Hi guys

Pncconf doesn't currently have a test for servo control
besides open loop testing. The reason is I need a 
program that will create velocity commands  to
supply the PID control. For steppers the program
steptest.comp does this. I tried it with servos a 
long time ago and it didn't seem to work right, I
was busy with other things and dropped it.
looking at the program (steptest) a couple questions
come to mind.
- steptest has an input pin for max acceleration but its
not used internally. Why?
- the lines:
<snip>
     if(jog_minus) {
        position_cmd = position_fb - 2 * maxvel * fperiod;
    } else if(jog_plus) {
        position_cmd = position_fb + 2 * maxvel * fperiod;
    } else {
        position_cmd = position_fb;
    }
}

I don't understand. How does 2 * maxvelocity * time 
give the next position command if there is no idea if
the motor is at max acceleration?
I would have thought  acceleration * time limited by
maxvelocity would be in there somewhere.
I do realize that the stepgen component its self
limits acceleration and maxvelocity and I'm thinking
this is why the test works anyways.
Am I missing something?

Is there anything off hand that a servo test would need
that steptest doesn't do?
If steptest.comp can't be shoehorned I will build a 
servotest.comp program
I've attached EMC's steptest.comp for convenience
if anyone wants to look at the whole program.  
Thanks
Chris M   
                                          

Attachment: steptest.comp
Description: Binary data

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