[maint]

Have a Y-Axis DAC oveflow fault on a Bridgeport mill. The fault occurred in the middle of a cutting program. Shutdown the machine. Fault did not clear after restart. Swapped axes drive motors between the X and Y. The fault remained with the Y-Axis. Replaced the Y-Axis power amplifier. The fault still exists. The red and green led's are on for the amplifier. On the BMDC board, D1 led (red) is on D2 led (red) is off and D3 led (green) is flashing. Have minimal documentation at best. Any help would be greatly appreciated!!

Thanks in advance,

Mark

[machintek]

DAC overflow means the control commanded a move but did not see a move.
Could be a bad motor if the axis does not move or a bad encoder if the motor moves but it hits the end of travel. The encoder can be counting but may still be missing the marker pulse for homing.
Swap the X and Y motors and see if it follows the motor.

George

[NC Cams]

If you already swapped the motors and problem still exists, check the cables via a full length continuity check - these do a lot of flexing and consequently do not have an infinite life.

EDIT

From another MACHINTEK post which could help in troubleshooting the encoder circuit on this same control system:

"....If you can get to DOS and go to PFM.exe you can turn the ball screw and see if it is counting. This means the encoder is good. If not you may need to see if it is a bad encoder..."

This test could also check the cabling continuity as well....

END EDIT.



IF the encoders are good and the signal is not getting back to the BMDC, DAC overflow error.

Reason: "....the control commanded a move but did not see a move..."

Clarkson can service the encoders if they go flakey.

It may be necessary to trace the circuit all the way from the MIL connector on the servo to the ribbon cable at the BMDC or at least back to the AXISBOB card.

Worst case could/would be a bad circuit on the BMDC. EMI bench tests them but do the circuit tracing/testing FIRST and save the EMI trip as a last resort. EMI bench testing has gotten pricey of late and service to the BMDC is even more pricey.