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Topic: PID tuning - what fun! (Read 1 time) previous topic - next topic

mmcp42

some of you may have seen the reflow oven I'm working on
it's ok but not great
I'm trying to get to grips with PID tuning

there are basically 4 temperature ramps
each has different target temperatures (clearly)

I'm tinkering with the PID settings for each ramp
then had a thought (it happens once in a while)

as well as setting new Kp, Ki and Kd, should I also initialise the PID software
something like setting pidIterm to zero?
or will it all come out in the wash after a while?

cheers
Mike
there are only 10 types of people
them that understands binary
and them that doesn't

retrolefty

I would be surprised that you need different PID tuning requirements for each of the target temperatures. The tuning is usually just to get a stable response for the system as a whole (heating element power, system heat loss, system heat dissipation rate when turned off, etc. One set of tuning rates is probably the best route to go and then issue setpoint changes gradually if you want to slow down the ramping rate from one value to the next. So setpoint change managment might be a better way to go then trying to build in the ramping timing rate for each 'step' via PID tuning values?

Lefty

mmcp42

ah fair cop guv
gave that a try finished up with this profile
doesn't look too shabby

opinions?

cheers
Mike
there are only 10 types of people
them that understands binary
and them that doesn't

CrossRoads

#3
Feb 17, 2013, 11:34 pm Last Edit: Feb 17, 2013, 11:40 pm by CrossRoads Reason: 1
Looks pretty good.
How do the hold times compare? They are a little hard to read on my laptop.

Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.

Coding Badly


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