Default setting of microstep resolution?

[Victor]

Hi,

I am using the simple example/application in the getting started manual to understand how to program our linear actuator. A hybrid linear actuator 1,8degree step angle = 200 steps per revolution (200 fullsteps per revolution) and linear travel 0,0487mm/step.

The command MVP ABS, 0, 15000 in the application "moves" the motor to position 15000. But when comparing the measured distance with calculated distance I don`t seem to get similar figures (big difference).
So what microstep resolution is used as default by TMCM-110? can that be my issue?

Thanks
Victor

[Andrew]

TMCL uses 64x microstepping by default.
To read the current microstepping rate for a given axis use this command:
GAP 140, 0, 0
This example fetches the paraemter #140 "microstep resolution" for axis 0.

In your case the distance of 15000 in full steps would mean: 730.5mm
At natural for TMCM110 16x microstepping: 45.65625mm
And at the default 64x: 11.4140625mm.

Note that at an unnaturally big microstepping rate for a given module, not every microstep actually produces a motion. Also the motion is slightly irregular even at natural microstepping.

Another cause for wrong position would be missed steps (a stall).
Wrong speed or acceleration might cause a stall. Some stalls are very prompt - just a few steps.
You may no actually notice it until you arrive to destination.

Please read a fundamental discussion about these and other issues here:
http://www.trinamic.com/ttdg/viewtopic.php?t=263