Programmable PID controller that's user friendly?

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Whatsup

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Aug 25, 2023
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Hi all,
I am planning to build a heat treatment oven. Could anyone recommend me a PID controller that is programmable and still somewhat user friendly? I would love to hear your preferences and which ones to avoid. Is there much difference between them btw? Or are all of them pretty user unfriendly?
thanks!
 
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Industrial PID controllers tend to assume that whoever is programming them has some idea of what they are doing. This can be a bit awkward for the beginner.

Having used many controllers over the years, the best advice I can give is to download and thoroughly read the manuals for each one you are considering. If you can't freely download the manual for one, stop considering it. If you can't understand at least most of the manual, stop considering it. Once you have a shortlist, check whether each supplier has tech support in your language and timezone. If not, stop considering that controller.

The reason for downloading the manual is that, if you run into a problem, you can call for help, here or elsewhere online, with a link to the manual and a reasonable prospect of someone, who knows controllers generally, being able to help. Without the manual, they can't help. If the manual can only be accessed by signing up to a lifetime of spam, that ain't gonna happen and they can't help you either.

Initially, I'd suggest a fairly basic controller (no Ramp/Soak) with pulsed DC output to drive an SSR (maybe dual SSRs in parallel if your design calls for this). There's a learning curve and added complications don't help. Don't be too tidy when you wire the controller (this seems to be something that many folk who make knives struggle with). Different controllers have different connection layouts. If you leave an extra 3" or 4" on each of the wires, you can upgrade your controller at a later date without having to rewire.

Note that manuals are expensive. Most of the really cheap PID controllers have really poor manuals.

By all means look at kiln controllers, but bear in mind that Ceramics kilns, unlike HT ovens, are more concerned with heat-work than with precise temperatures. Many have a 30-second minimum output cycle time, which will cause the temperature to cycle above and below the setpoint. Make sure the cycle time can be set to 5 seconds or less (I use 2 seconds).
 
Tim has given good advice and he knows his PID controllers. For anything more specific we need to know what part of the world you're in. Filling out your profile is a good start. "IF" you're in the USA I'd strongly suggest an auber pid controller. they have several models, the cheap one is SYL-2362 and is the one I've used for a couple of projects. The AW-SYL-2352 is a Wi-Fi-capable PID controller for a bit more money. Auber is based in Alpharetta, Georgia, USA and has good tech support from that location.

BUT, if you're in some other part of the world other options might be better.
 
Thanks for your elaborate reply Timgunn1962 :). I will certainly take advantage of it!

So basically you recommend a non-programmable PID controller or a kiln controller. If I understand you right you are using a kiln controller that has the option to set the cycle time to 2 seconds.

If I go for a non programmable PID controller will I still be able to anneal air hardening steel? I don't know enough about heat treating to be able to tell :)

I am from the Netherlands btw.
 
Annealing an air hardening steel will require programming the PID with a decreasing rate. That won't be a simple PID.

If you don't have the programming skills or aren't sure about how to set up the parameters, you may want to contact a HT oven supply and inquire about purchasing a pre-programmed knife oven HT controller. These will cost more than a cheap PID, but come ready to use and easily programmable for HT regimes. Controllers like the Set-Pro, TAP, Genisis, and Rampmaster are some of the most common.
You can also buy simple control boxes online and on the auction sites that require very little programming. These may not do rate of heating/cooling steps, though.
 
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I use the Auber PID... They have great customer support and it's pretty simple to set up
 
Knowing myself I would be disappointed with a PID controller that doesn't allow me to do all the things I want. I will be able to program any PID, that's not the true problem. But how difficult is it to program? Will I remember how to do it after a year? - the answer is: "probably not"" (knowing myself). I feel that if it's too cumbersome to program I will not experiment and enjoy and use the options as much. I decided that if I go though all the trouble of building a HT oven it's a once in a lifetime thing and it has to be able to do all the things I might want from it.

PLEASE - NO LINKS TO SALES PAGES!. ... I just have to check the cycling time with the manufacturer. There's no complete specs available on their website.

S Stacey : for some reason the controllers you mentioned (the easy ones) are difficult to get without a complete oven.. (I can't even find out how much those controllers cost, which is usually not a great sign)
 
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Immediate thoughts: that one has effectively no manual. There's no mention of adjustment/tuning of the PID terms or any mention of an autotune facility. The input is type K only: I like to use Mineral Insulated type N thermocouples. Type N was developed specifically to address the "drift" issue that affects type K when used above about 1000 degC, 1832 degF. Drift is a progressive loss of accuracy with time-at-temperature.

I have always used industrial controllers for my HT ovens: Omega CN7823 or AutomationDirect Solo 4848VR. Same controller, different badges. I usually buy from whoever has the best price at the time. For many, Omega will have a slight advantage because they can supply the thermocouple as well. Auber look good, but don't have a UK presence. This ruled them out for me.

I settled on the Omega/AD controller after building my first HT oven back in 2009 to a set of online plans, hooking it up to a bunch of thermocouples and a datalogger (borrowed from work), and finding out just how poorly a basic controller, set up with autotune and default output cycle time, controlled the process. Ramping to setpoint and running a short cycle time makes a huge difference.

It is worth sitting down with a cup of coffee, a notepad and the phone, and talking to the technical sales folk at Omega Instruments. They are obviously there to sell you stuff, but Omega sell pretty much everything related to temperature control and IME they'll tend to point you towards what works well, rather than just what they have available. They tend to know their subject and they tend to be patient.

TBH, the thing that most impressed me with Omega (UK) was "I'm not entirely sure. My colleague who specializes in that is at lunch. Please can I take your number so he can call you back?" followed by a call half-an-hour later from someone who was clearly very-well-clued-up and could answer my highly technical question. No BS, no hard sell.

My recommendation for a basic controller is just because it's less complicated. Think in terms of learning to drive an automatic vs a manual. If you are going to build a successful HT oven, there's a good chance you'll want to build a dedicated tempering oven later. This can use the basic controller after you've upgraded the HT oven to Ramp/Soak. There are many other uses for a PID controller and it's unlikely to be wasted money.

As an aside, I put a 240V LED indicator on the control panel, wired in parallel with the coil feed. On a 2-second output cycle, you can get a pretty accurate idea of how hard the elements are being driven from across the shop. I find it useful.
 
Yeah, you are right! No manual :(. And no specs even. I am considering Omega and Auber. It seems to me there are no good smart PID controllers that are user friendly.. These are my future plans so I have plenty of time to search some more. Thanks for your help Tim! I appreciate...
 
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