Re: PID question

John Popelish wrote:
hondgm@xxxxxxxxx wrote:
(snip)

On your
next post where you say that "you must allocate several samples to your
desired response time", do you mean that I should be taking an average
of several samples before feeding it into the PID loop?
(snip)

Not at all what I think he meant.

Each sample you take must be used as quickly as possible, to minimize time delay inside your control loop.

I think what he meant was that it takes many cycles of your sample and control algorithm to restore the system to setpoint, after a disturbance, so just because you can sample and cycle your program 100k times per second, don't expect to recover, completely, from a step current error much faster than 10 to 100 sample times (100us to 1000 us), especially with load impedances other than for what the control loop tuning was optimized.

Yes, that's exactly what I meant.

It would be interesting to see what kind of speed can be achieved with the discrete-time loop. If/when the OP completes the project, perhaps he could post some results.

--
Regards,
Costas
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