Pid Calibration - Trust The Probe Or Calibrate It?

[bignath]

Just a quick question for those PID owners out there.

I am (with a bit of luck on the postie side of things) about to receive my auberins pid and rtd pt100 probe in the next week or so.

I've been reading up on how to calibrate, but i'm interested in whether everybody calibrates their pids/probes, or are they generally accurate "out of the box'?

Im sure i know what most will say, but i'm interested in trying to get some idea on how accurate they are (or are not) out of the box in your opinions.

Assuming you all say, definitely need to calibrate them, the best method would be with a lab type thermo at mash temp? Or would you do the ice water, boiling water duo?

Cheers,

Nath

 

[geneabovill]

Mine (a Sestos cheapie) was about 3.5 degrees out when I bought it, but after autotuning, it fell into line. Not sure if that's a feature, or sheer luck, but that's my story.

I'd suggest you test it out anyway. You might be lucky, but best to have a successful brew rather than a beer that's too dry or, heaven forbid, too sweet.

 

[QldKev]

Def calibrate it, and do it at mash temp because that's the temp we are concerned about.

My pid (setos) and all my stc-1000's all needed corrections for the temp.

Most lab companies have alco filled glass thermometers which are normally accurate.

QldKev

 

[Wolfy]

Calibrate - mine was also several degrees out - and not just at freezing/boiling but at usual-mash temps as QldKev suggested.

 

[spog]

Def calibrate it, and do it at mash temp because that's the temp we are concerned about.

My pid (setos) and all my stc-1000's all needed corrections for the temp.

Most lab companies have alco filled glass thermometers which are normally accurate.

QldKev

reserecting on old? Thread here,but QldKev can you tell me (us,instead of PM ing you).how did you calibrate your Pid.
The reason I ask is I have a non ramp Pid ( being single temp set Pid).Which suits me as I have a brew in a pot setup and am happy with the system as a simple single infusion setup.
I have been pissing around with the electronic side of the setup for ages and finnally decided to pull my finger out.
Have been brewing using a dial thermometer on the keggle,and yep would'nt you know it as usual,hmm,perhaps I can add something to make the process easier !? ( have'nt we all heard that before). And then your on the dark side .
The Pid I have is a no name ,as per above single temp set,I think as used in a coffee machine.(though bought new).

Cheers....spog... Any/all experiences/knowledge ideas welcome .

 

[Glot]

If it has a PT100 sensor then don't do freezing water and boiling water. Do a few comparison temps in between. This method will be good enough for what you are using it for.

 

[Glot]

A side note sort of. If you want to test it at 100 deg C then sticking it in boiling water won't tell you much. You need pure water at sea level when the barometric pressure is 1000 and then hold it immediately above the water in the steam. Not the water and not the water vapour. The invisible bit in between. But then again, how accurate do you want it? You are more likely to get your inaccuracies from the method of test. Even bubbling water temperature variations in it.

 

[QldKev]

All I did to calibrate mine was get a stainless brewing thermometer from ebay and set all my stc's and pids against it, and decent glass one will do. So in the case of a mash tun I use 66c for my reference point, then measure it where you would normally. Recirculating systems with a heat exchanger (HERMS/RIMS) from the exit of the HX, or for a non re-circulating system the dead middle of the mash bed; which is I guess where the temperature probe will be, just ensure you are measuring at that same point. When I first got my stainless/glass thermometer I was still working at Bundy Sugar and I checked it against their lab calibrated thermometer and it was actually correct. I've got several stc's, 2 Sestos, an Auber programmable pid and Matho's controller, I found no set pattern for adjustments with my controllers. Some were ok from factory, but most needed changing. Like anything with our brewing after you have setup the system and drank a couple of beers from them, you may need to tweak the recipe to suit your specific systems and get your desired results.

 

[spog]

Got it. Thanks for the replies fellas, now I just have to sneak some time in to set it up. ...cheers...spog