Project - PID on Lee Pro 4 20 furnace

[Alchemist]

I finally got my PID controller finished today, and took it for a test run. Works pretty well, but the temp drops from the set value of 725 down to about 685 whenever I add an ingot to the pot. The ingots are roughly 1lb and preheated on the hot plate to about 365 degrees. I was surprised at that much of a temperature drop with a preheated ingot going into the pot. Recovery of set point temperature was fairly quick. The PID seemed to regularly overshoot temp by about 5 degrees. I noticed that the output voltage was turned off below the set point, so it may just be something to do with the pot itself.

Overall, I'm pleased with the results as the temperature of the pot seems more stable. The next test will be with the Lee 4-20 using the ladle.

[Frozone]

No that is how it's supposed to work.

I have one I trained to 3/4 of a pot.
From dead cold and set at 700º, it'll shut off ~ 620º and 'coast' to within a few degrees of 700, usually about 702.

You can get you're PID to do it too.
Reset the AT parameter to 'learn'. (It locks itself each time it finishes). Bring your pot up to temp.Have about an "average" amount of lead in it (like I said I used 3/4 full).
Now press on hold the AT button until AT flashes on the display.
Walk away for about 30 minutes. when you come back it'll amaze you how accurate the thing is! It'll stay that accurate as long as the amount of lead is around the 'average'.

[boltons75]

Got mine wired up today to make sure all was working well. So far so good, now I just need to tidy it up a bit, and wire in the fan to the power and it'll ready to go. Thanks for the idea of using the computer power supply, it worked great, and was free since I had an old tower that was in the toss pile.

Always carry, never tell.

[Jailer]

Well, I finally jumped on board. Just ordered everything I need for my PID project.

Now the waiting game until it all arrives.

[boltons75]

Here's my pid controller, took an idea from someone here and gutted a computer power supply for the case. It has a thermocouple plug on the back, I'm using it for my lead pot and my lam2 heater.

[Jailer]

Now the waiting game until it all arrives.

Talk about fast shipping!!!

Got all my stuff today and threw it all together. Works like a charm.

I can't believe how much easier this makes casting not having to keep one eye on the thermometer to keep the temp in check.

Thanks Cranium for posting on this. Every day I'm amazed at the multitude of helpful things I find on this site.

[nspctr7]

Thanks Cranium, you helped me find yet another use for an ammo can, but more importantly thanks for posting the idea, setup and everyone's great input.

One pointer to everyone, if you plan to source a cheaper PID on Ebay, make sure you check that it displays the units you wish to work with. Many of them show Celsius and not Fahrenheit, with no ability to convert between them. I learned the hard way, (had to buy 2) My second one, I ended up going with the easy to work with Aubriens PID which you can display both.

[nspctr7]

Picture of my new ammo can

[boltons75]

Nice case there.

[ChuckS1]

The electrical plug looks surprised...

[Mal Paso]

So as not to be outdone in the Computer Recycling or SSR Cooling I present this.

The Intel CPU Cooler had been on my desk for at least 3 years, too nice to throw out with a solid copper core around a very cool aluminum extrusion. Never used, it was upgraded before I put the computer together with some fancy Heat Pipe aftermarket cooler. It looks cool even though totally unnecessary. At least I got it off my Desk.

[shotgun sherry]

I want to thank every one here. If it wasn't for all of your posting here I would have never got
My PID working. Thanks again

[dave_g]

Okay, about to order some parts and build one of these. If I use an old extension cord for the external wiring, what do I do with the ground wire? Should I ground the case I'm using? Should I just ignore it? The wiring diagrams only show the live and neutral wires.

[Mal Paso]

Okay, about to order some parts and build one of these. If I use an old extension cord for the external wiring, what do I do with the ground wire? Should I ground the case I'm using? Should I just ignore it? The wiring diagrams only show the live and neutral wires.

If the case is metal attach the ground to it. As well as the output socket ground if it has one.

[dave_g]

Thanks, the case I got is metal. I'll hook wire it up as soon as the PID shows up.

[Ultravox]

Well I have to say there are some great ideas here. I got half way through the thread and stopped to order a PID, thermocouple, and SSR.

I have a bunch of old PC power supplies around and that looks like a great enclosure.

I'll do a write-up and post it here when I'm done.

Thanks for all the info!

[Powellcole5490]

Can one of you electrical/PID geniuses explain what settings I need for the PID. I'm trying to get my two neon lights to light up when my alloy is too hot or too cold. Besides that I would like to get my PID to control the temp as accurate,y as possible. I've tried reading over the manual but clearly I'm not smart enough to decipher what I need between all the different settings (a, t, pb, ep2, lock,etc, etc, etc) any help would be greatly appreciated.

[Frozone]

What Controller are you using?? Auber 2352?

The actual PID settings are pretty good from the factory. But you need to train the unit.

I assume you have the alarm circuits wired correctly.

from the top of SET mode.

ALm 1 = absolute high limit alarm (I set at 900)

ALm 2 = absolute low limit alarm (I set at 500)

HY-1 = deviation high alarm (I set at 5) this is how far above set temp to trigger alarm 1

HY-2 = deviation low alarm (I set at 5) this is how far below set temp to trigger alarm 2

HY = hysteresis best at 0.3 unless you Must change it.

At = learn mode. if set to 3 you can't train the unit. Set to 1 to enable training mode. You must make this change every time you want to retrain the controller

I =
P =
d =
don't change these let the unit it make changes by training it.

Sn = input type - should be 0 (zero) for a K type TC

dP = decimal point displayed - set to 0 as you really don't need temp displayed to less than a degree.

P-SL =
P-SH =
don't change unless needed.

Pb = input offset, put TC in Ice water use this to zero the displayed temp to 32º.

op-A = no changes

OUTL = 0 - allows unit to turn off.

OUTH = 100 - allows unit to run at 100% on

AL-P (default = 17) alarm options. set to 21 to enable both high alarms on ALM1 and both low alarms on ALM2.

COOL (2=disable alarms until set temp reached), (8 = degrees in Fahrenheit)
10 (2+8) = degrees F and disable alarms. 2 = disable alarms and degrees C
I prefer the alarms active from startup and degrees F so I use 8 as the setting.

You can ignore the resr of the settings.

[Powellcole5490]

Frozone, you are the f-ing man! THANK YOU!

[Powellcole5490]

Ok so I played around with it a little bit but I still cant seem to get the neon lights to light up. Just for testing I have the target temp set at 80 so I can use body heat and ice water to manipulate the temp. I've got my lights hooked up to terminals 1, 13 for alarm 1 and 13,14 for alarm 2. The small lights for AL1 and AL2 located on the PID unit work just fine but my other neon lights do not. Suggestions?