"master encoder state error" AB ultra100 error message

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

Oops, I just saw that I put this in the Live PLC Q&A forum. Not sure which forum it should be in.

I would be interested in exactly which model of Ultra 100 drive you are using, so I could at least take a look at the exact user manual. These drives were the first A-B branded generation of the venerable Electro-Craft IQ series, but the Ultra 100's have been out of production for quite a while.

You can get a "state error" from the Motor Encoder, the Auxiliary Encoder, or in your case the Master Encoder input when the encoder signal isn't usable by the Ultra controller.

What you can do for help from the Forum is post a diagram of exactly which of the hookup diagrams in the Ultra 100 Installation Manual's Chapter 6 is most similar to your output board -> Ultra100 hookup, and maybe provide some link to the installation instructions for the breakout board.

My approach would be to attach an oscilloscope and see if you can relate the encoder input faults to a particular event or state of your system, whether that's the trigger of a torch or contactor, or a specific power or speed condition.

Thank you for your reply. I have the 1398DDM 009 drives. The link to the BOB instructions is

http://www.candcnc.com/PDF/UBOBIII_Manual-rev1.pdf

As i mentioned, I have pin 15 and pin 17 connected to PC ground because the bob I have only outputs single ended TTL Step and Direction signals.