Novice Velocity PID Instructions?

[nickosinski]

Hello again,

My next question... in playing with the P value and leaving D/I at 0 (zero), I'm able to get 2 motors to traverse the same distance, but one will always run faster than the other - so one always seems to reach the desired distance total sooner/earlier than the other motor.

I obviously want the motors to not only travel the same total distance, but do so at the same rate/speed. What do you think I'm doing wrong?

Thank you again,

Nick.

[Basicmicro Support]

1. Sorry, this thread has gotten long and I didnt remember you are using a very old model.
2. P means proportional. It doesnt regulate speed very well. For true speed control you must use P and I. But the fact there is a big difference in speeds between the two motors indicates the P settings for the motor is not correct. Note the settings will not necessarily be the same for both motors. Even if they are exactly the same mode and have the same load. Usually its close enough but sometimes its not.

[nickosinski]

Thank you so much!!!

I think that is one of the fundamental things that I didn't understand - that the motors may have completely different P values even if they're identical motors.

Again, thank you for taking the time to answer all my questions; it's very much appreciated! Happy New Year!

Nick.

[Basicmicro Support]

Different values but usually in the same ballpark if they are the same model motors running the same load.