Re: Odd PWM problem (Can't get full green)
 

Well it looks like it's a problem with the factory calibration and today we were able to calibrate it to give full forward voltage. I'm not sure why it worked today and the past two days it didn't but whatever.

Here are the oscope outputs
Neutral Jaguar


Full FWD Jaguar


Full REV Jaguar

Re: Odd PWM problem (Can't get full green)
 

Victor PWM outputs in case anyone is interested.

Neutral Victor


Full FWD Victor


Full REV Victor


Thanks to everyone that helped diagnose this problem, still not sure why the factory calibration was ever messed up.

Re: Odd PWM problem (Can't get full green)
 

I had not realized that the cRIO puts out 200Hz (5ms period) PWM when in Jag mode.

Can someone please confirm that this is correct operation?

Re: Odd PWM problem (Can't get full green)
 

That is correct operation. The Jaguar uses a faster and wider signal to push more updates per second with higher resolution.

Re: Odd PWM problem (Can't get full green)
 

Thanks Eric. I need to update the PWM Generator app then. I presently have the low limit set to 10ms.

Re: Odd PWM problem (Can't get full green)
 

It should work with fine with longer pulse windows. The frequency is unimportant, so long as it is quick enough to not trip the watchdog, and slow enough to still be legible. The width is the important factor.

Re: Odd PWM problem (Can't get full green)
 

Understood. But I want to mimic the cRIO's signal as closely as possible.

I forgot to ask: what period does the cRIO use for the Vic PWM signal?

Re: Odd PWM problem (Can't get full green)
 

5ms on Jaguar, 10ms on Victor, 20ms on Servo. There's some nice comments in the PWM source code.

The comment says jaguar is actually 5.05ms, but I can't view the scope plots to confirm.

Re: Odd PWM problem (Can't get full green)
 

Thanks Joe.

I've updated the app, if anyone's interested.

Available here.

BTW, an earlier version of this was used in June on an old Compaq DeskPro 2000 running FreeDOS 0.84 to run a Vic driving a CIM on a dynamometer. Oscilloscope traces of the waveform showed the pulse width generated by the app was accurate to within +/-0.001 milliseconds of the operator setting.