Re: [802.3_10SPE] questions on Evaluation of Immunity Aspects in Multidr

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Hi Jay,

I am sending Galin's answer. Please let me know if you have more questions.

Best regards,

Fatma Caliskan

-------------------

Hello Jay,

I acknowledge there are missing pieces of information – the presentation format, unlike detailed technical report,

makes it hard to maintain the focus of bringing your message and still back it up with enough technical facts, yet not distract too much from the main topic/message with too many details…

I guess same applies to your slides – there I’m also missing information about the cable and any common-mode termination information, which is essential for the CM evaluation purpose – can I on my side ask you to clarify those? Thank you in advance!

That’s why we have the chance to follow up on those here!

To your questions:

As you may have already assumed from the setup drawing dimensions - we have started with BCI using substitution method using CW only at 200 mA. As I mentioned our effort is “work in progress” – even now we continue retrieving more data…

We plan to do also closed loop, but as I mentioned in the meeting – all those tests are “device level” only – and are less suitable for testing multi-drop harness, with multiple devices, different length cables, etc.

In such complex system it is e.g. not that obvious where you need to place your monitoring clamp, right?!

We had flat 200 mA over the presented frequency range. The idea was to get the base-line and good foundation for further modeling of the system.

Calibration was conducted as described in ISO11452-4 Chapter 8.3.1.2.2 Calibration/Annex A, using BCI calibration fixture.

There were different grounding configurations tested and presented – in general there are two separate (isolated on the PTC) ground regions per Test Card (as shown on page 5):

one on the measurement side (used for probe attachment/measurement traces and adaptation/Board IDs). This one is always connected to the copper table ground by means of ~1 cm Wire connected to broad copper foil connection run across the 5 cm foam to GND. It was empirically found that the added parasitic components (C,L) of this measurement fixture are insignificant for the frequencies < 100 Mhz.
one on the “PHY”/cable side. This one serves as connection point of the center point of the split termination:

for End-Node / End-Terminated configuration this is the middle point of two 50 Ohm resistors (total of 100 Ohm differential),
for Drop-Node configuration this is the middle point of the two 1 kOhm resistors (total of 2 kOhm differential)

Based on the configuration currently being tested (e.g. Strong CM connection/Weak CM connection) – this ground area/middle point of the split termination is either connected to the copper table by means of separate (to minimize inductive coupling!) ground wire with total length of ~ 6 cm or left floating/not connected.

If it is still unclear – let me know and I can provide that info in graphical format.

Used cable specification are:

For the each cable of the pair: AWG22, stranding 7x30, Irradiated PVC, BLACK/ORANGE, wire overall nominal diameter: 0,050 inch/1.27 mm

For the pair: nominal twist rate 0.55 inch/14 mm

Different cable lengths are currently in evaluation, but the one used for correlation to your use-case has total cable length of 9 meter (one of the loops is actually a bit longer) with 5 cm tap connected at a distance of 3 m from the far-end (other side of BCI clamp) termination node.

Let me know if that answers your questions detailed enough.

Best regards,

Galin Ivanov

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Re: [802.3_10SPE] questions on Evaluation of Immunity Aspects in Multidrop Channels presentation