[PSES] Conducted emissions AMN/AAN layout

[Andrew Perry]

My friends,

I am preparing to drill new threaded holes in our chamber floor, where we
will perform our CISPR32 (2012) conducted emissions tests.  Looking at
Table D.1 and figure D.2, I am trying to figure out where to place our two
AMNs and single AAN to meet all of the distance and length requirements.

Our setups will look very much like figure D.2, but shape and number of AE
will vary (naturally).  What boggles my mind is how to have fixed positions
for the AMNs and AAN (I don't want to turn my chamber floor into Swiss
cheese), and avoid having to rearrange the EUT on the test table when
switching from AC port measurement to let's say, network port measurement.
Figure D.2 seems to suggest that its layout permits exactly what I'm
looking for.  However, reading the note of the figure (no longer a note in
version 2015, by the way) and looking at the distance requirements in table
D.1, I don't understand how figure D.2 permits EUTs to become AEs, without
rearrangement.

For example, let's say you are measuring the middle EUT using the AAN, then
how can the PSU at the left be >= 0.8m from the active AAN?  The note says
that if the device is AE, then it shall be at a >= 0.8 m distance.  So this
PSU now being AE, shouldn't it be at more than 0.8 m from the AAN?  Is the
figure misleading in indicating that each device can be EUT or AE at its
current position?  Keep in mind that Table D.1 also states that all cables
must be kept at 0.4 m from the vertical plane.  CISPR22 had figures that
showed AMNs all over the place, even bonded to the vertical plane.  CISPR32
now shows all AMN/AAN at the 40 cm line.  D.2.2 text still allows AMN/AAN
to be bonded to the vertical plane, but then how do you maintain the 40 cm
distance for the cables if their endpoint is essentially at a few
centimeters from the plane?

Another question is about this "new" insulation pad underneath the table.
There is a maximum thickness of 0.15m specified for this insulation, but no
minimum.  Are the cable outer sleeves enough?  Is a coat of enamel paint on
a metal turntable enough?  I understand that bare wires shouldn't make
contact with ground if they're not supposed to, but is an insulation pad
really necessary when cables are not bare?

Please let me know what your thoughts are, there must be something I'm not
seeing here.

AP

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Re: [PSES] Conducted emissions AMN/AAN layout

[John Woodgate]

I'm afraid that this is what happens when people (mostly in National 
Committees) accept circulated documents 'because the WG members are 
bound to have done a good job', without actually assuming the opposite 
and go looking for problems. It's all to easy to do.


I /hope I'm wrong in this case/ and someone on CISPR/I WG1 will soon 
explain all, but is certainly seems that, even if the standard is in 
fact totally correct and practicable, it needs clarification.


You say CISPR 32:2012, but the current edition is 2015: 
https://webstore.iec.ch/searchform&q=CISPR%2032 There were a lot of 
proposals for change when the 2012 edition was published.



Best wishes
John Woodgate OOO-Own Opinions Only
J M Woodgate and Associates www.woodjohn.uk
Rayleigh, Essex UK

On 2019-08-09 20:17, Andrew Perry wrote:

My friends,

I am preparing to drill new threaded holes in our chamber floor, where 
we will perform our CISPR32 (2012) conducted emissions tests.  Looking 
at Table D.1 and figure D.2, I am trying to figure out where to place 
our two AMNs and single AAN to meet all of the distance and length 
requirements.


Our setups will look very much like figure D.2, but shape and number 
of AE will vary (naturally).  What boggles my mind is how to have 
fixed positions for the AMNs and AAN (I don't want to turn my chamber 
floor into Swiss cheese), and avoid having to rearrange the EUT on the 
test table when switching from AC port measurement to let's say, 
network port measurement. Figure D.2 seems to suggest that its layout 
permits exactly what I'm looking for.  However, reading the note of 
the figure (no longer a note in version 2015, by the way) and looking 
at the distance requirements in table D.1, I don't understand how 
figure D.2 permits EUTs to become AEs, without rearrangement.


For example, let's say you are measuring the middle EUT using the AAN, 
then how can the PSU at the left be >= 0.8m from the active AAN?  The 
note says that if the device is AE, then it shall be at a >= 0.8 m 
distance.  So this PSU now being AE, shouldn't it be at more than 0.8 
m from the AAN?  Is the figure misleading in indicating that each 
device can be EUT or AE at its current position?  Keep in mind that 
Table D.1 also states that all cables must be kept at 0.4 m from the 
vertical plane.  CISPR22 had figures that showed AMNs all over the 
place, even bonded to the vertical plane.  CISPR32 now shows all 
AMN/AAN at the 40 cm line.  D.2.2 text still allows AMN/AAN to be 
bonded to the vertical plane, but then how do you maintain the 40 cm 
distance for the cables if their endpoint is essentially at a few 
centimeters from the plane?


Another question is about this "new" insulation pad underneath the 
table.  There is a maximum thickness of 0.15m specified for this 
insulation, but no minimum.  Are the cable outer sleeves enough?  Is a 
coat of enamel paint on a metal turntable enough?  I understand that 
bare wires shouldn't make contact with ground if they're not supposed 
to, but is an insulation pad really necessary when cables are not bare?


Please let me know what your thoughts are, there must be something I'm 
not seeing here.


AP
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Re: [PSES] Conducted emissions AMN/AAN layout

[Gert Gremmen]

Drilling holes in  (new) chamber is like drilling holes in your new cars 
roof for an antenna. I can imagine your hesitation. However there is (as 
long as the holes are not to big and correctly made) nothing against it. 
If it allows you to reliably position your AMN devices you  need, a 
swiss cheese will be the best solution.


Regarding the standards... standards are written by guys like you and 
me. Experts in the WG and national committees are not paid for their 
knowledge (which actually is one of the finest on the planet !) , and 
many of them will confirm that they (or their employer) actually need to 
pay to transfer their expertise to IEC. Many members will lack 
motivation (or are not allowed ) to really spend time in correcting, 
drafting and searching for problems in standards texts. Participating in 
standards work is a kind of charity, but for those who are nominated to 
defend their employers interests. So small errors are easily overlooked, 
and it seems that you found a few of them.


Please do not worry and find your own (defendable) solutions, experiment 
and verify if measurement differences occur. There will be. EMC testing 
is not an exact science and standards are should be read as a generic 
guideline. No-one will notice the differences in set-up and no-one will 
challenge them as their own experience will be similar. If your are to 
be audited, referring to the open issues in the standard might help.


Cable lay-out is the most difficult part of emission testing, and small 
difference will make sometimes 10's of dB of differences. Where the 
equipment set up and the room calibration will give you a measurement 
uncertainty (MU) of about 5 dB (if all done right) the EUT setup will 
easily add 15-20 dB to that.


Oh and if you are interested into a better test set-up than CISPR32 
(former 22), look into the CISPR 16 series,especially the chapters om 
measurement volumes.



Gert Gremmen


On 9-8-2019 21:17, Andrew Perry wrote:

My friends,

I am preparing to drill new threaded holes in our chamber floor, where 
we will perform our CISPR32 (2012) conducted emissions tests.  Looking 
at Table D.1 and figure D.2, I am trying to figure out where to place 
our two AMNs and single AAN to meet all of the distance and length 
requirements.


Our setups will look very much like figure D.2, but shape and number 
of AE will vary (naturally).  What boggles my mind is how to have 
fixed positions for the AMNs and AAN (I don't want to turn my chamber 
floor into Swiss cheese), and avoid having to rearrange the EUT on the 
test table when switching from AC port measurement to let's say, 
network port measurement. Figure D.2 seems to suggest that its layout 
permits exactly what I'm looking for.  However, reading the note of 
the figure (no longer a note in version 2015, by the way) and looking 
at the distance requirements in table D.1, I don't understand how 
figure D.2 permits EUTs to become AEs, without rearrangement.


For example, let's say you are measuring the middle EUT using the AAN, 
then how can the PSU at the left be >= 0.8m from the active AAN?  The 
note says that if the device is AE, then it shall be at a >= 0.8 m 
distance.  So this PSU now being AE, shouldn't it be at more than 0.8 
m from the AAN?  Is the figure misleading in indicating that each 
device can be EUT or AE at its current position?  Keep in mind that 
Table D.1 also states that all cables must be kept at 0.4 m from the 
vertical plane.  CISPR22 had figures that showed AMNs all over the 
place, even bonded to the vertical plane.  CISPR32 now shows all 
AMN/AAN at the 40 cm line.  D.2.2 text still allows AMN/AAN to be 
bonded to the vertical plane, but then how do you maintain the 40 cm 
distance for the cables if their endpoint is essentially at a few 
centimeters from the plane?


Another question is about this "new" insulation pad underneath the 
table.  There is a maximum thickness of 0.15m specified for this 
insulation, but no minimum.  Are the cable outer sleeves enough?  Is a 
coat of enamel paint on a metal turntable enough?  I understand that 
bare wires shouldn't make contact with ground if they're not supposed 
to, but is an insulation pad really necessary when cables are not bare?


Please let me know what your thoughts are, there must be something I'm 
not seeing here.


AP
-


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emc-pstc discussion list. To post a message to the list, send your 
e-mail to mailto:emc-p...@ieee.org>>


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site at http://product-compliance.oc.ieee.org/ can be used for 
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Re: [PSES] Conducted emissions AMN/AAN layout

[John Woodgate]

I endorse paragraph 2 below. We in GB are lucky that participation in 
standards work in BSI is free. (But it doesn't stop us complaining about 
the cost of BSI standards - a doozy I found yesterday is £200 for six 
pages, of which three are the actual text.)


Standards work is to a significant extent supported by people who, for 
whatever reason, have more than normal time to devote to it. Quite a 
large proportion are formally retired, and for them, continued 
participation is not only 'making a difference' but also essential 
intellectual exercise.


Makers of AMNs and the like might address this issue by devising other 
ways of attaching the boxes to the ground plane without using holes.  
For example, if there is a sheet of steel under the ground plane. 
magnets on the boxes would work.


Best wishes
John Woodgate OOO-Own Opinions Only
J M Woodgate and Associates www.woodjohn.uk
Rayleigh, Essex UK

On 2019-08-10 10:37, Gert Gremmen wrote:


Drilling holes in  (new) chamber is like drilling holes in your new 
cars roof for an antenna. I can imagine your hesitation. However there 
is (as long as the holes are not to big and correctly made) nothing 
against it. If it allows you to reliably position your AMN devices 
you  need, a swiss cheese will be the best solution.


Regarding the standards... standards are written by guys like you and 
me. Experts in the WG and national committees are not paid for their 
knowledge (which actually is one of the finest on the planet !) , and 
many of them will confirm that they (or their employer) actually need 
to pay to transfer their expertise to IEC. Many members will lack 
motivation (or are not allowed ) to really spend time in correcting, 
drafting and searching for problems in standards texts. Participating 
in standards work is a kind of charity, but for those who are 
nominated to defend their employers interests. So small errors are 
easily overlooked, and it seems that you found a few of them.


Please do not worry and find your own (defendable) solutions, 
experiment and verify if measurement differences occur. There will be. 
EMC testing is not an exact science and standards are should be read 
as a generic guideline. No-one will notice the differences in set-up 
and no-one will challenge them as their own experience will be 
similar. If your are to be audited, referring to the open issues in 
the standard might help.


Cable lay-out is the most difficult part of emission testing, and 
small difference will make sometimes 10's of dB of differences. Where 
the equipment set up and the room calibration will give you a 
measurement uncertainty (MU) of about 5 dB (if all done right) the EUT 
setup will easily add 15-20 dB to that.


Oh and if you are interested into a better test set-up than CISPR32 
(former 22), look into the CISPR 16 series,especially the chapters om 
measurement volumes.



Gert Gremmen




-

This message is from the IEEE Product Safety Engineering Society emc-pstc discussion 
list. To post a message to the list, send your e-mail to 

All emc-pstc postings are archived and searchable on the web at:
http://www.ieee-pses.org/emc-pstc.html

Attachments are not permitted but the IEEE PSES Online Communities site at 
http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used 
formats), large files, etc.

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Re: [PSES] Conducted emissions AMN/AAN layout

[Ken Javor]

I have only peripherally been aware of this thread, but reading these last
two posts makes me wonder why you don¹t have some sheet metal you can punch
to your heart¹s content, but the sheet metal always connects to the floor
beneath it the exact same away. Same concept as a bulkhead plate that can be
punched out uniquely for each individual test set of connectors, but the
bulkhead plate connection to the chamber is the same set of holes and
fasteners.

Ken Javor
Phone: (256) 650-5261



From: John Woodgate 
Reply-To: John Woodgate 
Date: Sat, 10 Aug 2019 12:18:51 +0100
To: 
Subject: Re: [PSES] Conducted emissions AMN/AAN layout

   

I endorse paragraph 2 below. We in GB are lucky that participation in
standards work in BSI is free. (But it doesn't stop us complaining about the
cost of BSI standards - a doozy I found yesterday is £200 for six pages, of
which three are the actual text.)
 

Standards work is to a significant extent supported by people who, for
whatever reason, have more than normal time to devote to it. Quite a large
proportion are formally retired, and for them, continued participation is
not only 'making a difference' but also essential intellectual exercise.
 

Makers of AMNs and the like might address this issue by devising other ways
of attaching the boxes to the ground plane without using holes.  For
example, if there is a sheet of steel under the ground plane. magnets on the
boxes would work.
 
 
Best wishes
John Woodgate OOO-Own Opinions Only
J M Woodgate and Associates www.woodjohn.uk <http://www.woodjohn.uk>
Rayleigh, Essex UK
 
On 2019-08-10 10:37, Gert Gremmen wrote:
 
 
>   
> 
> Drilling holes in  (new) chamber is like drilling holes in your new cars roof
> for an antenna. I can imagine your hesitation. However there is (as long as
> the holes are not to big and correctly made) nothing against it. If it allows
> you to reliably position your AMN devices you  need, a swiss cheese will be
> the best solution.
>  
> 
> Regarding the standards... standards are written by guys like you and me.
> Experts in the WG and national committees are not paid for their knowledge
> (which actually is one of the finest on the planet !) , and many of them will
> confirm that they (or their employer) actually need to pay to transfer their
> expertise to IEC. Many members will lack motivation (or are not allowed ) to
> really spend time in correcting, drafting and searching for problems in
> standards texts. Participating in standards work is a kind of charity, but for
> those who are nominated to defend their employers interests. So small errors
> are easily overlooked, and it seems that you found a few of them.
>  
> 
> Please do not worry and find your own (defendable) solutions, experiment and
> verify if measurement differences occur. There will be. EMC testing is not an
> exact science and standards are should be read as a generic guideline. No-one
> will notice the differences in set-up and no-one will challenge them as their
> own experience will be similar. If your are to be audited, referring to the
> open issues in the standard might help.
>  
>  
> 
> Cable lay-out is the most difficult part of emission testing, and small
> difference will make sometimes 10's of dB of differences. Where the equipment
> set up and the room calibration will give you a measurement uncertainty (MU)
> of about 5 dB (if all done right) the EUT setup will easily add 15-20 dB to
> that. 
>  
>  
> 
> Oh and if you are interested into a better test set-up than CISPR32 (former
> 22), look into the CISPR 16 series,especially the chapters om measurement
> volumes.
>  
>  
> 
> 
>  
>  
> 
> Gert Gremmen
>  
>  
>  
 -


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discussion list. To post a message to the list, send your e-mail to


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Scott Douglas 
Mike Cantwell 

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Jim Bacher  
David Heald 



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Re: [PSES] Conducted emissions AMN/AAN layout

[Andrew Perry]

I'd like to thank all who chimed in with their thoughts.  And yes, I am
well aware of how standards get put together and appreciate the hard work
of those who give them life.  In no way I wanted to criticize their work, I
was just seeking confirmation that I'm not (that) crazy.

I particularly liked the suggestion of using an intermediate plate, into
which I could drill as many holes as I want.  I will explore that idea for
sure.

AP

On Sat, Aug 10, 2019 at 7:19 AM John Woodgate  wrote:

> I endorse paragraph 2 below. We in GB are lucky that participation in
> standards work in BSI is free. (But it doesn't stop us complaining about
> the cost of BSI standards - a doozy I found yesterday is £200 for six
> pages, of which three are the actual text.)
>
> Standards work is to a significant extent supported by people who, for
> whatever reason, have more than normal time to devote to it. Quite a large
> proportion are formally retired, and for them, continued participation is
> not only 'making a difference' but also essential intellectual exercise.
>
> Makers of AMNs and the like might address this issue by devising other
> ways of attaching the boxes to the ground plane without using holes.  For
> example, if there is a sheet of steel under the ground plane. magnets on
> the boxes would work.
>
> Best wishes
> John Woodgate OOO-Own Opinions Only
> J M Woodgate and Associates www.woodjohn.uk
> Rayleigh, Essex UK
>
> On 2019-08-10 10:37, Gert Gremmen wrote:
>
> Drilling holes in  (new) chamber is like drilling holes in your new cars
> roof for an antenna. I can imagine your hesitation. However there is (as
> long as the holes are not to big and correctly made) nothing against it. If
> it allows you to reliably position your AMN devices you  need, a swiss
> cheese will be the best solution.
>
> Regarding the standards... standards are written by guys like you and me.
> Experts in the WG and national committees are not paid for their knowledge
> (which actually is one of the finest on the planet !) , and many of them
> will confirm that they (or their employer) actually need to pay to transfer
> their expertise to IEC. Many members will lack motivation (or are not
> allowed ) to really spend time in correcting, drafting and searching for
> problems in standards texts. Participating in standards work is a kind of
> charity, but for those who are nominated to defend their employers
> interests. So small errors are easily overlooked, and it seems that you
> found a few of them.
>
> Please do not worry and find your own (defendable) solutions, experiment
> and verify if measurement differences occur. There will be. EMC testing is
> not an exact science and standards are should be read as a generic
> guideline. No-one will notice the differences in set-up and no-one will
> challenge them as their own experience will be similar. If your are to be
> audited, referring to the open issues in the standard might help.
>
> Cable lay-out is the most difficult part of emission testing, and small
> difference will make sometimes 10's of dB of differences. Where the
> equipment set up and the room calibration will give you a measurement
> uncertainty (MU) of about 5 dB (if all done right) the EUT setup will
> easily add 15-20 dB to that.
>
> Oh and if you are interested into a better test set-up than CISPR32
> (former 22), look into the CISPR 16 series,especially the chapters om
> measurement volumes.
>
>
> Gert Gremmen
>
> -
> 
>
> This message is from the IEEE Product Safety Engineering Society emc-pstc
> discussion list. To post a message to the list, send your e-mail to <
> emc-p...@ieee.org>
>
> All emc-pstc postings are archived and searchable on the web at:
> http://www.ieee-pses.org/emc-pstc.html
>
> Attachments are not permitted but the IEEE PSES Online Communities site at
> http://product-compliance.oc.ieee.org/ can be used for graphics (in
> well-used formats), large files, etc.
>
> Website: http://www.ieee-pses.org/
> Instructions: http://www.ieee-pses.org/list.html (including how to
> unsubscribe) 
> List rules: http://www.ieee-pses.org/listrules.html
>
> For help, send mail to the list administrators:
> Scott Douglas 
> Mike Cantwell 
>
> For policy questions, send mail to:
> Jim Bacher 
> David Heald 
>

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Website:  http://www.ieee-pses.org/
Instruct