S4C Controller Fault ?

[Toca1165]

Hi,
I have a fault with an S4C linked to a IRB 1400. When activating the enable device from the teach pendant, K1 and K2 motor contactors are energized. However as soon as the joystick is moved K3 brake contactor is energised and K1 and K2 drop out. Releasing  the enable pad has no effect on K3 and it continues to be energised, the only way to de energise K3 is to perform a warm start. I have swapped the pendant and still encounter the same fault. The schematics show K1, K2 and K3 are activated via Panel Unit A81, the LEDs are all lit before and during activation of the enable device. When the joystick is moved they continue to stay lit with the exception of EN which immediately goes out. If I pull plug X8 on unit A81 then K3 will drop out, but as soon as it is replaced K3 will once again be re energised. Would it be worth swapping Unit A81 ?
Any help regarding this fault would be greatly appreciated.

[ABB robter]

Yes swapping the safety board would be a good idea. Are you getting a fault messages? you could have a bad drive unit which will cause an error then drop the enable.

[Toca1165]

Thanks for the reply,
I have now swapped the suspect safety card (A81) into another controller and all worked fine, so I assume can be ruled out. Now for something completely baffling (to me anyway). You asked if any alarms appeared on the screen, the following is what appears the moment the joystick is moved.

INTERNAL
Unexpected Error.
An unexpected error has occurred.
Report this error with the following code and describe the circumstances.

Tsksup.c 157 exception: task servots vect 11 accaddr = 0X6FF86E; pc = 0X3A9970; sr = 0

I hope this helps, it means absolutely nothing to me and I can find no reference to it in any of the manuals. I will leave this in your capable hands. Thanks again.

[luetin]

I would reinstall the system and see if the unexpected error persists.

[ABB robter]

These type of errors are CPU related because you are having trouble with the drives I would suspect the axis computer but before you swap it take all the drives out and put them in another controller it will be a 50/50 chance that one of the drives are shorted. After this you could reload software but I would swap the axis computer and reload both controllers. By swapping the computers you are also re-setting the board which may fix the problem also. Good luck