Centroid Community CNC Support Forum

We had a discussion yesterday in the shop for which I could find no answers in the manuals.

How fast, in i/s/s can the AIODC accelerate and decelerate (properly, on healthy hardware)?

Off-hand, I don't remember which servos we bought, but it was for an R2E4 conversion, they are your servos and power supply, and we left all the acceleration parameters alone.

Thanks,
Lloyd

Lloyd,

Accel is determined entirely on the motor, mechanical load and inertial characteristics of the machine and is not limited by the ALLIN1DC.

For a knee mill such as the yours, you should probably set the accels to ~.300 -Though autotune would probably calculate that the motor CAN accel as fast as .05 or so, I think you'll find it's too abrupt for the machine itself as the machine/mechanicals just aren't rigid enough to handle it.

Ok, that answers a 'config' question.

We let the control auto-tune itself, and we have seen no problems with overshoots or any adverse noises. One of the guys brought the question up during lunch, and I couldn't answer. It's obviously not critical to our use of the machine, but it would be nice to understand how it works, and what the values mean.

In the docs, I can only find how the set the values. How do the configuration numbers correspond to inches/sec/sec acceleration or deceleration rates?
I may presume too much, but it feels to me like a value plugged in there should equate to a specific rate-of-change. Yes? No?


Thanks,

LLoyd

Lloyd,

Our acceleration parameter is not expressed as a rate of acceleration. It is simplified to represent the time it takes for a motor/axis to reach it's maximum velocity. For example, if accel is set to .5, the control will accelerate that axis to max rate in 500 milliseconds.

Thanks, Scott. That explains how it works, and what the ramp will look like. I can do the arithmetic myself <G>.

Lloyd