Problem- "master encoder state error" AB ultra100 error message

[ShapeShaver]

I have finished installing Allen Bradley ultra drives and motors on my machine and it is moving fine but the drives keep randomly faulting out and the ultramaster software gives me the error of "Master encoder state error" Which I understand is referring to the step and direction signals that are wired to the same pins that an input encoder A+ and B+ signals would use if it were in Position Follower (Master Encoder) mode which is used when one servo is to be electronically geared/coupled to another by using it's encoder signals to keep them in sync.

I have the drive wired up for step and direction control and set up as Position Follower (Step/Direction). I have followed the connection guide and have the step+ and direction+ wires hooked to their pins. I have the Step- and Direction- wires hooked up to PC ground. This method of hooking up the drive is commented on by Allen Bradley as "External Step/Direction Interface via Single-Ended TTL Line Drivers (not recommended)"

I used this same drive/motor combo years ago on a machine and it worked great. So I am at a loss as to why I would be having this error and I can not find any documentation on what the error means or what causes it within the drive.

I am using CandCNC's UBOBIII break out board and Mach3

Anyone have any experience or knowledge that might help?

Thanks in advance, ShapeShaver

[Larken]

Sounds like your getting random noise on the encoder lines (or comutator lines) that is confusing the state decoder. Is this a Brushless or AC servo ?

[mike_Kilroy]

i agree step/dir line noise. as manual said, non differential input is not recommended.

are the step/dir lines run in a shielded cable with shield tied to ground at at least one end? if not, try that. if it doesnt fix, tie shield at both ends and try it. if that doesnt do it see if u can move this wire away from any motor leads of power leads. if that doesnt work sounds like time to buy a $ 100 single ended to differential line driver and stick at the mach3 location and do it right.