Hello Pololu People,
Wondering if someone here may have experience with measuring PWM controlled motor current? We are using the the 50:1 Metal Gearmotor 37Dx70L mm 12V with 64 CPR Encoder (Helical Pinion) - Pololu item #: 4753. The motor is coupled with the Dual TB9051FTG Motor Driver Shield for Arduino - Pololu item #: 2520. I have been evaluating the ACS711EX Current Sensor Carrier -15.5A to +15.5A ( Pololu item #: 2452), and able to measure static, non-PWM, current accurately. However, with PWM controlled motor operation, the measured current is erratic given the obvious nature of PWM.
I see that a RC low-pass filter may be necessary to average the PWM controlled current. Perhaps this may be further added to the ACS711EX Current Sensor VOUT? I noticed that the ACS714 Current Sensor Carrier -5A to +5A (Pololu item #: 1185) mentions a RC low-pass filter already built into the design, perhaps this may be an option to consider? Wondering what you may recommend for a PWM controlled motor current sense solution? Is there a hardware solution available or is extra circuit building required? If possible, I would rather buy a device which incorporates all features rather than custom circuit making, especially as we may be offering many PWM motor controlled systems in the future, so a lower part count is best.