Quote:
Originally Posted by Al Skierkiewicz
Allen,
In both controllers, the calibrate feature conforms the travel of the joysticks to the controller. The only reason that you would not receive a green following a calibrate is that the joystick is not returning to the same value at which it was calibrated. Are you using a calibrate routine in software or the full travel of the joystick when calibrating?
Now, there is always the possibility that the green LED driver is defective. Do you ever see the LED come on green? It should flash Green/RED when the calibrate mode is active. It should flash Green/Yellow when the calibrate has been successful. Remember that the Jags have a 15kHz output switching frequency and many meters will not measure accurately at that frequency. In addition, Jags generate a reverse pulse to charge the bootstrap cap when at full throttle, this will also generate some error.
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Al thanks for the insights,
I would have expected the calibration to work as well, but we retried it a couple times with the same result. We know the calibration joystick is outputting -1 through 1 to the jaguars because we are watching the print statements. Even if calibration worked, it still doesn't explain how we started getting bad PWM values outputting from our control system. They used to work and we hadn't recalibrated them before this.
The lights on all 9 jaguars are blinking green for forward but none of them will give a full forward voltage even after calibration (or go solid green to indicate they are getting full forward). We didn't calibrate to the VEX controller but we may try that.
We moved our drive train back to CAN (used it previously in the year but stopped for various reasons) and we can get full forward voltage with CAN.
This problem is really baffling. I'm thinking the PWM output isn't symmetric (I'm assuming, we'll check tomorrow with an oscope). This would mean the calibration routine doesn't correct only one side to have a smaller range.
If that is true, I’m still not sure of the source of the issue. The only thing we haven't changed is the cRIO itself. (We don't have a spare).