Pid temp control finished !!!

[ph4570]

I lashed one of these together using the same controller as Horsemen. With the default PID parameters and a full 20 pound Lyman pot it held 800 degrees +/- 10. I was not too impressed with this as I was not casting so the lead level was constant. I raised the PID dampening constant from 0.2 to 0.4 and then it held 800 degrees +/- 2 degrees -- not bad. However, still not casting so it will be interesting when the lead level changes. It is a lash-up at the moment. When I get it in a connectorized box this weekend I will test whilst casting.

Does anyone else have favorite PID parameters for a setup like this.

[mike in co]

well you sorta answered my question...a big pot and temp control.( 20 lbs)

let us know how it goes.


thanks
mike in co

[RP]

That is one fine looking peice of workmanship I would like to say. But I got one ? when you make it to the lead it kind of goes down hill I think you should now build a pot the one you got dont match your control.

[No_1]

Just got mine done also. I have the lee pro 20-4. I use the SYL-2352 PID with the same SSR and thermocouple then used an old project box that I modified. For the mount I bent a 1/8" piece of aluminum, separated the pot/back from the baseplate and sandwiched the 90 degree plate between them. As a test to see what would happen I set the controller to 825 degrees and had about a 10 degree variance once it was up to temp. I might adjust it to get the variance down to less. I did pour a 3 lb ingot from it and the temp held but when I dropped another 3lb ingot in, the temp dropped about ~200 degrees and took about 6-7 minutes to get back up to 825. Once I cast a load of boolits I will see what happens.

How did you adjust the PID to get a smaller variance in temperature?

Robert

[ph4570]

Ah, what was I thinking? My pot is a Lee 20#er not a Lyman.

No 1, to get the variance down I changed the dampening factor from .2 to .4. If you do not have the instructions they can be downloaded from:

http://auberins.com/

When I get it all boxed up and the thermocouple mounted I will post pictures.

[ph4570]

No 1,
I forgot, I also ran the "auto tune" function of the controller first with the default parameters and then again after I changed the dampening factor.

[hunter64]

I was just thinking that you could use this PID controller to stabilize the temperature on a Lubber. You would have to play with it a bit at first but once you found the temp to keep the style of lube just right away you go. You would just set it and forget about it, no more plugging in and then unplugging all the time.

[JudgeBAC]

I am interested in this project but my knowledge of things electrical would fit on the head of a pin. An electrician friend of mine is willing to help. I supplied all of the photos and diagrams which helped but for general information please describe what plugs into what and how does it work.

After reading all of the various threads I still don't understand how this device ends up controlling the thermostat on the electric pot. Help.

[Willbird]

The thermostat in the pot is not controlling the temp any more.

Bill

[JudgeBAC]

OK, then what does and how does it work? I still don't understand what plugs into what.

[Willbird]

The PID controller reads the pot temp with a thermocouple which plugs into the controller, and it turns the element in the pot on and off to control the heat. The element in the pot will be wired to the PID temp controller which usually has a built in solid state relay.



Bill

[daboone]

ebay has this PID temp controller for $37.50 with free shipping. Will this do the job for a Lee Pro20?

http://cgi.ebay.com/Dual-Digital-F-C...item33565e8d7e

[lurch]

As far as I can tell from trying to read the sticker on the side in the one photo and comparing it to the model options in the manual, it might (caveat below) do just fine. You will need a solid state relay to go with it though. If you use a reasonably sized metal enclosure, the enclosure itself will probably be a sufficient heatsink if the SSR is mounted directly to it. Otherwise, a separate aluminum fin heatsink will be needed as well.

Caveat - The thing is set up to read to 400C or about 750F. That is the only possible hitch I see at the moment. If you do anything that might need to go higher (say casting in some aluminum molds with smallish boolits) you might not get what you want.

[gvanzeggelaar]

Thanks a bunch for the info. I have one question.

Can one PID control the temperature of two different elements. For arguments sake say if I want one element at 400F and another at 800F can this be done with one PID controller, two thermocouples and two ssr's?

[felix]

The answer is Yes because the computer typically used is easily fast enough to handle a hundred. There has to be memory and multiplexing switching circuits to do with multiple external devices. Check on the specification of the unit you might purchase for this capability. Minimum bucks are around 100 at least. The best are around 1500 bucks. ... felix

[uncle joe]

I understand that all the new electronics would be nice on a pot, but why?
How close does the built in controller on a lee 4-20 pot keep the soup? I don't have a thermometer, so I have no idea how much one varies. But it looks like lipstick on a pig when you add 150 bucks for a controller to a 50 dollar melting pot. It looks like it would be cheaper to buy another pot to melt the ingots and mount it over your casting pot so as not to reduce the temp trying to melt a new ingot while your casting.
Someone that has checked a four twenty pot tell me how much temp swing they have during casting (not melting ingots). I may need to scratch up some components. I'm working at a factory that throws away a lot of good stuff sometimes and may need to watch closer.
UJ

[kbstenberg]

I am like Judge BAC with electrics. I can understand what the system does but i am unable to build by an electric diagram. Could someone post pictures of all necessary components wired together so i can see all the wiring layed out. I can build it myself if i can see all the parts layed out.
I mite have missed something. Could someone list all the components an describe exactly what they do!!! I can build anything out of wood, but try to do something electrical an i WILL electrocute myself.

[lurch]

The Lee pot varies a good bit during a casting session, especially as the melt level changes. Don't quote me on this - I don't remember for sure and am shooting from the hip a bit - but I think I was seeing 75F'ish from the top of the pot to the bottom. It was enough to make me look for a better way at any rate...

The cost of the controller, relay and thermocouple to add to a Lee pot to make it PID controlled can be quite reasonable when you consider the improvement made in the temperature stability. I get better than 5F stability with the one I put together. If you get it all from Auber, figure on:

Controller - $36
SSR - $15
Thermocouple - $5

Add in some things like a plug, terminal block (nice but not necessary for enclosure wiring), shipping, etc. and you are at about the cost of a new Lee pot (~ $65 before shipping). The enclosure to mount the controller, relay & plug can run anywhere from free (busted piece of something that you can salvage from) or as much as you care to spend depending on what you get. I went the "free" route. If you already have a Lee pot and want something with better temperature control, you can either fork out another $65 - $75 and a little time, or spring for a Lyman or RCBS or Wage or.... I doubt that one of those (even used & abused) could be had for the price of upgrading the Lee.

[uncle joe]

sounds like I need to keep an eye on the scrap pile for a while.

[kbstenberg]

I just found a thread on the PID that answered a lot of questions. It had complete directions for putting a pid together as well as pictures for the process.
It came fromBig Tom the link is http://www.susanminor.org/forms/showthreads.php?t=315
This is the first time i have tried to show a link addres so if i am wrong sorry.