351 SPC Alarm A-Axis help

Hello all,

Leadwell V30 with 21-M and Troyke DL-10-B

Machine has been throwing 351 SPC Alarm A- Axis Communication on occasion for the last few weeks but now it is generating the alarm very frequently.

It appears that the alarm is related to spindle starting/stopping and usually happens during a tool change or just afterward.
The condition has not yet occurred during a cut but it did happen once when the spindle was warming up with no axis movement.

Manual input of spindle orientation M19 and Spindle on will sometimes trigger the alarm.

I have a short program that rapids and feeds all of the axis about the travels with no spindle movement and this has yet to generate the alarm.

Any troubleshooting procedures will be appreciated.

Thanks,

Dave

generaldisarray,

Thanks for posting the link. I found my fanuc series 21 maintenance manual over the weekend and the diagnosis 202 is showing #6 CRC. The CRC description in my manual says: Replace the Pulse Coder, Feedback Cable or the Servo Control Module

Anyone know of a way to narrow this down?

Thanks,

Dave

Not that I know of, its kind of a parts cannon situation. But you can start at the cheapest part first.
check all the feedback cable connections first. You know what axis and you know it is only the feedback. actually unconnect and reconnect a couple times at every connector.

second, I would try to induce the alarm with ferocious wigglin. of the cable. being a rotary I would guess the problem is in the cable where it flexes.

Even if you cant make it alarm out, still replace the cable. I have used this guy and would use him again >> Machine Tool Cables – Replacement Cables for Your CNC Machine

If the cable does not fix it, try to swap that pulsecoder with a different axis.

If the problem still exist on that axis, try to swap drives if possible. Being a rotary its likely it is a different size. In that case you can send it out for evaluation.

I dont think I have ever messed with a non (i) 18. So before yeeting a pulsecoder off. Make sure you are familiar with how to put it back on.