Quote:
Originally Posted by philso
Please confirm that you are using a DVM to measure the output of the motor controller.
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You can also use a DVM to measure the PWM signal command going into the motor controller.
Let's say the PWM command is 5ms period, 1.5ms pulse width, and 3V pulse height (see note below).
If your DVM is set to measure average DC you should get a reading of 1.5/5*3 = 0.9 volts
Note:
When commanded by a roboRIO PWM output, the pulse height at the motor controller inputs will vary from ~1.7 volts to ~4.8 volts, depending on the type of motor controller (the load is different). Here are the rough calculated pulse voltage and mA numbers based on info I've been able to gather and test so far:
Vic888 = 1.7V 10mA; Spark = 2.6V 7mA; VicSP = 4.8V 0.6mA;
If anyone would be willing to scope the waveform on the PWM input terminals of the above motor controllers (while being commanded by roboRIO) to confirm (or correct) these numbers it would be appreciated.