Pid Newbie Stuff

[bignath]

Hi all... Have done a quick search but I don't understand all the PID stuff.

Currently I am using an STC1000 to power a power board that runs a 2200w kettle element and little brown pump. Stc powers up board and element and pump are then on simultaneously.

I would like to limit the over and under shooting of the st by using a PID instead.
Where do I start with this plan? Is it just a matter of swapping out controllers? I am comfortable with wiring stc's (done 3 myself). What do I need, how does it all go together, and how does it all work??

Lay mans terms where possible please. I am really uneducated in this sort of stuff...

Cheers,
BN.

 

[mxd]

swap the stc with a pid, change the temp probe from STC to a good one that the pid handles.

Set the pid up for the probe,

then tune the pid (the pid should have an autotune function)

To tune the pid it's "best" ?(i.e my opinion) to do tune whilst doing a "standard" (by that I mean my standard brew e.g. 5 kg of grain, 20 ltrs of water 55 Degrees) mash.

The autotune will set the pid values that will allow the pid to know your system under the above scenario to hit and keep the temps required.

 

[dicko]

Big Nath

Have a look at this off Brew Adelaide.
I have not gone any further with mine at the moment due to not wanting to pull my current control box apart while I am trying to brew before Xmas but there is plenty of basic info on Pids

http://brewadelaide.com/forum/index.php?topic=855.0

Cheers

 

[squirt in the turns]

Assuming this is for your recirculating BIAB rig? Why wouldn't you want to recirculate constantly, and only switch the element on and off as required (pump stays on)? I don't know much about these single vessel builds that are becoming so fashionable, but that's how it's done with RIMS/HERMS.

As mxd says, it's a reasonably straight swap, except that unlike the STC-1000, the PID does not have a 240 volt, 10 amp relay built in. It has a 12 V output designed to switch a solid-state relay (SSR), which you'll need to get too. Get a PID like this Sestos one from eBay or this one from Auber. The eBay option is a kit that includes the SSR and a K type probe, but I'd definitely recommend getting a better probe. RTD type ones are best. Auber also sell these fully sick watertight stainless ones with a built in threaded fitting (no need for a thermowell). They come with a detachable cable which is super convenient and there's a "deluxe" option which gets you a stainless steel braided cable for extra durability.

I've got 2 of the Sestos PIDs and I upgraded my probes to ones from Auber. All works perfectly. The instruction manual is a bit incomprehensible and the settings a bit fiddly, but you'll only need to dick around with it extensively a couple of times while you're tuning it and setting the probe type. I think the dedicated HERMS and RIMS threads have some good info, and plenty of folk on here such as wolfy and myself have the Sestos controllers (the Aubers are popular too), so if you get stuck you'll be able to get specific help.

DO NOT forget to put a heat sink on the SSR, otherwise it will burn out.

 

[raven19]

I have a bit more background on PID's in my brweery build in my sig below too, aliong with others on AHB that have used PID's in recent times.

 

[bignath]

Squirt...

Yep it's for the single vessel. The only reason I don't run pump constantly is due to losing too much heat. Therefore I have to run the element more often than I want to. So my workaround has been to only run pump and element together when required.

Cheers for links, I'll check it all out.

Hypothetically, if you can wire a stc, will I be able to put this together myself?

 

[booargy]

They are not that much more complicated. The PID has a low voltage output to power the SSR. So the power to the element from the STC gets moved to the SSR. The SSR is then powered by the low voltage output from the PID. I reckon you'll be able to do it and there are plenty of people here to help IF you get stuck.

 

[bignath]

Been researching PID all day so it seems....

OK, do i have this right?

Power is supplied to the PID which you set at whatever temp you want.
An SSR is connected to the PID and when the probe registers deviation from the set point within the parameters set by the user, the PID sends a signal (voltage??) to the SSR, the SSR then converts it to 240V, give or take, to be used to connect an element.

The SSR connects to the PID, and the element connects to the SSR?

Assuming i have that right, how much better are the rtd pt100 probes, compared to the "k" type?

I have to admit, the whole all in one bundle (minus heatsink) looks pretty appealing at less than $50 shipped.

As an example:

http://www.ebay.com.au/itm/Digital-PID-Tem...=item33707c59d8

Oh, and one other question...

If the power is going to the ssr from the pid, the ssr only has two terminals in, and two terminals out, so does that mean it doesn't need an earth? Or am i incorrect in assuming that one terminal in and out is active and the other in and out is neutral...

 

[browndog]

Been researching PID all day so it seems....

OK, do i have this right?

Power is supplied to the PID which you set at whatever temp you want.
An SSR is connected to the PID and when the probe registers deviation from the set point within the parameters set by the user, the PID sends a signal (voltage??) to the SSR, the SSR then converts it to 240V, give or take, to be used to connect an element.

The SSR connects to the PID, and the element connects to the SSR?

Assuming i have that right, how much better are the rtd pt100 probes, compared to the "k" type?

I have to admit, the whole all in one bundle (minus heatsink) looks pretty appealing at less than $50 shipped.

As an example:

http://www.ebay.com.au/itm/Digital-PID-Tem...=item33707c59d8

Oh, and one other question...

If the power is going to the ssr from the pid, the ssr only has two terminals in, and two terminals out, so does that mean it doesn't need an earth? Or am i incorrect in assuming that one terminal in and out is active and the other in and out is neutral...

The SSR doen't really do any converting as such, it is simply a switch for the 240V that the PID pulses on and off.

 

[labels]

Regarding PID (slghtly OT) I replaced one on our hot foiling unit on our label press at work with exactly the same type as you are talking about with a K type probe.

It ramps quickly to within 10C of the target temperature before it slows down and creeps slowly, then holds exactly spot on for eight hours at a time very occasionally drifting down 1 degree for only a second or so.

We manually tuned this device for our needs but please DON'T ask me how, it was bloody complicated.

Steve

 

[bignath]

The SSR doen't really do any converting as such, it is simply a switch for the 240V that the PID pulses on and off.

Ahhh, ok BD.

everything else i assumed is ok though?

 

[Adam Howard]

An SSR is a powered switch basically, it is wired inline with 240V and the element. The PID is able to flick the switch on and off REALLY fast to maintain a temp.

 

[bignath]

right.

so would the "crude" signal flow basically go:

240V in -> PID -> lower voltage -> SSR (solid state relay/PID controlled switch for want of a better term) -> 240V -> ELEMENT??

 

[browndog]

Ahhh, ok BD.

everything else i assumed is ok though?

Can't really comment on the probe types, but the one advertised with the unit on the link will do the job. As far as wiring goes, you need to supply the PID unit with 240V to power it, it outputs low voltage to the SSR to cause it to open and close. You run the active to the element through the PID and neutral and earth direct to your element. The SSR switches the active to the element on and off according to the PIDs output.

The diagram on the SSR pretty well explains what it does.

 

[bignath]

Can't really comment on the probe types, but the one advertised with the unit on the link will do the job. As far as wiring goes, you need to supply the PID unit with 240V to power it, it outputs low voltage to the SSR to cause it to open and close. You run the active to the element through the PID and neutral and earth direct to your element. The SSR switches the active to the element on and off according to the PIDs output.

The diagram on the SSR pretty well explains what it does.

So are you saying that the only wire going into and out of the ssr is the active?

I know it probably comes across that i'm an electrical liability, but if i can sort out in my head how to use the ssr, then i am confident i'll have a lightbulb moment, and all will be sweet.

As previously posted, i've successfully easily assembled several temp controllers for my keezer, ferm fridge, and current controller on my single vessel rig....i've installed several sets of spotlights on my trucks, car stereos etc..I know 240v shouldn't be ****** with, but if i can get it through my head in a diagram of sorts of how to get from PID, to relay, to elemet, i'll be fine....

 

[browndog]

So are you saying that the only wire going into and out of the ssr is the active?

I know it probably comes across that i'm an electrical liability, but if i can sort out in my head how to use the ssr, then i am confident i'll have a lightbulb moment, and all will be sweet.

As previously posted, i've successfully easily assembled several temp controllers for my keezer, ferm fridge, and current controller on my single vessel rig....i've installed several sets of spotlights on my trucks, car stereos etc..I know 240v shouldn't be ****** with, but if i can get it through my head in a diagram of sorts of how to get from PID, to relay, to elemet, i'll be fine....

yep, thats right, if you can just imagine the SSR is a switch that cuts the active to the element you will have it. With the temp controllers you have wired up, they have a relay inside them that switches the active on and off. With a PID/SSR it basically does the same thing but the SSR can handle more current and switch a lot faster than the relay inside your temp controller. So you are looking at active and neutral into your PID, + and - out of the PID to the SSR. Then another active to the SSR and from the other side of the SSR to the element and a neutral and earth going to your element. Clear as mud?

 

[bignath]

yep, thats right, if you can just imagine the SSR is a switch that cuts the active to the element you will have it. With the temp controllers you have wired up, they have a relay inside them that switches the active on and off. With a PID/SSR it basically does the same thing but the SSR can handle more current and switch a lot faster than the relay inside your temp controller. So you are looking at active and neutral into your PID, + and - out of the PID to the SSR. Then another active to the SSR and from the other side of the SSR to the element and a neutral and earth going to your element. Clear as mud?

hmmm right.

gotta go cook tea for me and mrs nath....give me a little while and i'll no doubt be back after i let all that sink in....

 

[twizt1d]

having set up a PID controlled RIMS system not that long ago myself i can give a bit of advice in saying dont make assumptions when it comes to wiring this stuff up, if you arent 100% confident of what you are doing then get a sparky or someone that knows what they are doing to wire it for you.

 

[bignath]

having set up a PID controlled RIMS system not that long ago myself i can give a bit of advice in saying dont make assumptions when it comes to wiring this stuff up, if you arent 100% confident of what you are doing then get a sparky or someone that knows what they are doing to wire it for you.

cheers mate, i know i'll be 100% confident if i can just make the loose ends in my head join up.

Am starting to think that the stc was one thing, but the pid seems different altogether, just need to make the "different connection" in my brain.

Not planning on screwing around if i don't fully understand what i'm getting into.
For me, it FEELS like a simple job to wire one up, i just need it to make sense to me. If it doesn't make complete sense, rest assured, i won't try it.

 

[booargy]

The STC-1000 switches the element with a relay. This relay is internal.
*a mechanical relay is a set of contacts connected to to an electromagnet. when the magnet is energized it pulls the contacts together allowing electricity to flow)
On a PID this relay is external so the unit puts out a low voltage to power the solid state relay
*A Solid State Relay doesn't have contacts or a magnet but it still uses voltage to energize it which allows electricity to flow.