Allen Bradley servo controls

Good morning all,
I wasted couple days trying to figure out the setup of a 1756-M02AE servo card to control two axes on a machine. I have a linear axis that I managed to set up to have good positioning, and rotating axes (for the other half of the M02AE) which I seem to be unable to get to move (rotate) properly Sometimes I get it to move couple degrees in any direction, but almost instantly the card faults out. I couldn't use the values set by the auto tuning procedure either. I read the documentation I've found about setting this up, but it didn't make me any smarter . I need to mention that I don't have too much experience with motion control, but setting up the linear axis was fairly easy.
Both axes have DSM-100 Centurion amps and servo motors. The CPU is a ControlLogix5555 rev 16.xx
I would appreciate any help to get me through the setup of the rotating axis.
Thanks guys!

What sort of fault did the card indicate ? The most common would be a following error, but maybe it's a feedback error of some kind.

Have you verified that you are getting a good clean encoder signal on the M02AE's encoder inputs ?

Does the encoder go directly to the M02AE, or does it get buffered through the G&L amplifier first ?

Thanks for the quick reply..
The card gives me a physical drive fault?!?!?! yet I see no error on the amp.
The encoder gets buffered through the G&L first, then sent to the M02AE. I have an identical setup for the linear axis (the other half of the M02AE) that works great. The only difference (physical) between the axes is that one goes back and forth and the other rotates.

just a guess on my part, have you looked at the encoder feedback wiring? if the wiring signals is wrong, would this create the error.

i'm familiar with Boston Millicron cnc machines and bad wiring creates a problem with them.

regards,
james

Do you have the Drive Fault circuit wired between the M02AE and the drive ?

Are the OK or FDBK LEDs turning red when you get this fault ?

The 1756-M02AE doesn't get nearly as much information from the drive as a SERCOS or CIP Motion drive gets. It really just knows the encoder feedback pulses and the state of the DRVFLT circut.

What exact motion instruction are you executing that results in the fault ? Is it just a servo enable (MSO) or are you doing an Axis Move or something else ?

I don't have to use a statement to fault the card...just trying to tune it for "axis properties" window results in red light(s) on the card. The Ok light is green since the card is enabled, the feedback and the drive LEDs go red sometimes together sometimes just one (I couldn't relate the LED to a specific fault condition).
You're right Ken,there is minimal information transfer between the card and the servo amps (other than the encoders)...a status signal from the amp to the card, and an enable signal the other way.
The funny part is that we had this channel working couple days ago...being an axis that just revolves, it was safer to start with it, then go to the one that actually moves the machine. Ever since we've got the linear axis going, the rotating one faults out.

Intermittent faults when you enable the servo position loop suggest a problem with your encoder hookup or signal.

Check out RA Knowledgebase Article # 46847's description of the module LED states to see if they match your module's behavior.

I would focus on the feedback signal: check your wiring integrity physically and your signal integrity with an oscilloscope.

I would also recommend disabling the linear axis entirely (both logically and by powering it off) to see if it's electrically interfering with the feedback on the rotary axis.

Thanks Ken!
I will investigate and post my findings.
Cheers,
Alex

I did some investigation, connected the linear axis to CH0 and the rotating one to CH1 to ensure the M02AE is OK on both channels. Linear axis works the same on CH0 (so, the card is OK). The rotating axis looks like it had a bad connection on the feedback side... ; that's fixed. Now I don't get any more feedback errors on the M02AE.
But as soon as I enable the drives (all green lights on the M02AE), the rotating axis G&L faults out. It is either E23 or E24. The manual says Internal filter protecting the IPM at slow speed has tripped for E23, and Velocity error exceeded the specified limit and time parameters for E24.
I keep playing with the tuning, but so far no good result. The values mentioned in the manual(s) didn't do me any good.

It was something wrong with the G&L...took them(service place) almost three weeks to get it done.