Feedback current reading!Help

Support Motor controllers/drivers and motors
1

HI guys;

we are working on pololu-Dual motordriver MC33926 to control two wheel balancing robot.
when we measure the FB using serial port it is very law value which we didn’t believe it is true value.
and when we check using oscilloscope we found out that the signal from Fb is negative singal(but right value).
so my question is how on earth the pololu-Dual motor driver gives a negative voltage feedback as it cannot measured by TTl device ?would you suggest me how i should measure feedback current using Fb pin out from the board.

Thanks for the Help
Eyob

2

Hello, Eyob.

The current sense feedback should not produce a negative voltage, so either the board is damaged in some weird way or you are measuring the voltage incorrectly. Can you post a screen capture of your oscilloscope measurements and a picture of how your probes are connected to the motor driver? Have you used a multimeter to see how much current your motor is actually drawing? A description of your overall system (e.g. motor and power supply specs) with pictures could help.

- Jeremy