Problem- G320X faults, while G340 is fine

[motioncontrol]

I have a nearly completed Bridgeport Servo retrofit that I am using Electrocraft E712 motors, with Renco 1024 line encoders. I have an external 5v power supply for the encoders. The X and Y axes have G320X drives. The Z has a G340, just because I had a spare from my other machine. When I perform the encoder test in Mariss's documentation (motor windings not hooked up yet) both LED's light green on the G320X's and I can slowly turn the motor until fault, and the drives self reset. Once I hook up the motor windings on X and Y, with no pulse source present, the G320X's will intermittently fault and recover, just while the the machine is idle. When I try to make moves in EMC2, the table will sometimes move for 3-4 inches before a fault, other times it will bump a very small amount before faulting. The strange thing is that I can plug the X and Y motors/encoders into the Z connectors, which has the G340 on it, and I cannot make the 340 fault no matter what I do. Is the 320 a more "sensitive" drive than a 340 when it comes to external noise, and other disturbances? Are there any obvious things that I might have overlooked, that I should be looking at first to track this down? Thanks.

[sbalder]

Did you ever get a reply on this? We did a Bridgeport R2E3 retrofit with G320's and it was simple and perfect. We did an identical one with 320x's and got exactly the same experience you are describing. Despite their literature stating at the time "The G320X is 100% backwards compatible with the G320 and G340" this really was not the case. After many, many hours of wasted time and looking like an idiot to my customer I wound up completing the retro at my expense by replacing his servos with new steppers and drives. Some time later they came out with a bulletin to use pullup resistors and a capacitor and I was able to get the 320x's out of my trash pile and use them on a much smaller machine. Even in this application they would still fault under moderate loads.

You might want to try the bulletin on Gecko's site. For my money I will steer wide clear of the 320x's and use the 320 or 340 as long as they are available. There are also other good DC drives available beside these and great options to use steppers or AC servo drives.