[etherlab-users] Missing Vendor ID / Product Code

[Gavin Lambert]

There’s lots of things that can cause that.  Most often, I’ve seen this when packets get lost or corrupted, so the initial discovery datagrams get lost or fail.  Usually bad wiring or shielding is the culprit.

I think it might be possible to get something similar due to an unfortunate timing coincidence – if the devices are being connected “live” then a dodgy plug-in could make the device visible in the initial device count scan, but then disconnected before it finishes the identity discovery, but then reconnected again before it does the next device count scan (so it doesn’t try again).  Replugging the devices (with less unfortunate timing) or restarting the etherlab service should both recover from that case, however.

Or, of course, you might have found a bug. 😊

It's hard to say for sure what actually happened without seeing syslogs and/or reproducing it.

From: Graeme Foot
Sent: Wednesday, 8 August 2018 14:12
To: etherlab-users at etherlab.org
Subject: [etherlab-users] Missing Vendor ID / Product Code

Hi,

I updated my EtherCAT system to use Gavin's patch set (revision 10, 20171108).  It has been running fine on a few machines, but have just had a machine being commissioned where one of the slave modules had a zero Vendor ID and Product Code (and I suspect it failed to read any information from the slave).  Unfortunately it occurred while I was not available so our engineers reverted to the previous version (which detected the module correctly) and shipped the machine, so I have very minimal information and no logs.

The module with the problem was the 17th module, the first EL2612 of 5.  It is directly after an EL9410 power module.  It has an explicit alias set.  The engineers had tried repowering the whole system and replacing the module.

Until I get a machine to test on with the same behaviour I was wondering if anyone else has had problems with slaves not initialising correctly.

Thanks,
Graeme Foot.
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