P.I.D. Temperature controller

[lwknight]

I have read just about all the stickies and most everything posted in the last few months on this forum.
I had no mentor or internet when I started casting and reloading and missed a lot of clues of fine tuning the art for sure. So many time I read others questions and think about it and know that . I have been there and done that. I just never made a verbal thought about it.

I did not know that a PID temperature could be bought for than some hundreds of $$$.

Thanks to the inmeasurable wealth of shared resourses in this forum , so many things that I knew but had not put to a cognizant thought have cleared up.

This 16/4 controller that I got for 44 bucks along with a $11.95 6" probe from Auber Instruments is worth every penny.

This thing is way COOL!!! It actually learns how to operate my lead pot and keep the temperature right on the money. It learns just when to shut off when I add ingots and when its just a normal warm up cycle.

These are simple to wire up too.

I guess this my first big WAHOO!! for posting on this forum my first new thread.

Now, everyone go out and buy a pid controller.. just joking......

[Big Tom]

Yep, these controllers are great - I actually use mine with two probes - one for the lead pot and one for my Bradley smoker. Made the probes plugable and it works like a charm - keeps the temperature in a +- 5-10 degree range.

Tom

[Barnowl]

LWKnight,

Which controller did you buy?

Kevin

[gary0529]

lw,

in addition to the controller #-I will assume it is the one that cost $44.50 - what thermocouple setup did you go with and how did you attach (if at all) in pot.
I typically use bottom pour pot and really did not want to drill and tap a hole in pot but could be talked into it if it worked for you.

Thanks again,

Gary

[lwknight]

I just found these replies then I had to look and find the instruction page to get the part numbers.

The one that I got is 1/16 DIN PID Temperature Controller (SSR control output) Model: SYL-2352
My logic was that I did not need anything fancier and this ond has a current temp display separate from the setting display. This one already has a built in SSR (solid state relay) that can handle 10 amps and by my figuring. The lee pot 700 watt heater needs 6 amps


The thermocouple was Model: WRNK-171 It has a 6" probe and is good for 900 degrees.
The rep told me that the sensor is in the tip and that the thing could be bent but, I'm leaving mine straight.

I plan to get some thin metal stripping to make a bracket that uses the screw holes in the pot as a support base and mounting the probe right next to the spout.

I'm thinking that in the future I will get another one and use a 24V transformer with 30 amp contactors to actually power the electric burner that I plan to use for smelting.

[The10mmKid]

LW,
If you feel the need for a contactor, drop the 24VAC and just get a 120V model.
Also, unless your using 230V, get a double-pole and only use one side to control the 'hot' side. The other pole will come in handy when the first set of contacts fail.

Guys, please be forwarned, Solid State Relays do not always function well with SSR contacts in the controller. SSR's always leak a small amount of current and sometimes this is enough to 'fire' the main SSR. BTDT.

Our most reliable heating systems are: SSR in the controller and Mercury Displacement relays for the heater circuit.

http://www.plasticservices.com/techtips/contactors.htm

If the controller you purchase can handle 10A, let it do the 6A work. It will be happy for years-to-come. Just be sure to give the controller the ventilation it deserves.

'da Kid

[lwknight]

I was going to use the contactors for a 2.25KW heating coil for smelting.
Setting it up exactly like the A/C condenser unit. Contactors are really cheap
and last a long time.
Double pole will just be for extra safety seeing that cooking lead is not what rangetops were approved for in the first place.

[gary0529]

Thanks for the updated information.
Have sent an e mail off to Auber and will probably place order shortly.
Will update my success? as soon as I get the system up and running.
Gary

[The10mmKid]

I was going to use the contactors for a 2.25KW heating coil for smelting.
Setting it up exactly like the A/C condenser unit. Contactors are really cheap
and last a long time.
Double pole will just be for extra safety seeing that cooking lead is not what rangetops were approved for in the first place.

Carry on, you are on the right track.

Be careful of some A/C relays as they can actually not be double poled as this example shows:

Note that the lower contacts feed straight through the relay.

Also make sure your PID settings don't short cycle the contactor. Generally, 4-6 cycles per/min is the max. Any faster cycling wears on the contacts.

Also for smelting, you may want to try your controller in ON/OFF mode. It will function just like your home thermostat. It outputs on one degree below setpoint, off at one degree above.

Of course PID is the foshizzle,
'da Kid

[lurch]

The one that I got is 1/16 DIN PID Temperature Controller (SSR control output) Model: SYL-2352
My logic was that I did not need anything fancier and this ond has a current temp display separate from the setting display. This one already has a built in SSR (solid state relay) that can handle 10 amps and by my figuring. The lee pot 700 watt heater needs 6 amps

Just an FYI - Assuming that controller is the one from Auber, it does not have a built in SSR. It has an output that will control an external SSR. To use that one you will need to purchase a SSR separately as well as provide some means of providing a heatsink for it.

There are models that do have an internal relay that will handle 10A (i.e. SYL-2342). I would personally go with the one that has the control for the SSR and use an external SSR because the mechanical relay will wear and fail over time. When it fails, you will either need to get another controller or if you are handy with a soldering iron and can get a suitable replacement, replace the relay yourself. With the SSR, there are no mechanical contacts to wear out and the setup should last quite a long time before maintenance is required. If you want to go with the straight mechanical relay output, I would suggest setting the controller up for a relatively long cycle time (something more than the 4 seconds default for the relay output version) to reduce the number of times that the relay will have to actuate. This will prolong the relay life. Either way will work though.

[lurch]

Kid,

Just looking at your picture is appears that the contactor is switching the neutral and the hot is wired straight through. That doesn't look like it's in a setup for controlling a lead pot, but just thought that it might need pointed out. You mention correctly that the hot should be the switched incoming power lead for purposes here. Good post.

[jsizemore]

Kid,

Just looking at your picture is appears that the contactor is switching the neutral and the hot is wired straight through. That doesn't look like it's in a setup for controlling a lead pot, but just thought that it might need pointed out. You mention correctly that the hot should be the switched incoming power lead for purposes here. Good post.

Lurch, I think he's just using that picture as an example. Looks like a contactor for an A/C condensing unit. Capacitor located just above. Probably Carrier or Goodman??

[lurch]

That's how I interpreted it - maybe (probably...) it sounded like I didn't. I just wanted to call out what would be a wiring error if somebody not familiar with wiring tried to copy it exactly for a lead pot.

[jsizemore]

I just wanted to call out what would be a wiring error if somebody not familiar with wiring tried to copy it exactly for a lead pot.

Me 2.

[lwknight]

The contactor in question is 220 and both legs are hot.
Only one leg is switched to allow continues power to the crank case heater that runs on 110. There is not a nuetral through the contactor. Just because a wire is white don't mean that it is not hot.

Thats why I only was bragging about how cool the pid controller was and made no statements about how to wire anything up. CYA guys.

If anyone gets a controller and needs help with wiring and circuitry I will help but, in private communication only.

[lwknight]

I got the model SYL 2342 with 10 amp internal SSR that has no power of its own. If someone got model that does not have the internal 10 amp SSR , its not such a big deal to get an extrenal SSR or contactor. In fact it might be better in the long run anyway.

[The10mmKid]

All excellent advice.
I just didn't want someone thinking they can stop at a supply house and pick up a 'standard' condenser relay.

At <$50, I'd go with the internal SSR on a 700W LEE 4-20 pot and dispose of it when it dies (or latches on). Don't forget, even with a disconnected bad output, you still have a great temperature monitor.

I guarantee you'll have a harder time finding that mini SSR verses any circuit board replacement work.

I'd like to know if the Auber output relay is in a socket like the top-of-the-line Omron, EuroTherm controllers?

'da Kid

[lurch]

I'd like to know if the Auber output relay is in a socket like the top-of-the-line Omron, EuroTherm controllers?

Fat chance of that. I have not actually pulled one apart and don't know for absolute certain...but... These things are Chinese. If you think for a moment that they are going to put one iota of something in there that is not absolutely essential to having the thing work, think again. I've had too much experience dealing with Chinese engineering & engineers with my day job to think something like a relay socket would be in there. They are all about how cheap can it be made - sometimes to the point of serious reliability compromises. That's part of the root of my wanting an external SSR for the control. The internal mechanical (the internal PID output relay is mechanical - not a SSR) relay output would be one of the most inherently unreliable items in the thing to start with, even with a top notch component. After Chinese cost reductions, which I'm sure this thing went through at this price point, I simply don't trust that relay for the long haul. If it's being sold on the American market for $45, you can bet that the actual manufacturing cost is at most $10, if that.

[lwknight]

I started to smell the pid controller getting hot and as was suggested by others I got a contactor and transformer for about $8.00 each.
Once wired in the PID only operates the contactor coil which is very low power.

I did not go with the external SSR because you cant just get one anywhere. These A/C contactors are readily available from any hvac supply to the public and are designed to be easy to replace.

There was some discussion about the life of the contactor if the cycle time was too short. My controller cycles pretty slowly even with 1" melt in the pot and even slower when the pot is filled.

The 700 watt heater is not much of a load on the 30 amp contactor that should last for many years. If not, big deal. I can change it in 5 minutes and it costs like 8 bucks.

[lurch]

My controller cycles pretty slowly even with 1" melt in the pot and even slower when the pot is filled.

Sounds like you have things set up as a simple on-off control scheme as opposed to using the PID control scheme. That should be the easiest on the mechanical relays/contactors. If you are using the PID control capabilities, the contactor will cycle every X seconds regardless of what else is going on - unless of course the pulse width modulation routine in the controller is in a "saturated" state where the control output just stays on or off for a while (most commonly during initial heat up).