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Old 04-11-2015, 11:58 PM   #7024 (permalink)
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Originally Posted by MPaulHolmes View Post
It's assuming a 0-5k pot is attached, and also the current sensor. one way to check PWM is to measure voltage from any gate resistor to ground. Well, the ground of the output of the DC-DC CINCON. (also known as the ground of the MIC4451). Measure the voltage at zero throttle, then, give it nonzero throttle, and the pwm will ramp up to 100%, so you should see the voltage climb to around 12v on the volt meter. That's because it's trying everything it can to see some current feedback to match throttle position, but the current feedback continues to be 0.
Originally Posted by jedsmd View Post
For testing you can replace the current transducer with two equal resistors wired as a voltage divider to put 2.5v on the current sense line. That way the controller thinks it is producing a nice steady current and pwm will track throttle setting.
Thanks for tips guys! With that I believe the controller board is working correctly. I was trying to figure out where to stick the ground reference on my oscilliscope and I realized there are many ways to do that incorrectly I had been probing around R17 and Pin 15 on the Atmega. With the 0-5k pot on one of these I saw a PWM duty cycle that kept growing to 100% and I figured the growth was the PI ramp up. This makes sense since my current sensor was not measuring anything that it would rail the pwm.

Now, I can't install RTD explorer for some reason.

edit!! - I go back to try to reinstall and post the error here and RTD explorer installed! So excited!
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The Following 2 Users Say Thank You to Articus For This Useful Post:
jedsmd (04-12-2015), MPaulHolmes (04-12-2015)