I have Pololu Dual G2 High-Power Motor Driver 24v18 Shield for Arduino (item 2518) and Pololu Dual MC33926 Motor Driver Shield for Arduino (item 2503). Both have current measurement feature. In both boards, I see -50mV with multimeter on pins A0 and A1 when it does not work when no current flows. In the data sheet, it is stated that the outputs are active when the H bridge is driven. However, when the motor is driven by the h bridge (item 2503), I can read the current correctly at both A0 and A1, (820mV which means 1,6A) while I cannot read the correct current (item 2518). When I measure the outputs with a voltmeter, I do not see the correct value. With multimeter A0 goes from -50mV to -10mV, A1 goes from -50mv to +20mV…
What should I do to measure currents correctly.
Hello.
I am sorry to hear you are having problems with the current sensing on your dual high-power motor driver shield. The output of the current sense should be 20mV/A plus an offset of approximately 50mV, and you definitely should not be reading a negative voltage. Could you send me pictures of your setup that show how everything is connected, including your multimeter? Also, if you are using an Arduino as your controller, have you tried running the Demo.ino example from our Arduino library to see what it is reporting?
Brandon
I am using STM32F401 Re. This Ardunio compatible motor driver has pin compatibility with STM32F401. M1PWM, M2PWM, (as timer) M1DIR, M2DIR, M1SLP and M2SLP GPIO output, M1FLT and M2FLT GPIO input. I defined M1FLT and M2FLT as GPIO input. ADC0 and ADC1 were defined in A0 and A1. When A0 is connected to the voltmeter input of the multimeter and the ground of the multimeter is connected to the ground, the value I read from pin A0 is -50mV. (when the motor is not running). A1 is the same. I will try the motor driver and STM board separately.
