Hi, thanks for your feedback, I have been to similar issue again and there are 3 servo drives on the equipment and it isn't always the same drive which has an instruction issue similar to the one described above. it also isn't always the same rung which gets stuck.
The latest fault was on a MAG (Gear On) instruction, when I got to the machine I could not see any fault codes etc on the drive, however there was an error code when expanding the Tag, ERR 5 which I believe means the servo loop was open. and also a safe torque off alarm was present in the drive status after clearing the log.
if anyone could take a quick look at the word document attached, and has any ideas that would be a big help.
Line 5 fault.docx