[pquerro]

I have a Sabre 1500 with an A2100 control. BDS4 Servo Drives. The machine powers up just fine and I am able to align the machine just fine. I can move the X and Z axes fine. The Y axis will move out approximately 15 inches and the machine shuts down with a servo drive enable signal lost. I can clear the alarm, power the machine back up and move the axis back to the home switch. This seems to happen in about the same position every time. Any ideas on what would be causing this??

[mallardfizz]

hello
i think you have a broken 'X' axis cable. the x cables routed under the saddle and thru a drag chain under the column. this drag chain has a bend in it which opens and closes as the 'y' axis moves backwards and forwards. this flexing causes the cables to fail. if it is a broken power cable then start the machine and if you can re-create the problem by moving the 'y' axis backwards and forwards BEFORE you align the machine you could then remove the 'x' axis motor cable from the bottom of the drive and try moving the 'y' axis backwards and forwards and the fault should not occur. a broken feedback cable is more difficult to diagnose. if you go to the back of the machine and look in the area of the 'y' axis motor you will see the cables coming from the drag chain under the column. is one of the cables an orange color? or are they all grey- sorry gray. the original cables were gray and these become brittle and break with time. they were replaced with an orange coloured cable which is much more flexible and not prone for failing. i use a test cable which i run round the outside of the machine to prove out cables. broken power cables are a common enough occurance and probably the worst job to do on these machines.
best of luck
regards
mallardfizz

[pquerro]

Thanks for the info!! The machine does fault out if I have NOT Aligned it and move the Y axis past the "point" . The cables are indeed gray. The power cable comes in to screw terminals on the drive. So what you are saying is to power the machine up, remove the wires from these terminals on the X drive, and move the Y axis BEFORE aligning?
Thanks so much for the help!
If it is indeed cables - where is a good source for replacements?

[mallardfizz]

hello
for safety i would remove the 3 wires on the bottom of the drive when the machine is turned OFF. Remove the wires and start the machine. if the fault goes away it is the power cable if the fault remains it is the feedback cable.
regards
mallardfizz

[pquerro]

So I took the power wires off the drive, still errors out. So we assume its the feedback cable. I pulled the way covers back and it has heidenhain scales on the x and y axes. Could this be the source of the problem? Since I don't have a new feedback cable to swap out, is it safe to assume I can simply check continuity before and after the error occurs? Thanks Again

[mike_Kilroy]

Mallardfiz is the expert so wait on his response of course too, but...... something wrong with this picture I think...... If the linear scale is the problem then you do NOT get a servo fault - you get run away or excess error fault on 2100 instead. So I say NO it is not the scale. I think Mallardfiz is trying to get u to identify if it was the motor cable or the motor feedback cable. You have TWO feedbacks on this machine; the scale that goes to 2100 position loop cnc and feedback inside the motor that goes back to the drive (where u r having problem).

BTW, if you get drive fault I believe the red lites on the BDS4 will show u which fault caused it - so which one is on? feedback loss lite says its the feedback or its leads, overcurrent says its the motor or its leads. this is a latched fault that we left on for u to see after a fault to help identify the problem.

Since these are our drives we of course repair them also.

[pquerro]

I don't have a feedback loss light on these drives. I powered it up again and the overspeed led on the x drive came on when it errored out.
thanks

[mike_Kilroy]

we added more red fault lites later in the bds4's life so I was not sure if u had one or not. overspeed is also typical if feedback is lost. at least it is not overcurrent which is more indicative of a motor power cable. Since it happens at certain position, Mallardfiz likely has ur problem pegged to this cable.