Re: PID question


John Popelish wrote:
hondgm@xxxxxxxxx wrote:
John Popelish wrote:
hondgm@xxxxxxxxx wrote:

Well, not really. I was going to have only one DAC that provides the
ref voltage for the regulator, then use that, along with the current
sense value, to limit current. Remember the PID is being done in a
micro, and the only analog I/O is one DAC out and one A/D measuring
load current.


I lost some of those details.

So the DAC provides the analog signal representing the
output of low selector, (the setpoint for the analog PID
current controller), and the ADC provides the load voltage
measurement into the software PID voltage controller.
You will still need an analog current measurement to provide
feedback for the analog PID current controller.

The only question left in my mind is whether or not the
micro has the bandwidth to perform the PID voltage
controller and low selector with adequate response.

Actually, I have an ADC that reads the load current. I also have one
that reads load voltage, which is a little redundant. The micro is 16
bit, with a 100ksps A/D and a some DSP type functionality. It seems to
handle it ok; it's just that some loads causes the voltage output to
jump all over the place. For example, pure resistive loads are fine.
If I put a small motor on as a load with some current limiting, it has
problems. The voltage output jumps all over.

.

Relevant Pages

  • Re: PID question
    ... ref voltage for the regulator, then use that, along with the current ... So the DAC provides the analog signal representing the ... (the setpoint for the analog PID ... You will have to use the analog signal it digitizes as the feedback for the analog PID current regulator. ...
    (sci.electronics.design)
  • Re: Will Radio Engineering be QMs worst nightmare?
    ... See what kind of voltage gets produced by 150 watts ... I am thinking of an amplifier that is turned on with no load. ... > don't increase because the load resistance changes. ... What kind of amp. ...
    (sci.physics)
  • Re: PID question
    ... An analog input on the micro will monitor load current. ... controlling the set voltage. ... Since you are dealing with a loop you should analyse it ... Ki is an integrator which means its response falls at 20dB/decade and it has ...
    (sci.electronics.design)
  • Re: Flyback transformer design confusion!!
    ... When applying a constant DC voltage across a resistive ... load, just *how* can I increase the power into that load, other than by ... Iout is to change the resistor. ...
    (sci.electronics.design)
  • Re: HELP! Onan Emerald III No AC
    ... I replaced the fuse and let it sit for a minute. ... motor purrs along just fine and does not blow the fuse. ... I applied the load and the surging was ... 'transformer regulated' set - no electronic voltage regulator. ...
    (rec.outdoors.rv-travel)