Jrk 21v3 position control of Micro Metal motor with encoder?


I suspect I have journeyed down a blind alley but want to ask on the chance that I want to do is possible.

I would like to uses the Jrk 21v3 controller with a Micro Metal Gearmotor (equipped with shaft mounted encoder) to control the position of the gearmotor output shaft. I expected that I could command the Jrk to a position via a servo pulse on the control input and have the controller monitor the Feedback (pulses from one of the encoder channels) and count the pulses until the target position is reached (countup for forward, down for reverse drive direction). But this approach would also require some type of index or home function to indicate the zero position which does not appear to be a feature of the Jrk.

I am starting to believe the Frequency input cannot be used for counting encoder pulses for position feedback. If this is possible please give me a few tips on getting started. Is the Frequency (digital) feedback useful only for motor speed or is there away to use this input to monitor motor position?

Oh, and you guys rock!


Hello, Shane.

No, the jrk cannot do position control with only tachometer feedback. However, you can configure the jrk to take standard RC servo pulses and command the position of a motor if you use analog voltage feedback. For that, you would have to connect something like a potentiometer to the output shaft of your motor to sense how far it has rotated.

Invenscience actually uses our jrk 21v3 for position control inside their i00600 and i00800 Torxis servos.

By the way, thank you for the compliment!