TReX DCM min motor speed

Dear all,
I use TReX DMC with mbed in serial mode.
The problem is, that motors start to turn around speed value 20 (out of 127), which is too fast already.
I use 7,4V 2S LiPo battery and Pololu gear motors(
Are there any limits on minimum speed?

Thank you in advance,

Hello, Agris.

The motor might not be moving at commands lower than 20 due to the friction in the motor. Which 25D motor are you using? What speed are you trying to get the motor to turn at? If you are using a lower gear ratio gearmotor, you might consider using one of the higher gear ratio motors to get lower speeds.

You could also try adjusting the TReX’s PWM prescaler parameter. Using a larger prescaler (which corresponds to a lower frequency and longer continuous on time per period) might help the motor start spinning at lower target duty cycles since it allows the motor more time to get moving. You can find more information about the TReX configuration parameters in the “TReX configuration parameter documentation” which can be found under the Resources tab on the TReX’s product page.

- Grant

Thank you Grant,

indeed the gear ratio os rather high. So, It might be the cause. I tried to change the prescler but it did not help.
I’ll try to change the motors and then see if it helps.