currently we have one cell that has been causing some issues. for no reason the table begins to rotate either at the operators side or at the welding area.
This cell might run for over 6 months without any issues and for no reason it will flip a table when it shouldn't, this happens once and up to three times with in a few days and then goes away for a a few months.
when the table flips is always after an arc out, shock sensor, collision detect ,weld edit or any other robot stop ( programed or not). S1 has never rotated only S2 and S3 at either side (operator or weld side). when this happens at operators side the safety kicks in and stops it but not after it has move a few degrees, this is our main concern as it might injury an operator. when it flips at the robots well, it rips the torches out of some robots causing major down time.
Servo card, amplifier, IO card and CPU has been replaced without success. when S1 or 2 moves there is no program calling that rotation, i have paged through the programs and there isn't one calling it. once everything gets homed it runs like nothing had happen.
we never lose the position of the table, it doesn't cause a minor/major fault and we clear the fault by pressing reset.
Please let me know any suggestions even if I have already done them, also what you think it might be the problem as it can give me ideas on how to fix it.
thanks in advance.
PS. when I say ROTATE it rotates with full speed and full power and if i don't home and master the entire cell and just click restart it will continue to rotate.