Temporarily Disable Signal to Servo Amp

I was wondering how to temporarily disable the analog output of the pid for the z axis? During a tool change I believe I'm making the amp overcurrent fault when the drawbar is pushed down. It moves the z axis about 0.05" down.

I would like to disable the analog out for the z axis, do the tool change, then re-enable it.

If it was at a position of say 0.3" before I disabled it, and it got pushed down to 0.25", when re-enabled could it just move back to the original position of 0.3"?

Thanks,
Hunter

I see the pid component has a pin:

pid.N.enable bit in

When true, enables the PID calculations. When false, output is zero, and all internal integrators, etc, are reset.

Maybe I could wire up to this in classic ladder?

-Hunter

Cool, well just correct me if anything I say is nonsensical. I'm a noob

The way my tool change works now is I have in my *.ini file
[EMCIO]
EMCIO = io
CYCLE_TIME = 0.100
TOOL_TABLE = tool.tbl
TOOL_CHANGE_QUILL_UP = 1
TOOL_CHANGE_POSITION = 0 0 0.300

So when I get an M6T1 command the z-axis moves up to 0.300". Then there is a button on the machine I push wired up to classic logic. Q2 is the z-axis lock bar, Q1 lowers the pin to the drawbar, and Q0 extends the pin that releases the drawbar/tool.

I was thinking I would could just wire Q1 to pid.N.enable bit in as well so that while the drawbar is being pushed down the pid for the z axis is disabled as well.

-Hunter

 

Maybe, instead of disabling the PID it might be better to use one or more mux components to soften the PID's settings so that it doesn't push back so hard as to overload the servo. Simply turning off/on the PID will likely cause it to correct the error with a harsh bang movement when it is enabled. Especially if the error is significant. Also you may have problems with following error alarms and might need to figure out a way to subvert them or set them loose enough to not interfere.

Awesome! Now I just need to figure out the details. I have a vague notion of how to wire these things up in HAL. Off to read some tutorials!I included an oscilloscope display during a tool change that didn't fault the amp. The pid is definitely fighting that drawbar pushing down with 2klbs of force!

Yeah, you are exactly right. Right now I don't have any sensor to indicate that the lock plate is in position, I just fire the air solenoid and assume it is. There is a switch I could wire up that is activated when the plate locks.

Here is a video of the lockbar working, and me accidentally dropping my edge finder because I was videoing and not paying attention

photos.app.goo.gl/AH9BLkDeBQpQepMd8

-Hunter