velocity and torque readbacks

[JeffB]

I'm using some motors via a Yaskawa ethercat amplifier in position mode.

 

I would like to read the velocity and torque. When I read the velocity by the chart program the values look reasonable but when I log the Motor[0].ActVel in an array the numbers are mostly 0. I also log the position (ActPos) and time (Sys.RunTime) so I can calculate a decent velocity value using (Δp/Δt) but I don't understand why the ActVel doesn't show correctly and why it seemingly does show correctly in the chart (I exported the chart data). Also my calculation has some ripple that I'm not sure is real or is a product the times not being in perfect sync with the position reads.

 

For torque I can see the IqMeas doesn't change; the IqCmd does. But I think I should be reading this from the Ethercat amplifier directly (ECAT[0]…) but not sure what variable to type.

 

Thanks

[Omron Forums Support]

When I read the velocity by the chart program the values look reasonable but when I log the Motor[0].ActVel in an array the numbers are mostly 0.

Are you moving considerably faster than 1 count per servo/ecat cycle?

Are you using Motor 0?

Can you post the plot of ActPos and ActVel for this motor?

 

For torque I can see the IqMeas doesn't change; the IqCmd does. But I think I should be reading this from the Ethercat amplifier directly (ECAT[0]…) but not sure what variable to type.

In position mode PMAC does not know how much torque/current is in the motor. We send the drive a desired position, it sends back an actual position. If you are lucky enough to have an input PDO with actual torque you may have to plot that or add it to the watch window.