PID-filter routine (2nd try).

[HenrikOlsson]

Hi,
OK, lots of information here and I'm having a bit of a hard time following it all but here are a couple of thoughts.

Since you have the pid_OutClamp set to 240 and a proportional gain of 1 it means that the output will only "swing" when the CHANNEL1 variable is above 240 (because SetPoint is hardcoded to 480). If it's anything below 240 then the error * Kp is more than the clamp value so the output saturates. For example, if the CHANNEL1 value is 235 the error will be 480-235=245, the clamp is 240 so that's what you'll get.

If you do a step change of the PWM dutycycle, (ie. if you go from 20% to 80% dutycycle) how fast does the current in the system change?
I mean, you have a PAUSE 10 in there meaning you're only running the loop at 100Hz, it also looks like you're writing to EEPROM in the GetAD routine, which also takes around 10ms per byte so then we're down to around 50Hz. I'm not sure but 50Hz sounds awfully slow for a current control loop. You say that you've tried without any PAUSE at all but I still think you have around 10ms delay due to the WRITE instruction in the GetAD routine.

Not sure I understand what you mean with there is a 50% duty cycle between a full on clamp and whatever the pid value should be. Can you clarify?

May I suggest you try to implement this on something slower to begin with? Try a temp-sensor tightly coupled to lightbulb driven by the PWM signal for example - I think it'll make it a lot easier to begin with.

/Henrik.