Only one way speed control using a JrK21V3

I’m trying to configure a Jrk21v3 as one direction speed control, using a potentiometer as input.

The motor turns left until midpoint on potmeter, then reverses direction on the other half.
I’m trying to get 0 RPM when the pot is all the way left, and MAX Rpm when it is all the way Right, in one direction.

How do I configure this ?

Hello, imnama.

You should set the jrk’s Feedback mode to None because you are not using feedback. In this mode, a target value of 2048 will stop the motor, while a target value of 2648 will drive it full speed forward and a target value of 1448 will drive it full speed backwards.

You should set the input mode to Analog because you are using a potentiometer as input. Ideally the potentiometer should be hooked up so that when you turn it, the voltage on the jrk’s RX line varies from 0 to 5 V. It’s good to verify this with a multimeter. As the voltage changes from 0 to 5 V, the jrk’s “Input” variable changes from 0 to 4095.

Then you just need to set the Input Scaling parameters to map the input values (0 - 4095) to the desired target values (1448 - 2648). You want every value below a certain threshold to map to 2048, and values above that threshold to map to 2048-2648. Something like this should work:

          Input     Target
Abs. Max  4095
Max       4095      2648
Neu. Max  500
Neu. Min  0
Min       0         0
Abs. Min  0

You should adjust the “Neutral Max” and “Max” parameters to fit your particular potentiometer and preferences. Making neutral max smaller will decrease the dead zone. Making max smaller will increase the region of potentiometer positions where you get 100% duty cycle.