CIP motion torque/Position modes

[JasonWade]

Hi

I have a 1769-L27ERM with Kinetix 5500 and CIP motion. The application is a centre driven rewinder.

I want to turn a shaft through a fixed number of turns (at fixed speed) to engage the material, then switch to a torque limit, with maximum speed applied. Torque will then be gradually increased as diameter does. When the material is cut I want to go back to position mode and finish the winding, then come to rest at a known shaft angle.

My difficulty is that it looks like the axis can only be switched between these modes by a download. I can see that I can change the max/min torque (in position mode) and it takes effect immediately, but then the axis ultimately trips on speed error if torque limit is reached before speed is achieved.

Can anybody point me towards a solution? Thanks!

 

[MichaelG]

ok

you are almost there -
yes change the max torque positive using a GSV for torque control
Either Disable the Speed error (and position error) when torque control is active
OR use a MAM command that is targeting a position ahead of your current location and continuously update that position target using MAM with "merge" enabled

What you are trying to do is maintain the "Axis commanded position" far enough ahead of the actual position so the torque control can perform but not far enough to trip all of the errors (position error, speed error etc)

Gotcha's include how the drive is tuned (Position integral gains especially (If you have to you can change the gains on the fly as you exit and enter torque override control))
The drive not following the motion profile when exiting torque control

 

[JasonWade]

ok

you are almost there -
yes change the max torque positive using a GSV for torque control
Either Disable the Speed error (and position error) when torque control is active

Hi MichaelG thanks for the reply

I had thought about this way but couldn't find a way to turn off the error detection (or even raise the threshold).

Also I had selected the torque limit parameters for cyclic writing, rather than using GSV/SSV. Is there a good reason to use SSV instead?

 

[MichaelG]

oops my bad - SSV is the way that I changed max torque on a SERCOS system
the method that you are using is better - cyclic writing

Parameters I think that you are looking for
PositionErrorFaultAction - change from disable drive to "do nothing"
PositionErrorTolerance - Threshold

The threshold is set by the system during an autotune