Help with PID controlled smoker plans using UK voltages

[Guttersnipe]

HELP! Living in the UK & Needing help with a smoker cabinet conversion.

I’m currently using a Peetz smoker cabinet (http://www.the-old-smokehouse.co.uk/pro ... moker.html) with which I’m using the purpose make heating element (http://www.the-old-smokehouse.co.uk/pro ... okers.html)says 2000W, actually 2300W).

The cabinet works very satisfactorily, however the variable control (dimmer knob style) lacks the fine control I’d like & requires near constant attention.

I’d like to build a PID controller mod for my cabinet, however I’m at a bit of a loss as to how to safely wire the unit.

I’d like to keep the existing control unit in the loop (both to tune down the system & also (lets be honest) in case the new setup is a disaster.

I’ve done as much research as I can w.r.t parts etc, however I’m coming up blank on a wiring diagram/specs which uses UK 240V current (plenty of builds with US & European setup).

Q. -Can anyone help me out with plans for a similar rig they’ve made in the UK ?


These are the parts that have been suggested to me so far :

PID - http://www.amazon.co.uk/Sestos-Digital- ... controller

SSR - http://www.amazon.co.uk/Temperature-Con ... _diy_img_z


Thermocouple (K type) - http://www.amazon.co.uk/-100-1250C-Thre ... uple+probe

Project Box - http://www.amazon.co.uk/PART-PLASTIC-H2 ... lastic+box

Switches - http://www.amazon.co.uk/ILLUMINATED-LAR ... off+switch


Other things I need (suggestions welcome) –

Wiring (?) Not sure what I need before & after the SSR...

Connector block

q. Which additional fuses do I need to include ?

Q. - What else have I missed ?


Q. – would the setup also be suitable to use for a fan powered BBQ controller ? (similar to this -http://www.bbq-brethren.com/forum/showthread.php?t=117534) What would I need to do to convert setup, or would it be better to simply build a separate unit altogether ?


Ideally I’d like to get a second thermocouple to measure the internal meat temps too – would I need a second PID for this? & (getting WAYYY ahead of myself) connecting the lot via wireless network to a data logger/Windows controller. . so any advice which might change have an effect on the parts I need would also be valued.

Sorry, that’s a lot of questions, but I’d really appreciate any help/advice offered....

[wheels]

Hi Guttersnipe,

I've just noticed that nobody's tried to answer your question.

I guess that's 'cos people don't want to say what they think for fear it's wrong and someone has an accident.

Controlling the temperature in a smoker is very similar to controlling the coldness of a fridge and I think that a similar system could be used. I detailed setting up such a system here, with a full wiring diagram here. Whilst it doesn't give the exact wiring for the PID you wish to use, it may give you some idea of what you need to do.

For monitoring meat temperature, most people use something like this:

http://www.ebay.co.uk/itm/Maverick-ET-7 ... 0655372101

HTH

Phil

[Wunderdave]

I'm not sure what's so complicated about this

Wire your PID's control circuit to a solid state relay that's rated for 240V. Make sure that the PID can either handle 240 volts or step down the voltage using a power supply. Wire the relay to your heater or outlet where the heater plugs in.

The concept of wiring this controller is the same as wiring it for 110V power except the components are different.

Instead of fuses you may want to consider using a circuit breaker rated for 20A which is about where your heater will top out it sounds like.

[Wunderdave]

If you look up how to assemble a sous vide controller there's plenty of good diagrams available that show how this is done:

[Wunderdave]

You can use a PID to power a fan-controlled BBQ as well. You may want to tinker with the settings or configure it as a bang-bang controller without the PID control but the fan's input for heat is scalable and pretty linear so it works fine.

[wheels]

Thanks Wunderdave, I was hoping that my response would prompt someone to reply.


Phil

[Dibbs]

I built a fan control system for my Kamado BBQ this summer using an arduino microprocessor board and a little computer fan. I programmed the PID algorithm myself with on the arduino but a commercial PID controller will probably work. I was unnecessarily obsessive about temperature swings and ended up with a stupidly complicated algorithm (after burning a small mountain of charcoal) but really it worked perfectly adequately with a standard PID algorithm once you get it tuned right.

One piece of advice. Don't use too big a fan. When you blow a lot of air in the temperature can actually go down for a while until the coals get going more. This usually causes the PID to increase the fan speed right up to max and it ends up overshooting the target temperature massively. It worked much better if I limited the max speed of the fan or used a smaller one. A bigger fan's great for getting it up to pizza cooking temperatures and beyond though. I've even had a roaring flame coming right out of the top. That was quite impressive.

[JamesMB]

+1 on the basic PID and then link to heater via a relay - just make sure you get one rated for your heater. Homebrewers often use the STC-1000 in this manner which will happily supply 240V up to about 10A. The only difference is that you need to ensure the temp probe is suitable and you may choose not to have a cooling side.

For BBQ use the BBQ Guru is amazing, just be careful about the size of port you use as the chimney effect will draw air in when the temp controller isn't blowing the fan.

[Guttersnipe]

Big Thanks to all for the advice , I'll have to check the ratings on the gear I was looking at.

Two quickies :

1. Top idea re circuit breaker, much better way of doing it. Is the R (resistor) marked on the diagram the right location for this?

2. w.r.t the PID controlling/handling the 240V - I thought that it's primary purpose was sending the control (lower?) voltages to the SSR which stepped it up to the full current? I checked the Sestos : -'Output: Voltage 12V for SSR, SSR control ready to connect external Solid State Relay to handle High current applications'.

Have also been recommended this http://www.amazon.co.uk/AGPtek%C2%AE-Digital-Display-Temperature-Controller/dp/B005NGL4KG PID too. Any preferences ?

[Wunderdave]

I'm not an electrician but I would wire the circuit breaker in series between the hot power lead and the SSR.

You're right that the lower diagram has a resistor on it but that probably has to do with thermocouple signal noise. Most PID controllers have a "filter" function that should eliminate the need for this type of wiring, or have three signal leads or (infinite variations).

About your second question - the PID does in fact just control the SSR with the full high amp high volt (high watt) load going to the heater via the SSR.

However the PID also needs juice to run (not much, like half an amp at 110V). some of them are probably wired to run on 240 volts, some will run on 110VAC, some on 12VDC, it depends on your controller's specs.