a) An ESD causes a pulse on a reset line (assume contact mode,
meaning linear excitation). For lower voltages, the pulse
is large enough to reset some ICs, but not all that are on
the reset tree. Consequence: The EUT will get stuck in
an incomplete reset. For higher voltages, the EUT would
perform a full reset that might lead to a pass in the test
(depending on the EUT of course).
= Conclusion #2: For discharges to grounded areas (e.g., chassis)
These discharges usually lead to soft-errors. ESD-
protection circuits are normally either low pass
filters (linear anyway) or overvoltage protection
devices. The later may have snap-back. But discharges
to the chassis usually do not trigger snap-back
devices, as they are there to protect against direct
discharges to PINs.
Non-monotonic responses in contact mode testing
are rare, but they may occur. In most contact
mode testing an increase of the stress (=voltage)
will
not reduce the EUT response.
= Conclusion #3: For discharges to PINs or other non-grounded areas
(e.g.,
an LED, such that the spark hits the board)
snap-back
devices may trigger leading to a non-monotonic EUT
response.
Now to access the overall risk to the customer, one needs to take into
consideration what the risk of low voltage ESD is relative to high
voltage ESD.
Very roughly one can say:
Lets say, an EUT will see 1000 ESDs up to 3000 V a year. Then we
can roughly say: It will see 100 ESDs from 3000 - 6000 V
It will see 10 ESDs from 6000 - 9000V
RE: ESD gun verification
Dear Chris, Why not a Spectrum Analyzer? For none-traceble verification it is a very good tool. For tracable measurements there are the following problems: - The amplitude uncertainty is about +/- 1.5 dB =about 15 % - The pulse is repeated let's say 20 times a second, but the pulse is only 100 ns wide. So the requirements for the linearity of the mixer is very high. David Pommerenke From: Chris Maxwell [mailto:chris.maxw...@nettest.com] Sent: Friday, May 09, 2003 7:28 AM To: Pommerenke, David; John Woodgate; emc-p...@majordomo.ieee.org Subject: RE: ESD gun verification One question that struck me is: Why isn't a spectrum analyzer used to verify the waveform? Most labs don't have a 4Ghz oscilloscope; but they almost all have a 10Ghz spectrum analyzer. It seems that the spectrum of the waveform should be just as traceable and repeatable as the waveform itself. From my own experience, I use this method to quickly verify our EFT generator in our own lab (although I'm just a manufacturer, not a third party lab). We have the EFT generator calibrated yearly; and whenever I use it, I turn on the spectrum analyzer and read the spectrum just to make sure that it's working. Chris Maxwell | Design Engineer - Optical Division email chris.maxw...@nettest.com | dir +1 315 266 5128 | fax +1 315 797 8024 NetTest | 6 Rhoads Drive, Utica, NY 13502 | USA web www.nettest.com | tel +1 315 797 4449 | -Original Message- From: Pommerenke, David [SMTP:davi...@umr.edu] Sent: Thursday, May 08, 2003 5:46 PM To: John Woodgate; emc-p...@majordomo.ieee.org Subject: RE: ESD gun verification John, The IEC TC77b WG-9 made clarification for what was intended to be understood as verification and what was intended to be a calibration. Different words are used now, but the new version of he standard 77b/378/CDV tries to eliminate the misunderstanding by some metrologists. They think that the present standard requires a traceble calibration as a daily or weekly test, not only a yearly calibration. David Pommerenke -Original Message- From: John Woodgate [mailto:j...@jmwa.demon.co.uk] Sent: Thursday, May 08, 2003 1:25 PM To: emc-p...@majordomo.ieee.org Subject: Re: ESD gun verification I read in !emc-pstc that Pommerenke, David davi...@umr.edu wrote (in a5d66e6b6f478b48a3cef22aa4b9fca378e...@umr-mail1.umr.edu) about 'ESD gun verification' on Wed, 7 May 2003: Brain, Spelling! I like to repeat: For verification you do not need calibrated equipment or full bandwidth. The verification is just a method to increase trust in the calibration. If you use some homemade current target and a 500 MHz scope, you will get a pretty good picture of the waveform and detect most changes in an ESD generator. A comb-generator run on an OATS is not a NSA calibration, still it establishes trust in the antennas, cables and the spectrum analyzer. Quite right and sensible, but tell that to a UK metrologist! If it's not 200% accurate, it's not believable.(;-) -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk PLEASE do NOT copy news posts to me by E-MAIL! --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc This message is from the IEEE EMC Society Product Safety
RE: ESD gun verification
John, The IEC TC77b WG-9 made clarification for what was intended to be understood as verification and what was intended to be a calibration. Different words are used now, but the new version of he standard 77b/378/CDV tries to eliminate the misunderstanding by some metrologists. They think that the present standard requires a traceble calibration as a daily or weekly test, not only a yearly calibration. David Pommerenke From: John Woodgate [mailto:j...@jmwa.demon.co.uk] Sent: Thursday, May 08, 2003 1:25 PM To: emc-p...@majordomo.ieee.org Subject: Re: ESD gun verification I read in !emc-pstc that Pommerenke, David davi...@umr.edu wrote (in a5d66e6b6f478b48a3cef22aa4b9fca378e...@umr-mail1.umr.edu) about 'ESD gun verification' on Wed, 7 May 2003: Brain, Spelling! I like to repeat: For verification you do not need calibrated equipment or full bandwidth. The verification is just a method to increase trust in the calibration. If you use some homemade current target and a 500 MHz scope, you will get a pretty good picture of the waveform and detect most changes in an ESD generator. A comb-generator run on an OATS is not a NSA calibration, still it establishes trust in the antennas, cables and the spectrum analyzer. Quite right and sensible, but tell that to a UK metrologist! If it's not 200% accurate, it's not believable.(;-) -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk PLEASE do NOT copy news posts to me by E-MAIL! This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
ESD test standard - present CDV - justification for changes
Dear Jim, Thanks for taking the time to read the standard. Let me expand on the justification of the changes. Table of Content 1) New current target 2) On the correlation problems with ESD testing 3) Specific answers to your points (marked by ### in your email) David Pommerenke University Missouri Rolla 1) New current target = If you accept that a larger calibration bandwidth is needed (see my point (2)) then there is a need for a new target. The present target is only useful up to 1 GHz. Above 1 GHz targets that are build the same way differ a lot. The present target also has a high input impedance in the RF range (it reaches kOhm), so that the current is disturbed relative to a large ground plane. Now a target also needs to be calibrated, as one needs to determine if it fulfills its specification. This requires a either a network analyzer or a spectrum analyzer with tracking or a signal generator and a power meter. or a TDR in TDT arrangement. The good news is that this is only relevant for the manufacturer of the target, NOT FOR THE USER of the target. Now the construction of the new target is quite simple. I have made about 10 in the last years. There are also other constructions possible that are more simple. Note the target information is information, i.e., everyone can make their own target, as long as it measures correctly the construction does not matter. 2) On the correlation problems with ESD testing. Every ESD test is a combination of many physical tests. Disruption or disturbance can be caused by: a) dielectric breakdown b) Current (ohmic loss - thermal) c) Induction - voltage - oxid breakdown d) Induction - current - thermal e) Induction - disturbance f) Ohmic voltage drop - disturbance g) Inductive voltage drop - disturbance And there are many more. For each of them the question: - Is an ESD test reproducible? Will have a different answer. For example, the dielectric breakdown is strongly related to the voltage, and the voltage of ESD generators is well controlled. Now modern ICs can react to pulses of about 50ps width (just look at your PC). Now, induction is a differentiation process, e.g., it is a high-pass filter. The high frequency components of the current and the transient fields will dominate the circuit response (in this case: mostly disturbance, not destruction). If you compare the high frequency components of different ESD generator currents and fields, you will see differences larger than 20dB. As a consequence, failure levels for fast ICs (disturbance) will vary as much as 1:5 if ONLY the ESD generator is changed. This has been observed in many Industry applications and tests and is the main driving force for improving the standard. We are in the process of publishing results of such correlation under well controlled conditions and the analysis of the reasons (correlation: ESD generator parameters vs. disturbance failure levels). The paper is in the review-process of the IEEE Transactions on EMC. I will not post it here while it is in review, but I can email a pre-print version to interested individuals. From: Jim Ericson [mailto:jde...@nas.com] Sent: Tuesday, May 06, 2003 12:02 AM To: Pommerenke, David; emcpost Subject: Re: current-sensing transducer photos David: Thank you for the Committee Draft Version of the new ESD Standard. The committee is to be commended for producing such a thoroughly researched document that aims at improving test reproducibility of such a complex event as electrostatic discharge. While I am personally fascinated with the scientific aspects of ESD, I must say that the CDV rather took my breath away ... from the standpoint of ESD Current Target/Conical Adapter Line mechanical complexity ... to the cost implications for the EMC Laboratories and their clients. 4 GHz Current Targets, Network Analyzers, Oscilloscopes, and Electrostatic Voltmeters are far from trivial expenditures for any Laboratory. # Most test labs neither build ESD-current targets, not do they calibrate ESD generators themselves. For ESD-target and ESD-generator manufacturers, it is quire reasonable to expect that they can characterize the device they are building or calibrating. # I guess what I am missing is the underlying justification of need to change from the current 1 GHz approach. ## Please see my text above. There are more references that should be part of the CDV, they may also be in a justification document.# I don't mean to beat this subject into a dead horse. I am not qualified to do that (even if I wanted to) either from experience or education. I would only make the following comments from my perceptions based on 7 years with an EMC Lab, and 18 years building, testing, and evaluating Silicon for a couple of semiconductor manufacturers: 1. In the several years of performing (or directly
RE: ESD gun verification
Brain, I like to repeat: For verification you do not need calibrated equipment or full bandwidth. The verification is just a method to increase trust in the calibration. If you use some homemade current target and a 500 MHz scope, you will get a pretty good picture of the waveform and detect most changes in an ESD generator. A comb-generator run on an OATS is not a NSA calibration, still it establishes trust in the antennas, cables and the spectrum analyzer. David Pommerenke University Missouri Rolla From: brian_ku...@leco.com [mailto:brian_ku...@leco.com] Sent: Monday, May 05, 2003 1:04 PM To: emc-p...@ieee.org Subject: Re:ESD gun verification John, First I would like to say how impressed I am with Jim for building his own target. Reading through his detailed description of all he went through made me think the $2000 is well worth it. I wish I had the skill and resources to do stuff like that. Years ago we used to just air discharge our ESD gun to make sure it was working ok. We never performed a verification test. This we thought was covered by the annual calibration and assumed that the ESD gun was designed solid enough to not have to worry about it. It wasn't until some of these Laboratory Accreditation organizations got popular that daily verification of your ESD gun required the verification of the current waveform. This makes a fairly inexpensive test very expensive for most labs. In addition to the $5000-$8000 for the ESD gun, now you have to have the equipment to do verification. For us this was a $2000 target, a faraday cage, and a $20,000 1Ghz bandwidth digital storage scope. If you are testing everyday your very expensive scope is for the most part dedicated for this purpose. You can use cheaper scopes, but it has to have a high bandwidth and storage capabilities. A huge investment no doubt if you want to do it right. BTW, don't you also have to verify your scope is working correctly? Hmmm. The other issue is with the time involved with performing the verification test. To look at all the details of the current waveform for just a few voltages both positive and negative polarity plus the time to document and keep records of it takes time many customers don't want to pay for. Somehow you have to work in the cost because time is money and someone has to pay for it. To test every voltage level and polarity can take more time than the ESD test itself. So a happy reasonable medium has to be found. In a perfect world someone would invent a little box I can discharge my ESD gun into and a little green light would come on to tell me it is operating OK. If someone could invent such a box and keep it inexpensive, I would buy one. Of course it would probably cost a fortune to get the box calibrated and how do I verify the box is working correctly? Hmmm. Brian Reply Separator Subject:ESD gun verification Author: jde...@nas.com List-Post: emc-pstc@listserv.ieee.org List-Post: emc-pstc@listserv.ieee.org List-Post: emc-pstc@listserv.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: 5/05/03 12:02 PM John: I faced the same problem about six years ago. I needed to do verification in between the expensive annual calibrations. I first explored the option of buying a Pelligrini Target. As I recall, the quotes I received were around $2000. That seemed outrageous, so I decided to build one myself. I'll bet it took me at least 3 days to make sense of those goofy mechanical drawings in 61000-4-2. If only they had included a photograph or good cross-section in the Standard! Anyway, I finally figured it out, translated the drawings into something understandable by a U.S. machine shop, and got all the brass parts fabricated locally. It took several in-process consulting sessions with the machinist, but I finally got all the brass parts done for around $300. Then, I purchased a $25 silver electroplating kit. It was like Science Fair time in my workshop! Some hours of painstaking soldering later, the target was completed. I mounted it over a specially-drilled hole in the brass wall panel of our anechoic chamber (you need a Faraday Cage of some sort, and this seemed the easiest). I did a quick check using our Tektronix 1 GHz analog oscilloscope ... and the risetimes and overall waveforms measured within spec! Then, I sent the target to Haefely-Trench for a calibration (against their standard Pelligrini target). The results were very, very close. Having performed many verifications at this point, my advice (if you want fairly accurate and repeatable results): 1.Make (or buy) something resembling the 61000-4-2 target. 2.Use a Faraday Cage. 3.Be aware how important the POSITION of the ESD Gun Grounding Strap is to these measurements ... especially to risetime measurements. I always take a photograph of the setup, including the shape of the Grounding Strap and where it is attached. If you don't do this, you'll
RE: ESD gun verification
Dear John, It depends on what you want. But at first we need to discuss one issue of definition of verificaiton, calibration or all kinds of similar words. I define a calibration as a traceble measurement and a verification as a measurement that helps to establish confidence that some instrument is still OK. A verification by this definition is not traceble. In EMC, using a comb-generator daily to check you emissions equipment (antenna + amp + cable + SA) is a verification. 1) If you are going to do a formal calibration, you have to follow the standard and have to have a bandwidth of at least 1 GHz. 2) If you are just doing a verification, you can build your own current target, even if it only works so and so. Then you take some oscilloscope, e.g., 500 MHz bandwidth and do a reference measurement after the ESD generator has been calibrated (see above for definition). From that day on, you dischare the generator into your self-made structure and compare to the reference. Now you need to derive some useful criteria to handle diviations. But in general, your aim is just to establish more confidence in the ESD generator's calibration status. So your measurement do not need to capture all parameters in good fidelity. Of course, you have to do your traceble calibration, e.g., every year or so. The present ESD standard is not very clear in the use of verification and calibration. But the definitions above are the ones that TC77b-WG-9 intended. The new version of the standard, that is in a CDV stage, clarifies this better. David Pommerenke University Missouri Rolla From: John Harrington [mailto:jharring...@f2labs.com] Sent: Thursday, May 01, 2003 1:46 PM To: 'emc-p...@majordomo.ieee.org' Subject: ESD gun verification Hello All Does any one have a quick and dirty (and hopefully cheap) way to verify the performance of an ESD gun. Please, no one suggest building the current sensing system described in the back of IEC 61000-4-2. I don't understand the drawings let alone have the workshop or materials to consider it. Although, I may pay someone to build it for me... I am desperate enough to consider buying something off the shelf (if I could find said shelf). All help appreciated John Harrington EMC Technical Manager F-Squared Laboratories This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: equipment question
Dear Chet, Modeling the frequency response is not a totally trivial task. In general, there are two different design strategies: 1) Gauss-roll off This scopes have an approximately Gauss-roll off with frequency. As a Consequence the ratio of F_sample to F_bandwidth has to be at least 4:1 to avoid alaising. This scope design results in a good (no overshoot) step response for in-band signals (rise-time of the original signal is such that most frequency components are within the 2 GHz bandwidth) and a good step response for out of band signals (very fast risetime, much faster than the scope's risetime). For sine-wave measurements of in-band sine wave frequencies, of course, this scopes will be influenced by the roll-off 2) Flat frequency response. This scopes have a flat frequency response up to about F_sample/2.5. Then the frequency response rolls-off very sharply. This scope yield good data for in-band sine wave and in-band step waves. But for out of band step waves (very fast risetime), the step response of the scope may show pre-shoot, overshoot and ringing. There is some literature on the frequency response of scopes, you most likely find it in the transactions on instrumentation and measurements. Now the issues are much more tricky than from a pure analoge, linear system analysis. Many scopes have an adaptive interpolation method. The method tries to find out if the signal was in-band or out of band. Now depending on that it will use a different interpolation method. Next aspect to take into account is that the input impedance match is often not very good. So for detailed work, you have to take reflections and multple reflections into account. If you do not use the 50 Ohm input, please also take into accuont that the 1Mohm/10 pF setting has a much more complex input equivalent circuit that these values. For higher frequencies the impedance would be very low, so the manufactureres add some series resistance in the 10 pF. As a consequence, each passive probe will react differently to the scope input, i.e., you do not only have to compensate the low frequency, but also adjust the other potentiometers and capacitors inside the probe (they are often hidden) to obtain a flat frequency response at higher frequencies, if the probe was not made for that specific oscilloscope. Secondly, the frequency response is often effected by the mV/div setting. So ist he input impedance of some scopes. I do not know what you are intending to do with the frequency response, but if you intend to do some deconvolution (correction of the frequency response, or correction of measured data) I need to warn you. You may introduce more problems by over-compensating, so that the overall measurement uncertainty is increased. The web-sites of LeCroy, Agilent and Tektronix have all kinds of very good information on the frequency response. Regards, David Pommerenke This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: ESD Contact discharge fitted connector
Kris, In my reading of the standard, and the next modificaiton will include that clearly, you need to test discharges to the shell of the USB connector, as there will not be a connector in there all the time. There is another strong arguemnt: The user might plug a charged (e.g. hand-held) device into the USB port. Of course, the main criteria is survival, as you cannot test connectivity if there is no USB device. But if you have multiple USB connectors, another USB device might loose connection when discharging to a different USB connector. David Pommerenke From: Carpentier Kristiaan [mailto:carpenti...@thmulti.com] Sent: Wednesday, January 22, 2003 10:48 AM To: emc-p...@majordomo.ieee.org Subject: ESD Contact discharge fitted connector Hello group, A Class II product has 3 interfaces. 2 interfaces have plastic connectors, with no metal shell. 3rd interface is USB plastic connector but with metal shell. The housing of the product is plastic (non conductive) The USB connector is fitted with a USB plug molded in plastic. Test set-up for immunity testing (ESD) is done with all interface plugs connected to verify performance of all interfaces. Consequently, no conductive parts are accessible and contact discharge must not be applied. But the product can also used without USB connection; the USB connector shell becomes then accessible. Question: Is ESD Contact test required on USB connector without plug taken into account that USB performance cannot be monitored at that time (and the other interfaces must be verified in another way)? More generic: can we exclude ESD contact testing by fitting all connectors with plugs on a product ? FYI: IEC61000-4-5+A1+A2 states that Contact ESD is not required (par 8.3.1 c) for those points and surfaces of equipment which are no longer accessibel after FIXED installation or after following the instructions for use. Regards, Kris This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: Changes to IEEE emc-pstc web-based services
Dear Group, My experience is that with WEB-based systems there will be significantly less participation. Posting of large documents, as people will not carefully think about file size, compression down-sampling etc will make it worse for people on dial-up connections. Discussions will be based on the knowledge of those documents. Without strong reason the present system should not be changed. I am not aware of those strong reasons. David Pommerenke This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: ESD Testing Method
Dear Alex McNeil, The intend of the standard is that each discharge is an individual event. This means: Electromagnetic consequence === All charges need to be drained before the next discharge is applied. You may use an Ionizer, a conductive brush, a ground wire etc. to remove the charge from the EUT. Be aware: An Ionizer may change the test results for air discharges a lot. Software consequence It is not the aim to apply an discharge while the EUT is still in some error correcting algorithm. So one can apply discharges at a fast rate, e.g., 20 pulses a sec to up the number of discharges (with 10 discharges the ESD test result uncertainty may be dominated by the time dependence of the susceptability function). Still, one needs to make sure that the EUT is back to its original software status before the next ESD is applied. David Pommerenke -Original Message- From: Alex McNeil [mailto:alex.mcn...@ingenicofortronic.com] Sent: Tuesday, December 03, 2002 10:16 AM To: 'emc-p...@majordomo.ieee.org' Subject: ESD Testing Method Hi Guys, 1. For double insulated products (non-earthed) is it correct to state that the ESD test point, for Contact Discharge (CD) tests, should be discharged prior to applying the next discharge (I am sure I read this somewhere, but)? 2. As a follow on from the first question, I have a product that will pass +8KV Contact Discharge (CD) in +2KV steps. It will also pass -8KV CD in -2KV steps. However, if I test +XKV (50 zaps) followed by -XKV (1 zap) it will fail. What is the correct procedure as the standard does not say if +CD should follow -CD or vice versa or step up with the same polarity? In my opinion it would be unlikely in a particular customer environment that the +XKV would be quickly followed by a -XKV (or vice versa). I look forward, as per usual, to your kind and expert responses. Kind Regards Alex McNeil Principal Engineer Tel: +44 (0)131 479 8375 Fax:+44 (0)131 479 8321 email: alex.mcn...@ingenicofortronic.com --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: Circuit pack ESD drain
Dave, If you can give me the dimensions we can numerically calculate or analytically estimate the waveform. David Pommerenke -Original Message- From: David Heald [mailto:dhe...@tellium.com] Sent: Thursday, October 31, 2002 4:58 PM To: 'emc-p...@majordomo.ieee.org' Subject: Circuit pack ESD drain All, Does anyone know of a sample waveform or general characteristics for worst case VI on an ESD drain pin when a circuit pack is inserted into an equipment shelf? This is an odd question I know, but my management asked for the info and I really have no idea (and it shouldn't happen anyway ;o) I guess even a typical maximum charge that can be expected to be on a circuit pack would be sufficient information. Thanks in advance! Dave Heald --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
AW: An ESD question
Dear Group, In dry conditions, not only the charging processes are enhancec, but the severity (less risetime, higher peak current) is enhanced in general. For both reasons, it is not uncommen to see ESD problems move around the world with the local seasons. Still, I would always try to debug the problem in contact mode. The effect on humidity on the electromagnetic properties is in general very small. Aim of the debugging should be to identify the traces, nets of PINs that are effected. Locally injecting pulses via direct, capacitive, inductive or differential injection has prooved to be an effective tool for achieving this. David -Ursprüngliche Nachricht- Von:Gibling, Vic [mailto:vic.gibl...@marconi.com] Gesendet: Mi 12.06.2002 02:26 An: emc-p...@majordomo.ieee.org Cc: Betreff:An ESD question Dear Group I tried to find David Pommerenke article's in the Journal of ESD on the Web but alas no downloadable version was found, so may I ask the group a question? We have an ESD field failure which is occurring in dry hot countries ( no surprise )which can be recreated with an ESD of -800V. In an attempt to get a high incidence of discharges we used a dehumidifier to create a dry environment. The result was a reduction in discharges. Thinking the problem through -now- as a dry atmosphere will encourage the production of high level ESD and a humid environment inhibits the charge to a lesser level, presumably because it 'leaks' away. Then is it wrong for us to attempt to 'dry' the local atmosphere in the hope of gaining consistent ESD from an ESD gun, that is to say the more humid the environment the more efficiently the discharge will transfer to the victim? Incidentally, to add to the thread regarding intermediate level testing for ESD and EFT. This exercise has revealed different failure mechanisms at different ESD levels. Your views would be appreciated. Vic Gibling Compliance Engineer Marconi Applied Technologies --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: IEC 61000-4-2 ESD 61000-4-5 Surge lower levels
Dear Group, The physics of air discharge (= the reason for the variatins, the effect of humidity, speed of approach) is quite well explained in D. Pommerenke, 'ESD: Transient Fields, Arc Simulation and Rise Time Limit' , Journal of Electrostatics 1995 36 (1995), pp. 31 - 54 David Pommerenke --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: IEC 61000-4-2 ESD 61000-4-5 Surge lower levels
Dear Scott, (1) I have looked at quite a bit of literature that plots Failure propatibility vs. Stress level in contact mode like testing and have seen very few none-monotonic EUTs that show the none-monotonic behavior over a larger voltage range. (2) In my five year test practise at HP, I have only seen one EUT that failed at lower levels and passed at higher levels in contact mode. If you have data that showsAs others have said, I have seen numerous failures at less than the maximum required test voltage while the same system passes at the max required voltage. please share that data with me if it is in contact mode and if the number of discharges at each level is large enough to obtain an acceptable confidence level. Regards David Pommerenke [Pommerenke, David] -Original Message- From: Scott Douglas [mailto:dougl...@naradnetworks.com] Sent: Monday, June 10, 2002 4:46 PM To: emc-p...@majordomo.ieee.org Subject: RE: IEC 61000-4-2 ESD 61000-4-5 Surge lower levels David, I disagree with you here. As others have said, I have seen numerous failures at less than the maximum required test voltage while the same system passes at the max required voltage. It seems to me the intent was / is / should be to verify product performance up to a maximum level, not just at that level. The logic here would be that the standards writing group would make the test cover reasonable ground up to some limit because it is quite common that anything up to that limit could happen. The reason for the limit is because it is uncommon for things larger / higher than the limit to happen. Contact discharge is the only way to make reliable and repeatable tests for ESD. No approach speed issues, etc. So testing at low levels and working up to a maximum limit is a reasonable test method. On the other hand, I find air discharge to be a difficult and not very repeatable test to do which causes me to question its usefulness. Yes, I agree that people interacting with products will more often see air discharge rather than contact discharge. But I also find it impossible to reliably repeat air discharge test results. The old approach speed, distance and coordinates of contact point issue. Until someone can make an automated air discharge tester that keeps human interactions out of the process, I can't see it being corrected. That said, testing at lower levels is just as necessary here. Regards, Scott Douglas Senior Compliance Engineer Narad Networks 515 Groton Road Westford, MA 01886 office: 978 589-1869 cell: 978-239-0693 dougl...@naradnetworks.com www.naradnetworks.com http://www.naradnetworks.com/ At 08:36 AM 6/10/02 -0500, Pommerenke, David wrote: Dear Group, For most EUTs there is no need to do lower level testing in contact mode ESD. The time is better spend (meaning a better test results uncertainty is achieved) if the number of discharges is increased at the highest test level (hundreds is a good number). Although it is possible that a system fails at e.g., 2 kV contact mode (e.g., incomplete reset) and passes at 4 kV contact mode (full self-recovering quick reset) the likelyhood of that happening is not that large to require it in a standard. For air discharge lower level testing is needed, as the risetime is often much lower at lower voltages. Of course, if no discharge occurs, no further testing at even lower levels makes sense. I do know that what I am saying violates the present IEC 61000-4-2 standard. ut it reflects the coming version of IEC 61000-4-2. The standard does not intend to protect agains every possible ESD failure. I would like to receive your input, as I am one of the US-representatives in IEC TC77b WG-9 (ESD). David Pommerenke
RE: IEC 61000-4-2 ESD 61000-4-5 Surge lower levels
Dear Group, For most EUTs there is no need to do lower level testing in contact mode ESD. The time is better spend (meaning a better test results uncertainty is achieved) if the number of discharges is increased at the highest test level (hundreds is a good number). Although it is possible that a system fails at e.g., 2 kV contact mode (e.g., incomplete reset) and passes at 4 kV contact mode (full self-recovering quick reset) the likelyhood of that happening is not that large to require it in a standard. For air discharge lower level testing is needed, as the risetime is often much lower at lower voltages. Of course, if no discharge occurs, no further testing at even lower levels makes sense. I do know that what I am saying violates the present IEC 61000-4-2 standard. ut it reflects the coming version of IEC 61000-4-2. The standard does not intend to protect agains every possible ESD failure. I would like to receive your input, as I am one of the US-representatives in IEC TC77b WG-9 (ESD). David Pommerenke -Original Message- From: Neil Helsby [mailto:nei...@solid-state-logic.com] Sent: Monday, June 10, 2002 4:56 AM To: emc-p...@majordomo.ieee.org Cc: kro...@yahoo.com Subject: Re: IEC 61000-4-2 ESD 61000-4-5 Surge lower levels I think there are two points here. 1) If you believe that in the environment in which it will be used, your product may be subject to levels in excess of that defined in the standard, you must test to that higher level. 2) Yes, failures can occur at mid range levels. We have just recently experienced this problem with ESD. Below about 3.5 kV and above about 4.5 kV the product worked fine. But at 4 kV we experienced a failure mode. If we had only tested at 8 kV we would have missed the problem. I also had a problem some years ago with mains voltage dips to 0V. Having a test set that enabled the period to be varied in ms increments, I discovered a problem affecting a voltage regulator. When the mains dip was between about 16 ms and 35 ms, the regulator went into a bistable mode switching on then off at each pulse. Outside these periods, it worked satisfactorily, eventually losing output when the period was extended. The problem with investigating these types of failure is determining the size of step between measurements. Too short a step and you will be testing forever, too long and you could miss a narrow band of problem. Regards, Neil Helsby ** This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the system manager. This footnote also confirms that this email message has been swept by MIMEsweeper for the presence of computer viruses. www.mimesweeper.com ** --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: Suitable CDN for IEC61000-4-6 ethernet 10/100
What you should take into account is the failure criteria for 61000-4-6 as seen by the EU: No degradation beyond manufactueres specification. Depending on the EUT just a few additional bit-errors at any of the tested frequencies may be a fail. It may not be sufficient to just look at loss of link. In many cases, a low level LAN-analyzer is needed to do this test. Otherwise, effects of lessere severeness than loosing link will not be detected, although they may be a fail of the test. David Pommerenke -Original Message- From: Chris Maxwell [mailto:chris.maxw...@nettest.com] Sent: Friday, April 19, 2002 7:53 AM To: emc-p...@majordomo.ieee.org Subject: RE: Suitable CDN for IEC61000-4-6 ethernet 10/100 From David Sterner's message: Most people use the EM clamp. We test to EN50130-4 alarm system limits: 10V, pulsed and AM modulated. The test is trivial because of the inherent immunity of Ethernet; be sure you understand the EUT and AE port partitioning algorithms. What! The test is trivial because of the inherent immunity of Ethernet. The last product that I took through the lab couldn't even take 3V...heck, the Ethernet cable couldn't even take 3V being put on some of the other cables in the chassis. Now, before everybody sends me design tips for Ethernet immunity...save your breath... the chassis was a purchased computer. It was EMC tested (with only a dummy ethernet cable and no traffic, mind you). And I have no design control of the ethernet circuit. We ended up using shielded Ethernet cables and invoking the 3meter rule. The point that I'm trying to make is...I'm glad that this test is trivial for your products. Obviously, you have a good design there(Where were you when we were looking for a compliant mainframe to use with our system?) But this type of immunity performance cannot be attributed to all Ethernet ports in general or to the Ethernet protocol in general. Best regards, Chris Maxwell | Design Engineer - Optical Division email chris.maxw...@nettest.com | dir +1 315 266 5128 | fax +1 315 797 8024 NetTest | 6 Rhoads Drive, Utica, NY 13502 | USA web www.nettest.com | tel +1 315 797 4449 | --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: ESD Generator confidence test - Pelligrini Target
Just one comment on the Pelligrini Target: We compared different Pelligrini Targets that were all made to the specifications. - Up to 1 GHz they perform reasonably close - Above 1 GHz large differences show up, although they are all made to the drawings. - All of them show resonances in their S21 above 1 GHz. - The input impedance goes up into the kOHm range, i.e., the current that is injected is very different from the current that would be injected into a large ground plane. Consequence === If you use a scope with 1 GHz bandwidth, the Pelligrini Target is good. That is what it was designed for. If you use a scope with 1GHz bandwidth, you should use a better target AND characterize the frequency response of the target - attenuator - cable chain. The differences between a good target and the Pelligrini target will get worsen if: - you use larger bandwidth - you analyze the current derivative or the ringing on the rising edge. Regards David Pommerenke --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: ESD Generator confidence test
Dear Group, There is a big misunderstanding about verification, calibration, daily check etc. I am member of IEC TC77B WG-9 (ESD). We discussed what we want the user to do and the present opinion is as follows (A new draft of the ESD standard will reflect this position): (1) Formal calibration === Every year (or any other interval set by the quality system) a formal calibration of the ESD simulator is done. This requires using calibrated equipment and tracebility. (2) Tests done to gain confidence that the simulator is still within specs === At intervals totally determined by the user a quick check is done. This does NOT require tracebility. For example, if the user uses a 500 MHz (too slow for an official calibration) scope to check the waveform at one level and one polarity. Now the user compares the waveform from the 500 MHz scope to the a waveform obtained after the last formal calibration. Using engineering judgement, the user can not determine if the ESD generator is probably still OK. What is important to note: Only for the formal calibration calibrated equipment is needed. Typically, this is done once a year. Every other method to gain confidence in the ESD simulator status does NOT have to be traceble. For example, for a quick check (weekly) at some HP sites a system (Has been published in Compliance Engineering) is used that measures the peak current and its pulse-to-pulse variations (using an extremly fast peak detector). Now if the peak current is OK, the assumption is made that the generator is still OK. This assumption is based on the experience that most failures in an ESD simulator will show up as a change of the peak current. The method has been accpeted by A2LA, DATech and other accreditation agencies. Still, this is not an official statement by IEC. Regards David Pommerenke -Original Message- From: Michael Taylor [mailto:mtay...@hach.com] Sent: Monday, February 25, 2002 12:32 PM To: 'Kevin Harris'; 'vic.gibl...@raytheon.co.uk'; emc-p...@majordomo.ieee.org Subject: RE: ESD Generator confidence test We looked at the unit and almost purchased one. However, we discovered the annual cost to ship it back to Belgium + the calibration costs amounted to almost 78% of the purchase price. It just was not economical. If someone in the USA could calibrate it at lower cost it's a great product. Michael Taylor Still shoveling snow in Colorado -Original Message- From: Kevin Harris [ mailto:harr...@dscltd.com] Sent: Monday, February 25, 2002 7:59 AM To: 'vic.gibl...@raytheon.co.uk'; emc-p...@majordomo.ieee.org Subject: RE: ESD Generator confidence test Vic, A couple of years back at the Seattle IEEE EMC show a go/ no go confidence tester for static testing was discussed and demonstrated. I'm not sure if that still is commercially available but if you email Ivan Hendrikx at i...@hevrox.be he will be able to tell you more I'm sure. Best Regards, Kevin Harris Manager, Approval Services Digital Security Controls 3301 Langstaff Road Concord, Ontario CANADA L4K 4L2 Tel: +1 905 760 3000 Ext. 2378 Fax +1 905 760 3020 Email: harr...@dscltd.com -Original Message- From: vic.gibl...@raytheon.co.uk [ mailto:vic.gibl...@raytheon.co.uk] Sent: Monday, February 25, 2002 9:00 AM To: emc-p...@majordomo.ieee.org Subject: ESD Generator confidence test The ESD standard IEC 61000-4-2 gives details for the manufacture of a current target, used for verifying the ESD waveform. I appreciate this could be used as a confidence check before administering the test, but does anyone have another approach that they would be willing to share. Many thanks Vic Gibling EMC Engineer Raytheon Systems Limited --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list
RE: Using PCB traces as transient voltage suppressor
Gabi, The topic of an air-discharge spark gap is a little bit more complicated. 1) The breakdown voltage in air for a homogeneous field is given by the Paschen-equations, providing that the breakdown is a gas discharge process, not an explosive surface process (happens at high pressure, distances less than about 5um and if the gap is highly overvoltaged) Even for a homogenous field, the breakdown fieldstrength is a strong function of voltage. 2) A spark gap will need some time to turn on. There are two processes: Statistical time lag: this is the time it takes before the first electron appears that can start the avalange process. Time lags may be ps to seconds, depending on the field strength and many other factors. 3) Formative time: The time the spark needs from its start until its impedance is low. The time may be ns to us. 4) Clamping voltage. Typically spark gaps clamp at about 25 V for currents of less than 100 A in time frames of 10ns to a few hundred ns. I do not know the physical reason for the 25 V. If anyone knows, please let me know. 5) In my experience a PCB using the footprint of an 0805 part (not loaded) will break down at about 2000-3000V. 6) It is not easy to get breakdown voltages consistantly below 500 V with spark gap structures in air. The needed distances are so small that surface properties, contamination etc. start to dominate. Regards David Pommerenke Associate Professor Electromagnetic Compatibility Laboratory ECE Department University of Missouri-Rolla 1870 Miner Circle Rolla, MO 65409-0040 pommere...@ece.umr.edu Phone: (573) 341-4531 Home: (573) 341 5835 FAX: (573) 341-4532 -Original Message- From: Gabi Hoffknecht [mailto:gab...@simex.ca] Sent: Wednesday, February 20, 2002 10:33 AM To: emc-p...@majordomo.ieee.org Subject: Using PCB traces as transient voltage suppressor Hi all, I have seen PCB designs with two triangular shaped copper pads pointed towards each other at very close proximity, meant as an air gap discharge path for transients. Does anyone have information about such designs, whether they work and how well ? At a breakdown voltage for air of 1 Megavolt per meter, they should theoretically work: 10mil distance would have a breakdown voltage of only 254V. Such a PCB design basically comes for free, so I was thinking of adding it on top of my already existing series impedance - TVS network. Thanks in advance for your comments. Best regards, Gabi Hoffknecht --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: ESD Simulator Evaluation
Richard, There are two reasons for this: Physical reason === 1) When you are approaching with an ESD simulator there is a distance at which a spark MAY occur. This distance can be calculated ONLY for a homogenious field quite well, using Paschen's equation. In a homogeneous field those values are: 30 kV - 1 cm 10 kV - 2.8 mm 5 kV - 1.1 mm 3 kV - 0.55 mm for sea-level air pressur. Humidity has hardly any influence on this value. For in-homogenous field, the values are longer, but not easy to calculate. As you said 1 inch at 30 kV the field must have been inhomogenous. Never mind: Just remember: If you approach there is a certain distance at which a breakdown MAY occur, if you wait long enough. Now as you are approaching and passing this distance there MUST not be a breakdown. The breakdown will only happen if there are initial charge carriers that initiated the breakdown. If there is a lack of such charge carriers, the distance between the tip and ground will be further reduced, until the breakdown is initiated. So in your case that may be the reason: Using fast approach the voltage was OK, but the shorter sparks are caused by a delayed onset. The delay of the onset is a statistical process (called statistical time lag) and the reason for the bad reproducibility of air discharge testing. Instrumentation reason == 2) The voltage was not OK. I doubt that, as the voltage will not be dependent on the approach speed. The voltage may depend on corona, but if the the tip is not pointed, there will probably not be corona. David Pommerenke Associate Professor Electromagnetic Compatibility Laboratory ECE Department University of Missouri-Rolla 1870 Miner Circle Rolla, MO 65409-0040 pommere...@ece.umr.edu Phone: (573) 341-4531 Home: (573) 341 5835 FAX: (573) 341-4532 -Original Message- From: richwo...@tycoint.com [mailto:richwo...@tycoint.com] Sent: Tuesday, December 04, 2001 9:32 AM To: emc-p...@majordomo.ieee.org Subject: ESD Simulator Evaluation An engineer was evaluating ESD simulators and observed an interesting phenomenon. The air discharge tip was placed at a fixed distance of about 1 inch from a ground reference plane with the simulator set for 30 kV and a healthy spark was launched by all of the simulators. HOWEVER, when he started from some distance and rapidly approached the grp, one of the simulators appeared to have lost 2/3 of the charge. The other 3 did not. He base the conclusion on the fact that the spark launched from about 1 inch for 3 simulators, but launched from about 1/3 inch from one unit when using the rapid approach air discharge method. Any suggestions on what is happening here? Evaluation of simulators is specified using a target with the tip contacting the target. We did not see a parameter in the standard that allows one to evaluate the ability of a simulator tip to hold a charge. Did we miss something? Richard Woods Sensormatic Electronics Tyco International --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
RE: Pre-amps
Ken, The added uncertainty is exactly as large as if you have a piece of cable (assume too short to have relevant losses) inbetween. David Pommerenke -Original Message- From: Ken Javor [mailto:ken.ja...@emccompliance.com] Sent: Friday, November 16, 2001 12:05 PM To: Pommerenke, David; 'ravinder ajmani'; marti...@appliedbiosystems.com Cc: emc-p...@majordomo.ieee.org Subject: Re: Pre-amps Note I am replying to all. What is the measurement inaccuracy associated with a mismatch if the transmission line is vanishingly short (relative to a wavelength)? -- From: Pommerenke, David davi...@ece.umr.edu To: 'Ken Javor' ken.ja...@emccompliance.com, 'Ravinder Ajmani' ajm...@us.ibm.com, marti...@appliedbiosystems.com Cc: emc-p...@majordomo.ieee.org Subject: RE: Pre-amps Date: Fri, Nov 16, 2001, 8:10 AM Dear Ken, I am thinking you are missing something (hope that I am correct). If you simply shorten the cable to zero, the problem of the missmatch, and the effect of an error that is not corrected for by the antenna factor still remains. David Pommerenke -Original Message- From: Ken Javor [mailto:ken.ja...@emccompliance.com] Sent: Thursday, November 15, 2001 5:51 PM To: Pommerenke, David; 'Ravinder Ajmani'; marti...@appliedbiosystems.com Cc: emc-p...@majordomo.ieee.org Subject: Re: Pre-amps If input VSWR for preamp and output VSWR for antenna are both bad, then it seems a simple solution is to connect preamp input to antenna output and let 50 Ohm output of preamp drive cable, solving two problems at once. Am I missing something? -- From: Pommerenke, David davi...@ece.umr.edu To: 'Ravinder Ajmani' ajm...@us.ibm.com, marti...@appliedbiosystems.com Cc: emc-p...@majordomo.ieee.org Subject: RE: Pre-amps Date: Thu, Nov 15, 2001, 7:49 AM On the amps: For emissions there are the following electrical criteria: - Noise figure expect about 4 dB for a broadband amp 30 MHz - 2 GHz. The noise figure is often larger at the lower frequencies if the amplifier goes up to many GHz. - Input SWR. This is important. Most broadband amps (especially if they go up to many GHz) have a bad input match at low frequencies. As the log-per antennas have a bad mismatch too, you will have multiple reflections on the cable between the antenna and the pre-amp. This reflections will influence your measurement and cannot be corrected for by the antenna factor. They may be as large as a few dB below 100 MHz. For that reason, you may be forced to add a 3 dB attenuatore at the antenna. This increases your noise figure by 3 dB. - Gain. Of course, you need only as much gain as is needed to overcome the cable loss (cable to the spectrum analyzer) and the noise figure of the spectrum analyzer. More gain will not help you. David Pommerenke -Original Message- From: Ravinder Ajmani [mailto:ajm...@us.ibm.com] Sent: Wednesday, November 14, 2001 1:27 PM To: marti...@appliedbiosystems.com Cc: emc-p...@majordomo.ieee.org Subject: Re: Pre-amps Joe, HP (Agilent) make good Pre-amps for different frequency ranges. If you are looking for an economical solution then you may try Com Power Corp. at (949) 587-9800. Regards, Ravinder PCB Development and Design Department IBM Corporation Email: ajm...@us.ibm.com *** Always do right. This will gratify some people and astonish the rest. Mark Twain MartinJP@appliedbiosyst ems.com To: emc-p...@majordomo.ieee.org Sent by: cc: owner-emc-pstc@majordom Subject: Pre-amps o.ieee.org 11/14/2001 10:14 AM Please respond to MartinJP I am having some difficulties locating manufacturers that provide preamps with a 20-22dB gain. What manufacturer/model do you recommend? Why? Your assistance is appreciated. Regards Joe Martin Applied Biosystems --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server
RE: Pre-amps
On the amps: For emissions there are the following electrical criteria: - Noise figure expect about 4 dB for a broadband amp 30 MHz - 2 GHz. The noise figure is often larger at the lower frequencies if the amplifier goes up to many GHz. - Input SWR. This is important. Most broadband amps (especially if they go up to many GHz) have a bad input match at low frequencies. As the log-per antennas have a bad mismatch too, you will have multiple reflections on the cable between the antenna and the pre-amp. This reflections will influence your measurement and cannot be corrected for by the antenna factor. They may be as large as a few dB below 100 MHz. For that reason, you may be forced to add a 3 dB attenuatore at the antenna. This increases your noise figure by 3 dB. - Gain. Of course, you need only as much gain as is needed to overcome the cable loss (cable to the spectrum analyzer) and the noise figure of the spectrum analyzer. More gain will not help you. David Pommerenke -Original Message- From: Ravinder Ajmani [mailto:ajm...@us.ibm.com] Sent: Wednesday, November 14, 2001 1:27 PM To: marti...@appliedbiosystems.com Cc: emc-p...@majordomo.ieee.org Subject: Re: Pre-amps Joe, HP (Agilent) make good Pre-amps for different frequency ranges. If you are looking for an economical solution then you may try Com Power Corp. at (949) 587-9800. Regards, Ravinder PCB Development and Design Department IBM Corporation Email: ajm...@us.ibm.com *** Always do right. This will gratify some people and astonish the rest. Mark Twain MartinJP@appliedbiosyst ems.com To: emc-p...@majordomo.ieee.org Sent by: cc: owner-emc-pstc@majordom Subject: Pre-amps o.ieee.org 11/14/2001 10:14 AM Please respond to MartinJP I am having some difficulties locating manufacturers that provide preamps with a 20-22dB gain. What manufacturer/model do you recommend? Why? Your assistance is appreciated. Regards Joe Martin Applied Biosystems --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
RE: EMC test table construction plans
John, You are arguing Should the test conditions not reflect the actual environment in use of the product, rather than employ these unusual materials? The problem is that we do not know the actual conditions. So we need to define the test conditions. If everyone use be using the SAME wooden table, it would be fine. But that is not the case and there are large variations between different wooden tables, surface materials etc. So if one uses a wooden table, its influence must be taken into the uncertainty calculation. This adds a few more dBs, much more above 1 GHz. In radiated immunity it is even worse, as there is no maximization done. David Pommerenke -Original Message- From: John Woodgate [mailto:j...@jmwa.demon.co.uk] Sent: Friday, November 02, 2001 1:34 AM To: emc-p...@majordomo.ieee.org Subject: Re: EMC test table construction plans I read in !emc-pstc that Pommerenke, David davi...@ece.umr.edu wrote (in 9da8d24b915bd1118911006094516eaf0ba31...@umr-mail02.cc.umr.edu) about 'EMC test table construction plans', on Thu, 1 Nov 2001: For emissions and immunity you should not use any wood in the table. It will significantly (+/-2 dB up to 1 GHz for emissions , more above, +/-10 dB for immunity up to 1 GHz) change the test result. My experience has shown that Styrofoam is basicly the best material. You mean that it gives the worst-case results? There are a couple of published papers on this issue. As surface material the following worked out fine: - Foamed PVC (rather stiff, low dielectric constant due to the foamed nature), maybe 4 mm thick. - PE sheet, maybe 2 mm thick. Should the test conditions not reflect the actual environment in use of the product, rather than employ these unusual materials? -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Eat mink and be dreary! --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
RE: EMC test table construction plans
Doug, For emissions and immunity you should not use any wood in the table. It will significantly (+/-2 dB up to 1 GHz for emissions , more above, +/-10 dB for immunity up to 1 GHz) change the test result. My experience has shown that Styrofoam is basicly the best material. There are a couple of published papers on this issue. As surface material the following worked out fine: - Foamed PVC (rather stiff, low dielectric constant due to the foamed nature), maybe 4 mm thick. - PE sheet, maybe 2 mm thick. David Pommerenke -Original Message- From: POWELL, DOUG [mailto:doug.pow...@aei.com] Sent: Thursday, November 01, 2001 11:38 AM To: EMC-PSTC (E-mail) Subject: EMC test table construction plans Hello all, I plan to construct my own insulated EMC test table for a 5 meter chamber. Seems simple enough to do and I could easily come up with something. I thought I might first ask for input from those of you in the discussion group who have experience or maybe even construction plans. Here are some features I want: 1) I will be testing products that weight up to 200 Lbs (91 kg). 2) I want to minimize metalic fastners. 3) I would like to make it a pivoting table (not motorized). 4) Height is 80 cm. 5) The surface should be replacable if it gets badly worn or scarred. I'm thinking of using hardboard. 6) Suggestions on length width? -doug --- Douglas E. Powell, Compliance Engineer Advanced Energy Industries, Inc. Mail stop: 203024 1626 Sharp Point Drive Ft. Collins, CO 80525 970.407.6410 (phone) 970-407.5410 (fax) mailto:doug.pow...@aei.com --- _ This message, including any attachments, may contain information that is confidential and proprietary information of Advanced Energy Industries, Inc. The dissemination, distribution, use or copying of this message or any of its attachments is strictly prohibited without the express written consent of Advanced Energy Industries, Inc. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
ESD simulators
I like to compile a list of all commercially available ESD simualtors for system level tests to 61000-4-2: In my list I have: KeyTek Minizap KeyTek KeyTek 2000 Schaffner 435 Schaffner 432 EM-TestESD-30c EM-TestESD unit to universal tester UCS 500 EMC-partner TRA 2000 Hotek Tech ESDC - 30 Haefely SESD 200 ESD SIMULATOR SYSTEM Is anyone aware of other models ? Thanks David Pommerenke Associate Professor Electromagnetic Compatibility Laboratory ECE Department University of Missouri-Rolla 1870 Miner Circle Rolla, MO 65409-0040 pommere...@ece.umr.edu Phone: (573) 341-4531 Home: (573) 341 5835 FAX: (573) 341-4532 --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
RE: ESD Immunity Testing
John, Quite true. But on the other side: If a softerror occurs in the field, it is very hard to determine what caused it. Thus, we probably do not know how many ESD-softerrors occur on consumer products in the field. But often there is 'No trouble found' on customer returns. This does not prove that it was ESD. The problem is more the repeatability of test results between companies with an OEM relationship or between different test labs within the same company then field failures. The IEC standard never intended to prevent field failures, e.g., for safety or medical devices there are many discharge possibilities (e.g, Charged Cable Event, furniture ESD, very fast risetimes) that are not covered by the standard, no matter how many discharges one uses. David Pommerenke Associate Professor Electromagnetic Compatibility Laboratory ECE Department University of Missouri-Rolla 1870 Miner Circle Rolla, MO 65409-0040 pommere...@ece.umr.edu Phone: (573) 341-4531 Home: (573) 341 5835 FAX: (573) 341-4532 -Original Message- From: John Woodgate [mailto:j...@jmwa.demon.co.uk] Sent: Friday, September 28, 2001 11:47 AM To: emc-p...@majordomo.ieee.org Subject: Re: ESD Immunity Testing I read in !emc-pstc that wo...@sensormatic.com wrote (in 846BF526A205F8 4BA2B6045BBF7E9A6A43A3C9@flbocexu05) about 'ESD Immunity Testing', on Fri, 28 Sep 2001: So here is my question to those of you involved in the EN/IEC standards - why have these statistical test processes not been acknowledged in the standards? Perhaps because products that pass the tests, however minimal, prove sufficiently immune in practice. I feel sure that if tested products were falling over in the field in large numbers, there would be swift moves to make the test more stringent. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Eat mink and be dreary! --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
RE: ESD Immunity Testing
Richard, Presently, the IEC 61000-4-2 standard is being revised. The main aim of the revision is: Improve the repeatability of test results ! This includes a discussion on the number of discharges. But increasing them is meeting lots or resistance: People simply do not want to increase the test time. To some extend this can be avoided by using a faster rep-rate. But there are failure mechanisms that only show up at faster rates. Thus, if something fails at 20 pulses a second (contact mode) it may not fail at 1 pulse a second. Now a decision has to be made: Is the pass/fail based on the 1 or the 20 Pulse per second result. I think, it should be based on the 1 pulse per second result. In the standard, it is assumed that each pulse is independent of all previous, i.e., that the system has returned to its normal condition from a software and from a electrostatic point of view. There are also other arguments against increasing the number of discharges. - Time dependence of the sensitivity is mainly relevant to soft-errors, but not to hard errors. Thus, if the failure mode at some test point is a harderror, then there would be no reason to apply this statistical method. Even worse, if the ESD hits some sort of a protection circuit it may damage the protection circuit, while in reality, that test point would not see very many ESDs during the life of the product. - The IEC 61000-4-2 standards are basic standards. They do not intend to provide a perfect protection, but only a minimal level. Now one can argue, that using only 10 pulses, the minimal level can not be determined. Thus, using the procedure in the standard, noone can make a decision about pass and fail. - For failure mechanisms related to dielectric breakdown, a different statistical method is needed. But the number of discharges can be much less than a few hundred to obtain good data on the dielectric breakdown probability of a certain air-gap. Many company ESD standards require more discharges than the IEC 61000-4-2 requirement. David Pommerenke Associate Professor Electromagnetic Compatibility Laboratory ECE Department University of Missouri-Rolla 1870 Miner Circle Rolla, MO 65409-0040 pommere...@ece.umr.edu Phone: (573) 341-4531 Home: (573) 341 5835 FAX: (573) 341-4532 -Original Message- From: wo...@sensormatic.com [mailto:wo...@sensormatic.com] Sent: Friday, September 28, 2001 7:28 AM To: emc-p...@majordomo.ieee.org Subject: ESD Immunity Testing Since my last posting on trying to find an ESD expert, I have had to become that expert. After reading the ANSI ESD standard and its references, it is clear that ESD experts are mostly in agreement on how to correctly perform ESD immunity testing. It is also clear test methods in the EN/IEC specifications do not follow that advice. ESD testing is a statistical process, so the test methods and the analysis of the results must be based upon statistics. There are three basic causes. 1) The distribution of ESD events in the operating environment has a non-uniform distribution where the number of expected events per hour is inversely proportional to approximately the square of the voltage. This implies in testing that the number of applied zaps in testing and their levels should also follow this distribution. 2) Digital devices are state machines and some states may be less immune to ESD than other states. This implies that each state should be tested. However, most digital devices have a huge number of states and they change very quickly; therefore, the only way to ensure that even most of the states have been evaluated is to apply a very large number of zap. 3) There may be a probability distribution for the locations on the machine where an ESD discharge is likely to occur. That is, it is not always equally likely that a person or an object will come in contact with any given point on any given surface. Statistics can be used to determine the voltage levels that should be applied and the quantity required at each level in order to provide a specified confidence level that a machine will have no more than a specified number of errors per unit time. However, the number of zaps required is very high, usually in the order of one to ten thousand. The drawback, of course, it that the testing can be time consuming. However, applying in the order of one hundred zaps to a machine according to the EN/IEC specifications will provide such a very, very low confidence level that one cannot reasonably predict the expected error rate in the field. Worst, the results are not repeatable since some states may be tested during one test session and others may be tested during another session. The only predictable case where this might not occur would be with a machine with an ESD robustness level for all states that are far above the actual test levels. So here is my question to those of you involved in the
RE: ESD Testing
Dear Richard, Hewlett Packard tests to more than 15 kV. But please be aware: The severeness of an ESD tests does not always increase with the test voltage. Depending on the physical failure mechanism (energy, current, derivative, fields, E-field, H-field, etc.) it will go down with voltage for air discharge. Testing 15 kV is done for the following reasons: - An environment with a LAREG likelyhood of 15 kV: All mobile environments. Spacecrafts (special case) - Low likelyhood of 15 kV ESDs but an EUT which needs to be very reliable: Medical Safety related - The company wants to ensure that the EUT will pass 8 kV after some years of usage. Changes are: Contamination Cracks in plastic joints etc. Moisture The effect of these parameters on the sparking length are not easy to predict. - The company wants to ensure that it will pass 10 kV at high altidue. Note that the breakdown distance is somewhat 1/proportional to air pressure. If you pass 15 kV in San Diego, you probably pass no more than 10 kV in Denver. - Customer requirement. - To impress the customer. - As a company tradition. In most cases 15 kV testing is done in air discharge. If you are looking not only for survival, but for error-free operation, you should use contact mode testing whereever possible. If you look for error-free operation, it is also very important to test at a lower voltage in contact mode (e.g., 6kV) using a fast risetime simualtor (e.g., 100 ps). There are a larger set of simulators which can do 15 kV. E.g., KeyTek 2000 NoiseKen some Schaffner (not sure) some EM-Test (not sure) Failure criteria depends on the product. David Pommerenke University Missouri-Rolla, 1870 Minor Circle, 118 EECH Rolla, MO 65409-0040 ph: 573 341 4531 home: 573 341 5835 fax: 573 341 4532 email: pommere...@ece.umr.edu -Original Message- From: wo...@sensormatic.com [mailto:wo...@sensormatic.com] Sent: Tuesday, August 14, 2001 8:56 AM To: emc-p...@majordomo.ieee.org Subject: ESD Testing Do any of you perform ESD testing at or above 15 kV to improve product robustness? I have the following questions. o What types of products o What type of user environment o What is the rational for testing above 15 kV o What test equipment is used above 15 kV o What test procedure is used above 15kV o What is the pass/fail criteria above 15 kV Thanks, Richard Woods --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on Virtual Conference Hall, --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.rcic.com/ click on Virtual Conference Hall,
radiated immunity 2 GHz
I upgraded a chamber at hp and looked at: 1) How to pass the 16 point call up to 3 GHz 2) How to upgrade /change add absorbers 3) Which commercial antenna works best from 26 Mhz - 3 GHz 4) How much power is needed. 5) How well does the signal repeat. 6) Field probes 7) etc. The lab is the Hewlett-Packard Roseville Hardware Test Lab. On (2): It turned out that adding absorbers to the floor always spoiled the low frequency (about 80-150MHz) if it improved the high frequency. No matter which absorber type or arrangement on the ferrite-floor tried. But one topology worked very well: Having 5 inch absorbers placed 60 cm above the ground (on a Styrofoam support). Two of those absorbers were placed between the antenna and the turntable. In this arrangement the 16 point cal was passed from 26 MHz to 2.9 GHz (I did not measure any higher). The shadow of the absorber did not reduce the field strength at lower frequencies below 0.8 m height a lot (although there is no regulation on the field strength below 0.8 m). I looked at different log-per antennas (needed power, effect on 16point cal, robustness, weight, handling, SWR, etc.). None of them was a clear winner. Gain wise (judging by needed [power to achieve a certain field strength in this specific chamber), the EMC-Automation antenna was a little a head, but it is also larger and quite heavy. Cable loss is an important factor. Using 25 Watt and having about 3m cable will allow 10 V/m, but there may already be some distortion in the modulation. I think 25 Watts is the minimum for10 V/m from 1 GHz to 3 GHz. Signal reproduction is not that bad, but mechanical positions of absorbers, antenna etc. needs to be controlled very well. All the field probes I tested had some problems. Some did not fulfill their isotropicity specifications, some did not fulfill the frequency response specifications some did not allow the promised number of measurements a second. But for every probe there was a combination of position relative to the field and sampling rate at which it provided good data. If you need any further information, contact me. If you want to use the chamber for immunity testing contact Ken Hall ken_h...@hp.com David Pommerenke University Missouri-Rolla, 1870 Minor Circle, 118 EECH Rolla, MO 65409-0040 ph: 573 341 4531 home: 573 341 5835 fax: 573 341 4532 email: pommere...@ece.umr.edu -Original Message- From: wo...@sensormatic.com [mailto:wo...@sensormatic.com] Sent: Tuesday, August 07, 2001 1:41 PM To: emc-p...@majordomo.ieee.org Subject: RE: ETSI EMC Standard An ETSI representative told me that he thought that most all EU labs have upgraded their chambers and equipment and are now ready to test. That same person asked if the US labs were also ready? Let's hear from both sides of the Atlantic. Are you prepared? Richard Woods -- From: umbdenst...@sensormatic.com [SMTP:umbdenst...@sensormatic.com] Sent: Tuesday, August 07, 2001 1:20 PM To: emc-p...@majordomo.ieee.org Subject: RE: ETSI EMC Standard Regarding the change in the standard, has anyone started to look into an upgrade to their compact chambers for stre-e-e-etching the frequency to 2 GHz? If so, what upgrades did you find most cost effective for * signal generator * amplifier * antenna * sensor * e-field probe * chamber lining modifications Perhaps we can develop a database of options and trade-offs before we need to spend the big bucks. Don Umbdenstock Sensormatic ? -- From: wo...@sensormatic.com[SMTP:wo...@sensormatic.com] Reply To: wo...@sensormatic.com Sent: Tuesday, August 07, 2001 10:15 AM To: emc-p...@majordomo.ieee.org Subject: ETSI EMC Stadard The final draft of the proposed revision of ETSI EN 301 489-1 is in the voting stage. This standard sets the emissions and immunity requirements for most all transmitters. A major change has been made to the radiated immunity requirements by adding the frequencies between 1400 MHz and 2000 MHz. I was told that this change is being driven by CISPR and may be based upon a CISPR standard. Does anyone have any information in this regard? Richard Woods --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send
