RE: 1500 ohms 100 pF gun?
Mike, This is nothing new. Defense (India), it is even wild. IGT goes through same. Sudhakar From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Sosnoski, Michael Sent: Thursday, June 22, 2006 1:10 PM To: emc-p...@ieee.org Subject: RE:1500 ohms 100 pF gun? You guy's are lucky. In gaming --our requirements are Impervious to air discharge of 50Kv and contact at 27Kv. Every time I read of real standards (with any RC network)--I just wish. Mike From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Sudhakar Wasnik Sent: Thursday, June 22, 2006 3:00 PM To: Grasso, Charles; Conway, Patrick R (Houston); John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? Charles, It is not a question of right or wrong. It is about having logical rational explanation. Sudhakar From: Grasso, Charles [mailto:charles.gra...@echostar.com] Sent: Thursday, June 22, 2006 12:55 PM To: Conway, Patrick R (Houston); Sudhakar Wasnik; John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? So - does that mean that only unconventional engineers are right?? :-) Best Regards Charles Grasso Compliance Engineer Echostar Communications Corp. Tel: 303-706-5467 Fax: 303-799-6222 Cell: 303-204-2974 Pager/Short Message: 3032042...@vext.com Email: charles.gra...@echostar.com; Email Alternate: chasgra...@ieee.org From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Conway, Patrick R (Houston) Sent: Thursday, June 22, 2006 1:47 PM To: Sudhakar Wasnik; John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? Ah, ha. Glad to find another engineer who thinks like I do - unconventional! anecdote- One time I visited a large, well respected IT company who was having an ESD problem with a new product. They could not release to production because they could not pass the ESD test. I made one change to their test procedure and they were able to pass. Nothing spectacular really, just a little applied unconventional thinking! I observed that their test engineer was doing the test and then discharging the EUT after each strike (battery operated EUT). The EUT passed each and every strike, but had an upset during his connection of the discharge wire. The discharge wire had no resistors in line. It was a straight dump to the horizontal coupling plane. I explained to the team, showed them the failures were only during post-test charge dump. I explained that the discharge event is uncontrolled. It could have more ore less rise time, more or less fall time, more or less peak amplitude. It is uncontrolled. If they wanted to test with that waveform- no problem. But it is not required for CE Mark (their target). Everyone was happy! Much rejoicing. Anyway- clear evidence that even the post-test discharge needs to be done correctly. And, evidence that more training is always a good thing! Best Regards, Patrick Conway, NCE. 281.514.2259 281.524.5473 (fax) p.con...@hp.com From: Sudhakar Wasnik [mailto:swas...@sandisk.com] Sent: Friday, June 23, 2006 3:14 AM To: Conway, Patrick R (Houston); John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? You are correct sir, The current flow is from higher potential to lower potential. So with repetitive zaps, the system accumulates the charge (potential) higher than Gun potential, So current will flow from Object being zapped to the Gun (Source). That's why standard requires removing the unspent charge from the EUT by manual discharge before applying next zap. If we consider this is same as lightening event, Then John is correct. It is mysterious even to think that the earth (Load) (earth) will pump current in to Clouds (Source) during repetitive lightening strikes. Sudhakar Wasnik Phone. : 408-542-2928 From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Conway, Patrick R (Houston) Sent: Thursday, June 22, 2006 11:15 AM To: John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? q I wonder if Michael would explain how the discharge energy gets back from the equipment being zapped to the source. It seems very mysterious. q Actually, not mysterious at all. But does require some thinking outside of what is considered normal current flow. A simple experiment (real or just a thought experiment) can show the answer. Try this experiment- run a normal ESD test for table top equipment. For this, doesn't matter what test standard. Must use a battery operated EUT. Make sure the EUT power cord is disconnected. Now discharge the ESD simulator to the EUT one time. Discharge works fine, no observable variance in the ESD. But, continue to zap the device. Notice that the observable characteristics
RE:1500 ohms 100 pF gun?
You guy's are lucky. In gaming --our requirements are Impervious to air discharge of 50Kv and contact at 27Kv. Every time I read of real standards (with any RC network)--I just wish. Mike From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Sudhakar Wasnik Sent: Thursday, June 22, 2006 3:00 PM To: Grasso, Charles; Conway, Patrick R (Houston); John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? Charles, It is not a question of right or wrong. It is about having logical rational explanation. Sudhakar From: Grasso, Charles [mailto:charles.gra...@echostar.com] Sent: Thursday, June 22, 2006 12:55 PM To: Conway, Patrick R (Houston); Sudhakar Wasnik; John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? So - does that mean that only unconventional engineers are right?? :-) Best Regards Charles Grasso Compliance Engineer Echostar Communications Corp. Tel: 303-706-5467 Fax: 303-799-6222 Cell: 303-204-2974 Pager/Short Message: 3032042...@vext.com Email: charles.gra...@echostar.com; Email Alternate: chasgra...@ieee.org From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Conway, Patrick R (Houston) Sent: Thursday, June 22, 2006 1:47 PM To: Sudhakar Wasnik; John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? Ah, ha. Glad to find another engineer who thinks like I do - unconventional! anecdote- One time I visited a large, well respected IT company who was having an ESD problem with a new product. They could not release to production because they could not pass the ESD test. I made one change to their test procedure and they were able to pass. Nothing spectacular really, just a little applied unconventional thinking! I observed that their test engineer was doing the test and then discharging the EUT after each strike (battery operated EUT). The EUT passed each and every strike, but had an upset during his connection of the discharge wire. The discharge wire had no resistors in line. It was a straight dump to the horizontal coupling plane. I explained to the team, showed them the failures were only during post-test charge dump. I explained that the discharge event is uncontrolled. It could have more ore less rise time, more or less fall time, more or less peak amplitude. It is uncontrolled. If they wanted to test with that waveform- no problem. But it is not required for CE Mark (their target). Everyone was happy! Much rejoicing. Anyway- clear evidence that even the post-test discharge needs to be done correctly. And, evidence that more training is always a good thing! Best Regards, Patrick Conway, NCE. 281.514.2259 281.524.5473 (fax) p.con...@hp.com From: Sudhakar Wasnik [mailto:swas...@sandisk.com] Sent: Friday, June 23, 2006 3:14 AM To: Conway, Patrick R (Houston); John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? You are correct sir, The current flow is from higher potential to lower potential. So with repetitive zaps, the system accumulates the charge (potential) higher than Gun potential, So current will flow from Object being zapped to the Gun (Source). That's why standard requires removing the unspent charge from the EUT by manual discharge before applying next zap. If we consider this is same as lightening event, Then John is correct. It is mysterious even to think that the earth (Load) (earth) will pump current in to Clouds (Source) during repetitive lightening strikes. Sudhakar Wasnik Phone. : 408-542-2928 From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Conway, Patrick R (Houston) Sent: Thursday, June 22, 2006 11:15 AM To: John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? q I wonder if Michael would explain how the discharge energy gets back from the equipment being zapped to the source. It seems very mysterious. q Actually, not mysterious at all. But does require some thinking outside of what is considered normal current flow. A simple experiment (real or just a thought experiment) can show the answer. Try this experiment- run a normal ESD test for table top equipment. For this, doesn't matter what test standard. Must use a battery operated EUT. Make sure the EUT power cord is disconnected. Now discharge the ESD simulator to the EUT one time. Discharge works fine, no observable variance in the ESD. But, continue to zap the device. Notice that the observable characteristics of the ESD pulses become less severe. Smaller pop sound, plus the simulator tip has to get closer to the device to discharge. Eventually, you can no longer discharge to the EUT. So, what was happening? For all of those discharges what
RE: [JunkMail] 1500 ohms 100 pF gun?
Thank you Sir, I have toughest time of my career explaining this to my co-workers (Mechanical engineers: I apologize for If unknowing I will hurt the feeling of any mechanical engineer) who possess mysterious thinking about ESD. Sudhakar Wasnik From: Conway, Patrick R (Houston) [mailto:p.con...@hp.com] Sent: Thursday, June 22, 2006 12:47 PM To: Sudhakar Wasnik; John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? Ah, ha. Glad to find another engineer who thinks like I do - unconventional! anecdote- One time I visited a large, well respected IT company who was having an ESD problem with a new product. They could not release to production because they could not pass the ESD test. I made one change to their test procedure and they were able to pass. Nothing spectacular really, just a little applied unconventional thinking! I observed that their test engineer was doing the test and then discharging the EUT after each strike (battery operated EUT). The EUT passed each and every strike, but had an upset during his connection of the discharge wire. The discharge wire had no resistors in line. It was a straight dump to the horizontal coupling plane. I explained to the team, showed them the failures were only during post-test charge dump. I explained that the discharge event is uncontrolled. It could have more ore less rise time, more or less fall time, more or less peak amplitude. It is uncontrolled. If they wanted to test with that waveform- no problem. But it is not required for CE Mark (their target). Everyone was happy! Much rejoicing. Anyway- clear evidence that even the post-test discharge needs to be done correctly. And, evidence that more training is always a good thing! Best Regards, Patrick Conway, NCE. 281.514.2259 281.524.5473 (fax) p.con...@hp.com From: Sudhakar Wasnik [mailto:swas...@sandisk.com] Sent: Friday, June 23, 2006 3:14 AM To: Conway, Patrick R (Houston); John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? You are correct sir, The current flow is from higher potential to lower potential. So with repetitive zaps, the system accumulates the charge (potential) higher than Gun potential, So current will flow from Object being zapped to the Gun (Source). That's why standard requires removing the unspent charge from the EUT by manual discharge before applying next zap. If we consider this is same as lightening event, Then John is correct. It is mysterious even to think that the earth (Load) (earth) will pump current in to Clouds (Source) during repetitive lightening strikes. Sudhakar Wasnik Phone. : 408-542-2928 From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Conway, Patrick R (Houston) Sent: Thursday, June 22, 2006 11:15 AM To: John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? q I wonder if Michael would explain how the discharge energy gets back from the equipment being zapped to the source. It seems very mysterious. q Actually, not mysterious at all. But does require some thinking outside of what is considered normal current flow. A simple experiment (real or just a thought experiment) can show the answer. Try this experiment- run a normal ESD test for table top equipment. For this, doesn't matter what test standard. Must use a battery operated EUT. Make sure the EUT power cord is disconnected. Now discharge the ESD simulator to the EUT one time. Discharge works fine, no observable variance in the ESD. But, continue to zap the device. Notice that the observable characteristics of the ESD pulses become less severe. Smaller pop sound, plus the simulator tip has to get closer to the device to discharge. Eventually, you can no longer discharge to the EUT. So, what was happening? For all of those discharges what was the Return path, since the EUT cord was removed? Why is it that the simulator no longer discharges? Those last two questions have the same answer. Maybe the normal loop model, source-destination-return-to-source, does not apply? Hmm. Best Regards, Patrick Conway, NCE. 281.514.2259 281.524.5473 (fax) p.con...@hp.com - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim
RE: [JunkMail] 1500 ohms 100 pF gun?
Charles, It is not a question of right or wrong. It is about having logical rational explanation. Sudhakar From: Grasso, Charles [mailto:charles.gra...@echostar.com] Sent: Thursday, June 22, 2006 12:55 PM To: Conway, Patrick R (Houston); Sudhakar Wasnik; John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? So - does that mean that only unconventional engineers are right?? :-) Best Regards Charles Grasso Compliance Engineer Echostar Communications Corp. Tel: 303-706-5467 Fax: 303-799-6222 Cell: 303-204-2974 Pager/Short Message: 3032042...@vext.com Email: charles.gra...@echostar.com; Email Alternate: chasgra...@ieee.org From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Conway, Patrick R (Houston) Sent: Thursday, June 22, 2006 1:47 PM To: Sudhakar Wasnik; John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? Ah, ha. Glad to find another engineer who thinks like I do - unconventional! anecdote- One time I visited a large, well respected IT company who was having an ESD problem with a new product. They could not release to production because they could not pass the ESD test. I made one change to their test procedure and they were able to pass. Nothing spectacular really, just a little applied unconventional thinking! I observed that their test engineer was doing the test and then discharging the EUT after each strike (battery operated EUT). The EUT passed each and every strike, but had an upset during his connection of the discharge wire. The discharge wire had no resistors in line. It was a straight dump to the horizontal coupling plane. I explained to the team, showed them the failures were only during post-test charge dump. I explained that the discharge event is uncontrolled. It could have more ore less rise time, more or less fall time, more or less peak amplitude. It is uncontrolled. If they wanted to test with that waveform- no problem. But it is not required for CE Mark (their target). Everyone was happy! Much rejoicing. Anyway- clear evidence that even the post-test discharge needs to be done correctly. And, evidence that more training is always a good thing! Best Regards, Patrick Conway, NCE. 281.514.2259 281.524.5473 (fax) p.con...@hp.com From: Sudhakar Wasnik [mailto:swas...@sandisk.com] Sent: Friday, June 23, 2006 3:14 AM To: Conway, Patrick R (Houston); John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? You are correct sir, The current flow is from higher potential to lower potential. So with repetitive zaps, the system accumulates the charge (potential) higher than Gun potential, So current will flow from Object being zapped to the Gun (Source). That's why standard requires removing the unspent charge from the EUT by manual discharge before applying next zap. If we consider this is same as lightening event, Then John is correct. It is mysterious even to think that the earth (Load) (earth) will pump current in to Clouds (Source) during repetitive lightening strikes. Sudhakar Wasnik Phone. : 408-542-2928 From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Conway, Patrick R (Houston) Sent: Thursday, June 22, 2006 11:15 AM To: John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? q I wonder if Michael would explain how the discharge energy gets back from the equipment being zapped to the source. It seems very mysterious. q Actually, not mysterious at all. But does require some thinking outside of what is considered normal current flow. A simple experiment (real or just a thought experiment) can show the answer. Try this experiment- run a normal ESD test for table top equipment. For this, doesn't matter what test standard. Must use a battery operated EUT. Make sure the EUT power cord is disconnected. Now discharge the ESD simulator to the EUT one time. Discharge works fine, no observable variance in the ESD. But, continue to zap the device. Notice that the observable characteristics of the ESD pulses become less severe. Smaller pop sound, plus the simulator tip has to get closer to the device to discharge. Eventually, you can no longer discharge to the EUT. So, what was happening? For all of those discharges what was the Return path, since the EUT cord was removed? Why is it that the simulator no longer discharges? Those last two questions have the same answer. Maybe the normal loop model, source-destination-return-to-source, does not apply? Hmm. Best Regards, Patrick Conway, NCE. 281.514.2259 281.524.5473 (fax) p.con...@hp.com - This message is from the IEEE Product Safety Engineering Society
RE: [JunkMail] 1500 ohms 100 pF gun?
So - does that mean that only unconventional engineers are right?? :-) Best Regards Charles Grasso Compliance Engineer Echostar Communications Corp. Tel: 303-706-5467 Fax: 303-799-6222 Cell: 303-204-2974 Pager/Short Message: 3032042...@vext.com Email: charles.gra...@echostar.com; Email Alternate: chasgra...@ieee.org From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Conway, Patrick R (Houston) Sent: Thursday, June 22, 2006 1:47 PM To: Sudhakar Wasnik; John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? Ah, ha. Glad to find another engineer who thinks like I do - unconventional! anecdote- One time I visited a large, well respected IT company who was having an ESD problem with a new product. They could not release to production because they could not pass the ESD test. I made one change to their test procedure and they were able to pass. Nothing spectacular really, just a little applied unconventional thinking! I observed that their test engineer was doing the test and then discharging the EUT after each strike (battery operated EUT). The EUT passed each and every strike, but had an upset during his connection of the discharge wire. The discharge wire had no resistors in line. It was a straight dump to the horizontal coupling plane. I explained to the team, showed them the failures were only during post-test charge dump. I explained that the discharge event is uncontrolled. It could have more ore less rise time, more or less fall time, more or less peak amplitude. It is uncontrolled. If they wanted to test with that waveform- no problem. But it is not required for CE Mark (their target). Everyone was happy! Much rejoicing. Anyway- clear evidence that even the post-test discharge needs to be done correctly. And, evidence that more training is always a good thing! Best Regards, Patrick Conway, NCE. 281.514.2259 281.524.5473 (fax) p.con...@hp.com From: Sudhakar Wasnik [mailto:swas...@sandisk.com] Sent: Friday, June 23, 2006 3:14 AM To: Conway, Patrick R (Houston); John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? You are correct sir, The current flow is from higher potential to lower potential. So with repetitive zaps, the system accumulates the charge (potential) higher than Gun potential, So current will flow from Object being zapped to the Gun (Source). That's why standard requires removing the unspent charge from the EUT by manual discharge before applying next zap. If we consider this is same as lightening event, Then John is correct. It is mysterious even to think that the earth (Load) (earth) will pump current in to Clouds (Source) during repetitive lightening strikes. Sudhakar Wasnik Phone. : 408-542-2928 From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Conway, Patrick R (Houston) Sent: Thursday, June 22, 2006 11:15 AM To: John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? q I wonder if Michael would explain how the discharge energy gets back from the equipment being zapped to the source. It seems very mysterious. q Actually, not mysterious at all. But does require some thinking outside of what is considered normal current flow. A simple experiment (real or just a thought experiment) can show the answer. Try this experiment- run a normal ESD test for table top equipment. For this, doesn't matter what test standard. Must use a battery operated EUT. Make sure the EUT power cord is disconnected. Now discharge the ESD simulator to the EUT one time. Discharge works fine, no observable variance in the ESD. But, continue to zap the device. Notice that the observable characteristics of the ESD pulses become less severe. Smaller pop sound, plus the simulator tip has to get closer to the device to discharge. Eventually, you can no longer discharge to the EUT. So, what was happening? For all of those discharges what was the Return path, since the EUT cord was removed? Why is it that the simulator no longer discharges? Those last two questions have the same answer. Maybe the normal loop model, source-destination-return-to-source, does not apply? Hmm. Best Regards, Patrick Conway, NCE. 281.514.2259 281.524.5473 (fax) p.con...@hp.com - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas
RE: 1500 ohms 100 pF gun?
My bet's on capacitance Interesting thread --- kinda like déjà vu -- all these same conversations went on back in the mid 80's. Back then, there were lot's of specifications for ESD --- everyone had their own idea of what the capacitance and resistance values should be for a human discharge, with or without metal attached.. This settled into the IEC 801-2 values over time, but meanwhile, gun manufacturers made every version of discharge network known to man, from 20pf to 1000pf and from 0 ohms to 5k ohms IBM had a special tester (it was a secret at the time), that did high repetition rate testing and was coupled to radiating planes Wild stuff... I think they may still have some they'd sell cheap The Andy Hisch gun was very popular, and a lot of corporate standards were written around it, inlcuding those for companies like DEC and HP --- International standards took over eventually and the standardization began, which eventually forced most to the IEC model; however, other standards still exist -- most importantly for automotive and military. Not to mention device level testing that uses even different models. My 2 cents. Best Regards, Michael Hopkins Manager, Customer Technical Center Process Instruments Division Thermo Electron Corporation One Lowell Research Center Lowell, MA 01852 Tel: +1 978 935 9334 Direct +1 978 275 0800 Main +1 603 765 3736 Mobile michael.hopk...@thermo.com www.thermo.com/esd From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of John Woodgate Sent: Thursday, June 22, 2006 1:39 PM To: emc-p...@ieee.org Subject: Re: 1500 ohms 100 pF gun? In message 000801c69620$35d095e0$150bb...@colorado.linear.com, dated Thu, 22 Jun 2006, David Cuthbert dcuthb...@linear.com writes The return path for the charge (from the floating person) must be through displacement current. Oh, it IS magic, then. (;-) -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk 2006 is YMMVI- Your mileage may vary immensely. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: [JunkMail] 1500 ohms 100 pF gun?
Ah, ha. Glad to find another engineer who thinks like I do - unconventional! anecdote- One time I visited a large, well respected IT company who was having an ESD problem with a new product. They could not release to production because they could not pass the ESD test. I made one change to their test procedure and they were able to pass. Nothing spectacular really, just a little applied unconventional thinking! I observed that their test engineer was doing the test and then discharging the EUT after each strike (battery operated EUT). The EUT passed each and every strike, but had an upset during his connection of the discharge wire. The discharge wire had no resistors in line. It was a straight dump to the horizontal coupling plane. I explained to the team, showed them the failures were only during post-test charge dump. I explained that the discharge event is uncontrolled. It could have more ore less rise time, more or less fall time, more or less peak amplitude. It is uncontrolled. If they wanted to test with that waveform- no problem. But it is not required for CE Mark (their target). Everyone was happy! Much rejoicing. Anyway- clear evidence that even the post-test discharge needs to be done correctly. And, evidence that more training is always a good thing! Best Regards, Patrick Conway, NCE. 281.514.2259 281.524.5473 (fax) p.con...@hp.com From: Sudhakar Wasnik [mailto:swas...@sandisk.com] Sent: Friday, June 23, 2006 3:14 AM To: Conway, Patrick R (Houston); John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? You are correct sir, The current flow is from higher potential to lower potential. So with repetitive zaps, the system accumulates the charge (potential) higher than Gun potential, So current will flow from Object being zapped to the Gun (Source). That's why standard requires removing the unspent charge from the EUT by manual discharge before applying next zap. If we consider this is same as lightening event, Then John is correct. It is mysterious even to think that the earth (Load) (earth) will pump current in to Clouds (Source) during repetitive lightening strikes. Sudhakar Wasnik Phone. : 408-542-2928 From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Conway, Patrick R (Houston) Sent: Thursday, June 22, 2006 11:15 AM To: John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? q I wonder if Michael would explain how the discharge energy gets back from the equipment being zapped to the source. It seems very mysterious. q Actually, not mysterious at all. But does require some thinking outside of what is considered normal current flow. A simple experiment (real or just a thought experiment) can show the answer. Try this experiment- run a normal ESD test for table top equipment. For this, doesn't matter what test standard. Must use a battery operated EUT. Make sure the EUT power cord is disconnected. Now discharge the ESD simulator to the EUT one time. Discharge works fine, no observable variance in the ESD. But, continue to zap the device. Notice that the observable characteristics of the ESD pulses become less severe. Smaller pop sound, plus the simulator tip has to get closer to the device to discharge. Eventually, you can no longer discharge to the EUT. So, what was happening? For all of those discharges what was the Return path, since the EUT cord was removed? Why is it that the simulator no longer discharges? Those last two questions have the same answer. Maybe the normal loop model, source-destination-return-to-source, does not apply? Hmm. Best Regards, Patrick Conway, NCE. 281.514.2259 281.524.5473 (fax) p.con...@hp.com - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions:
RE: [JunkMail] 1500 ohms 100 pF gun?
You are correct sir, The current flow is from higher potential to lower potential. So with repetitive zaps, the system accumulates the charge (potential) higher than Gun potential, So current will flow from Object being zapped to the Gun (Source). That's why standard requires removing the unspent charge from the EUT by manual discharge before applying next zap. If we consider this is same as lightening event, Then John is correct. It is mysterious even to think that the earth (Load) (earth) will pump current in to Clouds (Source) during repetitive lightening strikes. Sudhakar Wasnik Phone. : 408-542-2928 From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Conway, Patrick R (Houston) Sent: Thursday, June 22, 2006 11:15 AM To: John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? q I wonder if Michael would explain how the discharge energy gets back from the equipment being zapped to the source. It seems very mysterious. q Actually, not mysterious at all. But does require some thinking outside of what is considered normal current flow. A simple experiment (real or just a thought experiment) can show the answer. Try this experiment- run a normal ESD test for table top equipment. For this, doesn't matter what test standard. Must use a battery operated EUT. Make sure the EUT power cord is disconnected. Now discharge the ESD simulator to the EUT one time. Discharge works fine, no observable variance in the ESD. But, continue to zap the device. Notice that the observable characteristics of the ESD pulses become less severe. Smaller pop sound, plus the simulator tip has to get closer to the device to discharge. Eventually, you can no longer discharge to the EUT. So, what was happening? For all of those discharges what was the Return path, since the EUT cord was removed? Why is it that the simulator no longer discharges? Those last two questions have the same answer. Maybe the normal loop model, source-destination-return-to-source, does not apply? Hmm. Best Regards, Patrick Conway, NCE. 281.514.2259 281.524.5473 (fax) p.con...@hp.com - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: CISPR22 Edition 5 SLCE and Ethernet
John, Many thanks for helping getting a reply form the source. I mostly appreciate it. Neven -- Original message -- From: John Woodgate j...@jmwa.demon.co.uk In message 062220060603.17444.449A32C1000E06B844242207020853CECE020A900A02@comc ast.net, dated Thu, 22 Jun 2006, neve...@comcast.net writes AFAIK, there is no spec on imbalance of (each diff pair of) a port, and I will check it with my local IEEE Ethernet spec specialists. I don't know if there is a spec on the cable, but I will try to find it. I'd really like to see if the requirement from the standard has any basis in the actual real-world measurements. Specially for you, I asked my standards committee colleague Martin Wright, who is Chairman of CISPR/I, and his reply is: It is quite correct that CISPR 22 is trying to emulate the performa! nce of cabled installations. The effect of installations on LCL remains an open question. At the time that this part of CISPR 22 was written, many attempts were made to obtain data on LCL of installations from telecomms and ITE installers but the relative performance of installations from an LCL perspective was (and still is) seen as 'sensitive' data and was never released to the standards bodies. The LCL values in CISPR 22 were based on a series of measurements made by Telstra in Australia along with private inputs from some of the telcos represented in the working group (NTT, BT, FT and Telia). This data was circulated to both ITU and ETSI with a question 'Does the LCL shown in these curves form a reasonable representation of the installed LCL of the cabling base in your country' and this did elicit some responses. The curves were then re! -aligne d with this information. From the perspective of the UK, I know that there was a major analysis of the Telecomms network at this time which showed that very few lines were worse than the LCL specified. This result implies that the radio spectrum will receive better protection (in most cases) than these values would suggest. This has the corollary that the emissions from the system could potentially be higher than the limits allow with no adverse affects. Against this background we also need to consider the wireline proposals where the radio users are pushing for limits at least 20dB below the CISPR limits in order to better protect the radio spectrum. It would be very difficult to write a valid definition of wireline which did not include Ethernet, 10base T etc. These two facts (maybe) imply that the CISPR limit is an OK compromise ?! g t; The current/voltage measurement in CISPR 22 comes from a completely different approach where the interest is in the power emitted, wherever it comes from, which also has much support in CISPR I. This only consider LCL in the indirect way that some of the power emitted will come from the LCL conversion. As a final point the issue of LCL specification is certainly not closed in CISPR I. There is a current active liaison with cable and installation groups (TC46X, ISO/IEC JTC 1 WG 25 and so on) to better understand the LCL and installation issues. I hope this helps to give the background to the requirements but please note that I am condensing nearly 15 years of development into this short email so may well have missed something significant. Regards Martin Wright, Chairman CISPR I Contact details fo! r Marti n are at:http://tinyurl.com/loy3x -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk 2006 is YMMVI- Your mileage may vary immensely. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bacher! @ieee.o rg David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For
RE: [JunkMail] 1500 ohms 100 pF gun?
q I wonder if Michael would explain how the discharge energy gets back from the equipment being zapped to the source. It seems very mysterious. q Actually, not mysterious at all. But does require some thinking outside of what is considered normal current flow. A simple experiment (real or just a thought experiment) can show the answer. Try this experiment- run a normal ESD test for table top equipment. For this, doesn't matter what test standard. Must use a battery operated EUT. Make sure the EUT power cord is disconnected. Now discharge the ESD simulator to the EUT one time. Discharge works fine, no observable variance in the ESD. But, continue to zap the device. Notice that the observable characteristics of the ESD pulses become less severe. Smaller pop sound, plus the simulator tip has to get closer to the device to discharge. Eventually, you can no longer discharge to the EUT. So, what was happening? For all of those discharges what was the Return path, since the EUT cord was removed? Why is it that the simulator no longer discharges? Those last two questions have the same answer. Maybe the normal loop model, source-destination-return-to-source, does not apply? Hmm. Best Regards, Patrick Conway, NCE. 281.514.2259 281.524.5473 (fax) p.con...@hp.com - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: German Power Cord Info Request
In message ofcbd6f238.bf10c5dd-on85257195.006031f0-85257195.0060b...@hobartcorp.com , dated Thu, 22 Jun 2006, Richard Pittenger richard.pitten...@hobartcorp.com writes Hello Group, This may be a long shot, but I'm searching for information/specifications, etc., concerning German power cordage for a kitchen appliance. One spec. is VDE 02050 I think that may be VDE 0250, which can be found at: http://tinyurl.com/z5jjk and the other is VDE 0293. The Beuth web site isn't fully compatible with Tiny URL; any search result page translates to the same TinyURL. So you need to enter 'VDE0293' (no spaces!) in the search box on the page that gives you the VDE0250 data. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk 2006 is YMMVI- Your mileage may vary immensely. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
German Power Cord Info Request
Hello Group, This may be a long shot, but I'm searching for information/specifications, etc., concerning German power cordage for a kitchen appliance. One spec. is VDE 02050 and the other is VDE 0293. I'm not sure if these VDE numbers relate to product standards, cord construction or just what these references deal with. Any help you can provide to help define what these specs. mean will be appreciated. Good day, Richard I. Pittenger Agency Approval Engineer Food Retail Div. Hobart Troy, Ohio 45374 - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: 1500 ohms 100 pF gun?
In message 000801c69620$35d095e0$150bb...@colorado.linear.com, dated Thu, 22 Jun 2006, David Cuthbert dcuthb...@linear.com writes The return path for the charge (from the floating person) must be through displacement current. Oh, it IS magic, then. (;-) -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk 2006 is YMMVI- Your mileage may vary immensely. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: 1500 ohms 100 pF gun?
Brent, I ran measurements a couple of years ago with myself discharging into a 2-ohm ESD target. I got the same results as sited in the email. A metal object in the hand really kicks up the initial current. The initial 300 ohm source appeared to be the arm followed by the body as 1200 ohms. SPICE was able to accurately model all of this. The human current rise time was faster than what our 3 GHz oscilloscope could measure. I would like to repeat these measurements using a 12 GHz oscilloscope. I did build a generator that accurately mimics the human waveforms using a bunch of leaded inductors and SMT caps and resistors. The return path for the charge (from the floating person) must be through displacement current. Dave Cuthbert Senior Test Engineer Linear Technology, Colorado Design Center NARTE Certified EMC Engineer, IEEE Member From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Brent DeWitt Sent: Thursday, June 22, 2006 9:47 AM To: Cortland Richmond; ieee pstc list Subject: Re: 1500 ohms 100 pF gun? I don't know about the Hish gun, but you can put that network together in a NoiseKen ESS-2000. The cap and resistor values are independently user changable. Brent DeWitt Everett, WA From: Cortland Richmond 72146@compuserve.com Sent: Jun 21, 2006 4:38 AM To: ieee pstc list emc-p...@ieee.org Subject: 1500 ohms 100 pF gun? Was looking for one for some military testing at work. I seem to recall that the Andy Hish ESD-255 used this network in one of its probes. Am I wrong? Cortland Richmond KA5S - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: 1500 ohms 100 pF gun?
I don't know about the Hish gun, but you can put that network together in a NoiseKen ESS-2000. The cap and resistor values are independently user changable. Brent DeWitt Everett, WA From: Cortland Richmond 72146@compuserve.com Sent: Jun 21, 2006 4:38 AM To: ieee pstc list emc-p...@ieee.org Subject: 1500 ohms 100 pF gun? Was looking for one for some military testing at work. I seem to recall that the Andy Hish ESD-255 used this network in one of its probes. Am I wrong? Cortland Richmond KA5S - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Power in European data centers
APC sells a number of power distribution products world wide. All of our European products are for 230 V phase-to-neutral loads. I have not run into any 400 V phase-to-phase loads. The 400 V loads commonly used are three-phase 400 V support products such as air conditioners. Although power consumption of equipment is increasing leading to higher currents, I would not expect 400 V input equipment any time soon. There would need to be significant changes to the power supplies to support the higher voltage. However, there is now research underway to go a different direction: DC power distribution. http://hightech.lbl.gov/dc-powering/about.html http://www.energy.ca.gov/releases/2002_releases/2002-03-01_server_farms_nr.html Ted Eckert American Power Conversion Corporation The items contained in this e-mail reflect the personal opinions of the writer and are only provided for the assistance of the reader. The writer is not speaking in an official capacity for APC nor representing APC's official position on any matter. McInturff Gary GMcInturff@spray cool.com To Sent by: emc-p...@ieee.org emc-p...@ieee.org cc Subject 06/22/2006 10:32 Power in European data centers AM Good people In the US its typical for a large data center to run 208 Vac rather than 120 Vac, and I just want to confirm I’m not going to run into a similar change of voltage in European data centers. I assume that there is no switch from 230 Vac, 50 Hz and phase to neutral. Thanks Gary - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: [JunkMail] 1500 ohms 100 pF gun?
Hi All, Michael tried to respond but not being a member of the list, his reply bounced. I have forwarded it below. Doug From Michael King: Greetings, When we (David Reynolds, Andy Hish and myself) determined the waveforms of ESD, we researched several typical applications: Human finger-tip direct; Humans with small metallic intervening objects (e.g. keys, coins, pens); and, Humans with large mobile furnishings (e.g. chairs and push carts). Our intention was to present the concept that probes that would replicate these events, would be applied to products where the specific type of contact would be prevalent. Keyboards, for example, would be typical of finger-tip events; areas with supervisor locks requiring keys (such as on POS terminals) would receive the humans-metal-object events; and some regions where a cart (e.g. grocery cart) would be tested with that much higher current replication. As is universally recognized today, we discovered that there were two essential characteristics to the ESD event: an early event with a very low source impedance; and, a trailing event with a higher impedance. (I'm using the terms we had in our private discussions together circa 1979.) The early event for human finger-tip direct has a typical source impedance of about 200 Ohms, with the trailing event having a total source impedance of about 1,200 Ohms. The early event for humans with a small metallic object is about 20 Ohms with the trailing event about 420 Ohms. Desk chairs and push carts tend to exhibit source impedances in the early event of about 10 Ohms, and for the whole of the event about 50 to 75 Ohms. So, Andy Hish who was successful in producing a test generator that essentially replicated these events even as they shifted waveforms at various ESD amplitudes (I have the historical data) decided to assign probes for his ESD-255 as: P-255-0 for the finger tip event; P-255-1 for the human/metal object event; and, P-255-3 for the furnishings event. When we revealed our results to various corporations circa 1980, the landslide of interest from management was only for the P-255-1 probe, with a few having interest also in the P-255-3 probe. To the best of my knowledge, only ONE P-255-0 probe was ever produced, and that one was the full-build prototype that we used to verify that the replication for that condition could be achieved. That probe was lost to history decades ago. We later collaborated with Peter Richman, then V-P of engineering and founder of KeyTek, and he had assigned various DN numbers for probes of his true ESD K2020 (by memory) test set. The DN-10, I seem to remember, was for the human metal/object probe, and although he knew of our numbers for the finger tip probe, to the best of my knowledge as was in the case with Andy Hish, no one ever ordered the finger-tip equivalent probe from him as well. BTW, the construction of the finger-tip probe is quite tricky because of the distribution of the distributed capacitance field source for the early event. While it was possible to adapt Andy Hish's P-255-1 probe (by Andy's internal processes) to the ~3x higher resistance numbers that were in the multiple element distributed line (that looked like a probe externally), the 200 Ohms early event we found could only be replicated by something like a resistively lossy, graphite impregnated, hemisphere at the tip of the probe, presenting a diameter of about 5cm on the major axis and the depth of about 2cm on the minor axis, with the graphite saturation set to about 200 to 300 Ohms/square when measured on the surface. Michael At 06:11 PM 6/21/2006, Doug Smith wrote: Hi Cortland and the group (from vacation in Orange County, CA), I remember using such a network in a home built ESD simulator many years ago at Bell Labs, a human finger model. Electronic telephones that had no problem with such a simulator did not come back for warrantee repairs. The IEC network, which models a piece of metal in the hand, is much more severe and is often an overtest of small plastic items like telephones and PDAs. I have copied Michael King on this. He is an early pioneer in ESD and perhaps can shed some light on this in addition to what I have said above. Much of what we now do in ESD was laid out by Michael decades ago and is still valid. Doug Cortland Richmond wrote: Was looking for one for some military testing at work. I seem to recall that the Andy Hish ESD-255 used this network in one of its probes. Am I wrong? Cortland Richmond KA5S - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas
Power in European data centers
Good people In the US its typical for a large data center to run 208 Vac rather than 120 Vac, and I just want to confirm I’m not going to run into a similar change of voltage in European data centers. I assume that there is no switch from 230 Vac, 50 Hz and phase to neutral. Thanks Gary - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: CISPR22 Edition 5 SLCE and Ethernet
In message 062220060603.17444.449A32C1000E06B844242207020853CECE020A900A02@comc ast.net, dated Thu, 22 Jun 2006, neve...@comcast.net writes AFAIK, there is no spec on imbalance of (each diff pair of) a port, and I will check it with my local IEEE Ethernet spec specialists. I don't know if there is a spec on the cable, but I will try to find it. I'd really like to see if the requirement from the standard has any basis in the actual real-world measurements. Specially for you, I asked my standards committee colleague Martin Wright, who is Chairman of CISPR/I, and his reply is: It is quite correct that CISPR 22 is trying to emulate the performance of cabled installations. The effect of installations on LCL remains an open question. At the time that this part of CISPR 22 was written, many attempts were made to obtain data on LCL of installations from telecomms and ITE installers but the relative performance of installations from an LCL perspective was (and still is) seen as 'sensitive' data and was never released to the standards bodies. The LCL values in CISPR 22 were based on a series of measurements made by Telstra in Australia along with private inputs from some of the telcos represented in the working group (NTT, BT, FT and Telia). This data was circulated to both ITU and ETSI with a question 'Does the LCL shown in these curves form a reasonable representation of the installed LCL of the cabling base in your country' and this did elicit some responses. The curves were then re-aligned with this information. From the perspective of the UK, I know that there was a major analysis of the Telecomms network at this time which showed that very few lines were worse than the LCL specified. This result implies that the radio spectrum will receive better protection (in most cases) than these values would suggest. This has the corollary that the emissions from the system could potentially be higher than the limits allow with no adverse affects. Against this background we also need to consider the wireline proposals where the radio users are pushing for limits at least 20dB below the CISPR limits in order to better protect the radio spectrum. It would be very difficult to write a valid definition of wireline which did not include Ethernet, 10base T etc. These two facts (maybe) imply that the CISPR limit is an OK compromise ? The current/voltage measurement in CISPR 22 comes from a completely different approach where the interest is in the power emitted, wherever it comes from, which also has much support in CISPR I. This only consider LCL in the indirect way that some of the power emitted will come from the LCL conversion. As a final point the issue of LCL specification is certainly not closed in CISPR I. There is a current active liaison with cable and installation groups (TC46X, ISO/IEC JTC 1 WG 25 and so on) to better understand the LCL and installation issues. I hope this helps to give the background to the requirements but please note that I am condensing nearly 15 years of development into this short email so may well have missed something significant. Regards Martin Wright, Chairman CISPR I Contact details for Martin are at:http://tinyurl.com/loy3x -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk 2006 is YMMVI- Your mileage may vary immensely. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: China mandatory certification for WLAN
The CNCA-11C-048 is an implementation rule for WLAN. CNCA doesn't issue an English version after the first 47 implementations. There is no official English version for this implementation rule. An easy and cheap way is to find a Chinese colleague or friend around you to explain what inside there. Every implementation rule has a similar format. You can download any English version of implementation rule ( http:/ www.cnca.gov.cn/col227/index.htm1?id=227, not for CNCA-11C-048 ) to get an idea how the format is. The main concern you may have is the protocol. If you need more detail, take a look at http://www.evaluationengineer ng.com/archive/articles/0804/0804emc_app.asp . You can download GB standards from SAC referred link. Download instruction can be found at www.graspllc.com, under Resources. I hope this helps. Best regards, Grace On 6/22/06, KYAW HTIN AUNG kyaw_h...@yahoo.com wrote: Dear All China re-invokes this mandatory certification for WLAN product. The document is CNCA-11C-048 and can be downloaded from CNCA website. Anybody have English translation? Or anybody can show where to get it? Thanks and Regards Kyaw Senior Regulatory Engineer Olympus Technologies ___ Try the all-new Yahoo! Mail. The New Version is radically easier to use – The Wall Street Journal http://uk.docs.yahoo.com/nowyoucan.html - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglasmailto:emcp...@ptcnh.net emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: mailto:j.bac...@ieee.org j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
China mandatory certification for WLAN
Dear All China re-invokes this mandatory certification for WLAN product. The document is CNCA-11C-048 and can be downloaded from CNCA website. Anybody have English translation? Or anybody can show where to get it? Thanks and Regards Kyaw Senior Regulatory Engineer Olympus Technologies ___ Try the all-new Yahoo! Mail. The New Version is radically easier to use – The Wall Street Journal http://uk.docs.yahoo.com/nowyoucan.html - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: CISPR22 Edition 5 SLCE and Ethernet
AFAIK, there is no spec on imbalance of (each diff pair of) a port, and I will check it with my local IEEE Ethernet spec specialists. I don't know if there is a spec on the cable, but I will try to find it. I'd really like to see if the requirement from the standard has any basis in the actual real-world measurements. Neven -- Original message -- From: John Woodgate j...@jmwa.demon.co.uk When you do that, you see the combined effect of the cable impedances and the impedances of the port at the far end. So the LCL can be calculated from the specifications (if they exist) of those impedances or equivalent data. Maybe that is what was done in order to get the LCL figures specified in CISPR 22. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: CISPR22 Edition 5 SLCE and Ethernet
In message 062220060528.732.449A2A99000B117902DC2200745672CECE020A900A02@comcas t.net, dated Thu, 22 Jun 2006, neve...@comcast.net writes However, the issue is not the imbalance specification looking into the DUT connector (test port, diff pairs). The problem that I see here is that CISPR22, 2005 is trying to emulate the imbalance of the Typical installation, and that I do not find any measurement data on that, at least not for the CAT3-7 cabling. I do find the LCL (i.e. balance) vs. frequency information in standards, but absolutely no published data on LCL of typical installations to support them. So, I don't know where these values in the standards are coming from. In a 'typical installation', the cable is connected to a port at each end. Again, I am not talking here about imbalance at the DUT connector, but imbalance that appears looking into the cabling from the DUT. When you do that, you see the combined effect of the cable impedances and the impedances of the port at the far end. So the LCL can be calculated from the specifications (if they exist) of those impedances or equivalent data. Maybe that is what was done in order to get the LCL figures specified in CISPR 22. The required level of imbalance for the ISN, combined with the max possible (although not always used) amplitude of 10 BaseT (5.6 Vpk-pk) makes me uncomfortable. On the other hand, if one uses the method with current and voltage clamp, then there is no requirement for LCL, since the measurement is done on the cable without any ISN. In my opinion, manufacturers of Class B products that use Ethernet, e.g. laptops, PCs, SOHO routers/switches) should be concerned by the still (in my opinion) not well defined requirements. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk 2006 is YMMVI- Your mileage may vary immensely. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: CISPR22 Edition 5 SLCE and Ethernet
John, thanks for the explanation to David, you are right in what you wrote. I was out the whole day so I am catching up now in the evening. However, the issue is not the imbalance specification looking into the DUT connector (test port, diff pairs). The problem that I see here is that CISPR22, 2005 is trying to emulate the imbalance of the Typical installation, and that I do not find any measurement data on that, at least not for the CAT3-7 cabling. I do find the LCL (i.e. balance) vs. frequency information in standards, but absolutely no published data on LCL of typical installations to support them. So, I don't know where these values in the standards are coming from. Again, I am not talking here about imbalance at the DUT connector, but imbalance that appears looking into the cabling from the DUT. The required level of imbalance for the ISN, combined with the max possible (although not always used) amplitude of 10 BaseT (5.6 Vpk-pk) makes me uncomfortable. On the other hand, if one uses the method with current and voltage clamp, then there is no requirement for LCL, since the measurement is done on the cable without any ISN. In my opinion, manufacturers of Class B products that use Ethernet, e.g. laptops, PCs, SOHO routers/switches) should be concerned by the still (in my opinion) not well defined requirements. Neven - Original message -- From: John Woodgate j...@jmwa.demon.co.uk I'm not sure what you mean by 'an impedance imbalance between the two ports'. We were not discussing impedance mismatch but mode conversion from differential to common (leading potentially to emissions from the cable) or vice versa (leading to a lack of immunity). The functioning of balanced circuits in not radiating the signal and rejecting common-mode disturbances depends on the impedances at each end of the cable, from each conductor to a common reference point, being closely equal. Any voltage between the common reference points is then the input to a balanced bridge, and none of that voltage appears between the signal conductors. And vice versa, of course. While transformers CAN be made with excellent symmetry and very closely equ! al impe dances to the common point, they are not always so designed, and it would be appropriate for the system standard to specify the permitted unbalance, in one of the many ways that can be done. I think this is what the original enquirer is asking about. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk 2006 is YMMVI- Your mileage may vary immensely. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
