PID Question

[Mike W1]

I switch my PID between my furnace and my luber heater. Autotune of course will change the settings of P,I,and D. I've recorded these a couple of times for my own info.

Question being when I switch from one unit to the other and reset the temperature would it make sense to also get in there and change those PID values to about where they're gonna end up anyhow and thus speed up the autotune process? Any pros or cons to that thought?

[el34]

Proper values for whatever is being controlled is what gets quickest up to temp with minimum overshoot. I'd suggest just trying it with the values you use the most and see if it's acceptable on the other thing you're hooking up to.

[Mike W1]

They're fairly different between the furnace and the luber heater. I seem to remember the auto tune taking quite a bit of time when switching units. Very little cycle swings once it's warmed up and auto tuned to that unit or from a cold start if it's been tuned to that unit. Think my question may have answered itself.


Proper values for whatever is being controlled is what gets quickest up to temp with minimum overshoot. I'd suggest just trying it with the values you use the most and see if it's acceptable on the other thing you're hooking up to.

[bangerjim]

manually enter the values. Auto tune will take probably longer than you are running it!

Auto tune will tweek it while running if you miss a bit.

In the equipment I sell, those are called "batch recipes" and are uploaded from a computer or USB stick into the controller(s)......much more sophisticated devices than that tiny postage stamp Auber-like thing most people on here seem to gravitate to.

bangerjim

[OuchHot!]

Have you tried to see if just letting the lube heater wing it on the (obviously not optimal) setting for the furnace? I am asking because I would personally not need precise control of a lube heater. When I first played with some pid, they controlled a furnace full of lead or a hotplate with no load on it reasonably. Or at least better than what I got with stock pro-melt and lee 4-20.

[Beagle333]

Mebbe build another PID? :bigsmyl2:

[dikman]

I'm with Beagle :2_high5:. For the relatively low cost of building one (and a cheap PID will be more than adequate) I'd build a second one. It will save you a bit of messing around each time you change and in the long run be worth it.

Much better than having to change the PID settings each time.

[el34]

......much more sophisticated devices than that tiny postage stamp Auber-like thing most people on here seem to gravitate to.

bangerjim

That would be me.

[Beagle333]

And me!:mrgreen:
http://i613.photobucket.com/albums/tt214/shutupandjump/PID/pid006_zps50486383.jpg

[Mike W1]

I'd imagine I spend about a whole minute setting the temperature and changing the PID value. Not worth building another unit for that's for sure!!! Besides I don't use the furnace and the lubrisizer at the same time ever. I'll stick with changing the settings manually when I switch units and then let it autotune.

Mines a Auber 2352 that's easy to change settings on. Suppose it's probably Chinese (what isn't) but it read in F and the instructions were in English. Worth the extra bucks I paid for it to me.


Have you tried to see if just letting the lube heater wing it on the (obviously not optimal) setting for the furnace? I am asking because I would personally not need precise control of a lube heater. When I first played with some pid, they controlled a furnace full of lead or a hotplate with no load on it reasonably. Or at least better than what I got with stock pro-melt and lee 4-20.

[el34]

Sounds like you're good to go.

[dikman]

Fair enough, Mike. I guess I just like building things - I've got three, but in reality I guess I only really need one [smilie=1:.

[jason f]

Mebbe build another PID? :bigsmyl2:

i agree. i built this one for my lead pot, mold heater and annealing/powder coat oven.

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