The only time we've had issues like that has been due to either a dodgy network cable or an RJ45 plug getting a bit grubby. First thing I usually do is unplug/replug all the plugs a few time to clean up the connections. If it persists then I start looking for bad cables.
Another option is that there is an occasional noisy process causing noise on one of the links. Once or twice (only on non-ethercat machines so far) we've had cables that were in drag chains wearing out, where it showed a problem when at a specific position of the drag chain. You could track down if it's a problem with a link between two particular slaves by checking each slaves Link Lost Counter and CRC Bad Counter values. - Lost Link Counter Register (0x0310:0x0313) - RX Error Counter Register (0x0300:0x0307) This link describes some of the diagnostics: http://www.automation.com/automation-news/article/diagnostics-with-ethercat-part-4 I think you can set the above registers to zero after the fieldbus is up and running, then you can check them if a problem occurs. Haven't actually done it yet myself, so would be interested to see if it helps you. Regards, Graeme. -----Original Message----- From: etherlab-users [mailto:etherlab-users-boun...@etherlab.org] On Behalf Of Henry Bausley Sent: Saturday, 2 July 2016 5:56 a.m. To: etherlab-users@etherlab.org Subject: [etherlab-users] Intermittent Large number of datagrams UNMATCHED We have a etherlab 1.5.2 kernel mode application running in xenomai 2.4.6 on Ubuntu 14.04.1 Desktop that will get on rare occasions a large number of datagrams UNMATCHED. It occurs at random times and relatively rarely but when it occurs it can result in disaster as we are running a large number of servos in torque mode. For example we can run continuously for 5 days 24hours continuously then get a message like something below. [591785.735172] EtherCAT WARNING 0: 616 datagrams UNMATCHED! I am struggling as to where to look. Is this something in our app or a known bug in the stack? Outbound scan for Spam or Virus by Barracuda at Delta Tau _______________________________________________ etherlab-users mailing list etherlab-users@etherlab.org http://lists.etherlab.org/mailman/listinfo/etherlab-users _______________________________________________ etherlab-users mailing list etherlab-users@etherlab.org http://lists.etherlab.org/mailman/listinfo/etherlab-users