Simple PID setup/how-to

[AnthonyUK]

Any tips for calibrating in that range?

[darkonnis]

we calibrated a very expensive platinum rod against a very expensive mercury thermometer by simply going down 2c at a time from 100 to 0. I'd suggest you get as many thermometers as you can and stick them in a pot of water thats about 60c, you'll know its 60c because the majority will register 60, chuck your PID in there and see if it registers 60. It might not, if it doesn't record the difference so you can manually correct it on brewday. then simply go up in 1 or 2c stages by adding a bit of boiling water. and letting it mix and settle. rinse repeat up until your max sparge temp + a few degrees and you're sorted

[subfaction]

Hi guys,

I've just upgraded my buffalo with another 2.4kw element, and now want to upgrade my control box to run x2 SSR's to control both elements using the same PID.
I'm clear on the wiring for this, BUT I've also got a couple of 3 pin 12v illuminated switches I was going to wire in the PID relay circuit, so I can switch the elements on and off independently any issue in doing this?

[Fil]

Yes, but there are a couple of things to consider

if u want to turn on an element independently of pid control, u will need to supply a dcv current to switch the ssr on.

secondly the ssrs can leak or bleed the load when off, i encountered this after fitting a neon indicator on the live load. with the pid off the neon flickered and on checking with my hand the element was warm to the touch..

It may be simpler and work closer to expecvtations to get hi amp 240v ac switches to allow you to isolate and overide the ssrs.

[subfaction]

Thanks Fil, I did this last night and just now cooling a weizenbock, the switches worked nicely. And now it's cooling have turned off the sockets to ensure there's no power bleed as you describe. In hindsight i'd have been better getting 240v switches, that's for next upgrade!

[themadhippy]

if u want to turn on an element independently of pid control, u will need to supply a dcv current to switch the ssr on.

or wire a dpdt center off switch on the mains voltage side,this will give you on-off-pid control