Inverting the direction of a Motor

[Alan Anderson]

Originally Posted by GRS

pwm01 = 255 - pwm01

That should be 254, not 255. The valid range of pwm values is 0-254, and the "neutral" value is 127.

Originally Posted by Tom Bottiglieri

PHP Code:

pwm01 = p2_y;
pwm02 = ~p2_y; 


This flips all of the bits, so realistically it does the same as (255-pwm01).

True, but that's not the desired function.

Originally Posted by SlimBoJones

These might seem unrelated, but be sure to calibrate your speed controllers when you do this.

The reason is, the Victors don't seem to behave exactly the same backwards and forwards out of the box. We've noticed that setting a PWM to 178 and 78 don't produce close to the same speeds in opposite directions... until you calibrate the Victor.

Your example numbers aren't quite right. 178 is neutral plus 51, and 78 is neutral minus 49.

But you're right about the problem -- the Victor factory calibration is a little off from the IFI pwm outputs, with its actual neutral point at more like 132. That makes your forward value at plus 46, and your reverse value at minus 54...until you calibrate the Victor.