Electromagnetic compatibility (EMC)

[Jakob Z.]

Dear RevPi team,

the RevPi Core 3 module has been tested by you in accordance with EN61131-2 and 61000-6-x.
Volker mentioned in https://revolution.kunbus.de/forum/view ... ?f=3&t=363 that the PiBridge uses a transmission rate of no more than 1 MBit/s (due to EMI issues above that rate).
I wonder: Have you also tested multiple interconnected devices (e.g. a RevPi Core 3, an AIO and a DIO module) regarding emission and immunity? I see the PiBridge as a rather critical component. Have you gathered experience on that topic that you could share?

Thank you!

[volker]

Hi,
yes, when testing emission / imission we always need to use the combination in order to operate the DIO / AIO / Gateways. So we meet the requirements using EN 61000-6-4 test procedures with complete setups.

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[Jakob Z.]

Hi Volker,

great! Thank you!

[volker]

Jakob,
please also take into account that emission according to industrial standards is less restrictive compared to consumer home products. In home environment the norms try to reduce emission as much as possible whereas consumer produces are much more sensitive to imission. In industrial environment emission is not as important as you have plenty sources for much higher emc emission (switching high currents and inductive loads or welding etc.). Therefore the norms are very restrictive in sensitivity to imission. Imission to the PiBridge had to be taken care of by using a solid protocol with retransmissions in case of emc disturbed signals. Emission is very close to the limits set by the norm.

[lars]

Hi Volker,

we are considering to use a RevPi core for the development of a larger laboratory device mainly as "USB device server". For this laboratory device we will have to be compliant at least to EN 61326 and FCC 47 CDR Part 15. From your experience: do you think this would be possible or should we plan an additional metal casing around the device or special treatment on the power supply to pass the EMC emission tests?

Would it be possible to get access to measurement reports (under CDA if desired) from your EMC measurements in order to be able to evaluate the situation by ourselves?

Best,
Lars

[volker]

Hi Lars,
which are the critical parameters? Is it sensitivity to external radiation level or the emission level?
Shielding works only for low frequencies. If we are talking about > 1GHz then shielding is not sufficient because of the wires and connectors which need to break the Faraday cage.

USB? This is something I would have bigger concerns about. We have constructed our USB ports to the USB compliance. This means the shield has never to be connected to the 5 V VBUS GND. The fact is, that we have realized that 90% of all USB devices directly short cut the shield to the GND. With out actual RevPi Core this does directly shortcut all our protection circuits and results in a high vulnerability of the device. So if you do permanently connect USB devices to RevPi Core please use plugs in between which assure a separation of shield and GND. Wuerth for example sells such adapters with little jumpers to select GND and shield path the way you need it.

If you can specify a little more your EMC needs i can try to send you test reports with relevant results.

[Baarsjes]

Hi,

In the CE DoC's of the industrial plc's I have seen the units are EMC tested following IEC 61131-2:2007.
Could it be possible to specify also the 'zone'. A, B or C?

Could we receive the test reports from the test house?

IEC 61131-2:2007 is already updated to IEC 61131-2:2017.
This update will be in near future the harmonized EMC standard for PLC's.
Already tested to this update?

Are there any installation guidelines how to use the product is an industrial cabinet?

Thanks.

[dirk]

Dear Baarsjes, For which devices do you intent to work? As then we can give you all the issues that are for your interest.
What do you mean by zone A,B,C ? We have tested using the 2007 specs. If the specs have huge differences we'll update them.