Selectively disabling motion axes for Synch CLX

[robertmee]

I have an application that's in initial development. Two sets of 5700 racks, 4 axes each, separate power supplies, separate cabinets The two sets of 4 axes normally operate as one, but the customer has requested if it's possible to physically power one rack down at the cabinet mains and have the other rack continue to operate.

Because of the single motion group limitation, the group won't sync with the powered off axes in the motion group. I know I could ungroup the 4 unused axes, inhibit the modules and get it to run, but is there anyway to do that on the fly, or any architectural tricks to accomplish this feat. I'm suggesting they can STO the unused axes, or even kill the 3phase but the racks need the control power always for comms/,sync.

 

[Ken Roach]

I think your suggestion is the best approach: yellow wires and an "external power" sticker to keep the logic section powered up.

RA might have planned to have multiple motion groups at one time, but they never developed that. I have never seen ungrouping done programmatically.

And putting two separate ControlLogix into a chassis and doing produced/consumed axes is probably overkill.

Sanity check: you still need a SynchLink module to produce/consume axes between 1756 ControlLogix chassis and can't do it over CIP Motion or between CompactLogix, right ?

 

[Lynx777]

I've had mixed results using an SSV instruction setting the "InhibitAxis" attribute to 1.

I say the results were mixed because it did not seem to work as expected every time it was used. In our case we were trying to disable an axis that had a mechanical problem while the rest of the machine stayed in use. All the servos were in the same rack and the servo we were trying to disable happened to be the main power module. I suspect that this was the source of our problem.
Once the mechanical issues were fixed we never tried to use it again.