PID to SSR wiring - help needed please!!

[uksmoker]

Please help!!!

I've been making a temperature controller in a project box - but I just can't get the PID to operate the SSR.  The good news is that:

1. I've read all the helpful threads about PID/SSR wiring on SMF, and I'm 99% sure that the 240V circuits (UK mains voltage) are OK
2. The SSR switches the load (a 1500W electric hob) on and off when I apply/remove a 12V DC feed from a transformer to its input terminals (nos. 3 and 4).  The SSR's output is rated 24-380V AC, which seems to be fine
3. The thermocouple temperature probe works fine, giving an accurate reading on the PID
4. The PID itself seems to be working OK in response to the target and actual temperatures, with the "OUT1" indicator light switching on and off as the temperature homes in on the target, and regular clicking noises which I guess is the output circuit being opened/closed (?)

The bad news is that:

1. I'm still not sure that I understand the output terminals from the PID.  The instructions are (you know what's coming next don't you...!) really hard to decipher and seem to have errors in them
2. The outputs I have measured from the output terminals of the PID seem to be very low - less than 1 volt DC (the PID is rated 3-32V DC on the input side, so this wouldn't be enough I guess)
3. The PID instructions say "Relay contact output: 250V AC, 3A (Resistive load)".  I'm not sure if this means the output from the PID or from the SSR that the PID controls - but if it's from the PID then I could be in trouble!  But I tested for a high voltage AC output from (what I think are) the PID output terminals and didn't pick up any reading.

I'm wondering if maybe I am wiring up the wrong outputs, or maybe I've just bought a PID that doesn't match the SSR?  Or is it a faulty PID?  If anyone could help me here, I'd be really grateful because in the meantime all my smoking is based on manual readings which is a pain.

Background info:

The PID is this one:

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=150655770257&ssPageName=ADME:L:OC:GB:1123

...and here are the "instructions".  My model is highlighted - it's the CD701.  There's some typos in it - the input terminals described (10/11/12) don't point to the matching terminals on the diagram - though I found that 17 and 18 work fine.  BTW I don't understand which SSR connector should go to 4, 5 or 6, but I have tried all 6 combinations without any luck (as described above).

The SSR is a Fotek SSR-25 DA:

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=350500401778&ssPageName=ADME:L:OC:GB:1123

Sorry if this is the longest post ever but I wanted to provide as much information as possible in one go.

Thanks for any help you can give!

UK Smoker

 

[daveomak]

UK Smoker, morning... I don't have a clue..... I'm bumping this so it will stay in the loop......  Dave

 

[BGKYSmoker]

I built a PID a few years ago.

Follow this link for wiring .

http://www.susanminor.org/forums/showthread.php?315-PID-Controller

 

[kevinscorral]

To operate an SSR with that PID, you need to have the Triac enabled version.  Refer to page 1 of the users manual for the model code.  A triac enabled PID will have a model code something like CD701 XXXX-T*XX-XX.  If there is an "M" in place of the "T" in your model code, then you have a relay version.  The relay version will not work with a Solid State Relay.

Hope this helps.

Kevin

 

[sprky]

I built a PID a few years ago.

Follow this link for wiring .

http://www.susanminor.org/forums/showthread.php?315-PID-Controller

                   

  I'm thinking this will help you out 

 

[uksmoker]

Thanks nepas and sprky for pointing me to that excellent article on wiring!  I've checked it out and it confirms that all my wiring is OK, so it's good to know that that's not the problem.

Thanks also kevinscorral.  Yep - it turns out my PID has an "M" in it - FK01-M*AN-NN ZK-1033.  So does this model have a relay built into it?  If so, could I just wire my live cable through the back of the PID and let the PID do the switching?  Having said that - if the output rating is 250V AC at 3A resistive load, would it cope with a 1500W hob?

Really appreciate the help and support I am getting here!

UKSmoker

EDIT

I've just checked the instructions for my PID and they do mention "Trigger output (for triac driving): Zero cross method for medium capcity triac driving (100 A or less).  Triac output: 0.5A"  This might as well be written in Chinese AFAIC but you can see this on the scan of the instructions above - towards the bottom right corner.  Does this mean that my PID has got the right triad capabilities (whatever they are)?  If so, how should I wire it up?  Thanks!

 

[kevinscorral]

It does not mean that it has a relay built in, just that it can drive a mechanical relay at 250VAC, and up to 3A current draw.  This will not drive your heating element.

The trigger output (again, not enabled on your unit because it is the "relay output" model) would be used to drive a seperate triac circuit.

The bottom line is that the PID you bought will not work with an SSR.  It is intended to be used with an electromechanical relay.

Kevin

 

[uksmoker]

Thanks Kevin - that's really helpful.  Saved me even more hours of head scratching!

Presumably I just need to buy a replacement from eBay that states "SSR control" for the output.

Thanks again

UKSmoker

 

[uksmoker]

Update:

I've just ordered one of these, which I hope will work OK

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=230727736436&ssPageName=ADME:L:OC:GB:1123

Specifications

Display Type	Dual RED & GREEN DIGITS LED Displays
Power Source	85V~260VAC / 85V~360VDC (<2w)
Measuring Range	-200oC ~ 2300oC (Nominal)
Sensor Input	T,R,J,B,S,K,E,WRe3-25,Cu50,Pt100
Accuracy	0.2% FS
Control Mode	PID, On-Off, Manual, and Limit
Output Mode	SSR Driving Output, 8V (40mA)
Alarm Output	High & Low Alarm Relay Outputs
Panel Cutout Size	45 mm x 45 mm
Dimensions	48mm (W) x 48mm (H) x 81.5mm(D)

Ideal for use with

l Uses in Swimming Pool, Aquarium, Refrigerator, Chiller, Furnace, Heating, Cook Device, Various Test and Industrial Equipment...etc.

Features

l High Quality! Good Performance! Easy to install and operate!

l 1/16 DIN that is only 48 x 48 x 81.5mm size

l Can be powered by either DC or AC power source

l Dual ultra-bright RED & GREEN digits LED display for both set temperature and process temperature

l Artificial intelligence enhanced PID algorithm for accurate and stable temperature control

l Auto-tune function can find the best PID parameter automatically.

l On/off control mode for refrigerator, motor and solenoid gas valve.

l Bump less transfer between Auto and Manual control

l Limit control mode for safety protection and special applications

l The PID, on/off, or limit control output can be configured by user for either relay contactor or SSR control

l Two contact relays can be configured as one PID and one alarm output, or dual alarm outputs.

l This instrument can display ºC or ºF

l Four digits LED display can go up to "9999"

l Support 10 different types of commonly used temperature sensor inputs.[ RTD input (Cu50, Pt100) or thermocouple input (T, R, J, B, S, K, E and Wre-Wre25) ]

l Type-K Thermocouple (Length=2 meters; up to 800ºC) included

l All item are 100% Brand New & Fully Checking is work before shipping.

 

[kevinscorral]

There you go, that'll work.

Glad I could help.

I am an Electrical Engineer, and I built a PID controller for my Smokin-it smoker.  With the mechanical thermostat that came with the smoker, I was seeing temperature fluctuations up to 50deg F.  With the PID controller handling things, I can keep the temperature within a degree or two of the set value.  Also, I can now run the smoker at higher temperatures for birdie cooking.  PID's are great, and should come with every electric smoker, in my humble opinion.

Kevin

 

[cooker98]

looks like your wiring is correct. I use pids quit often and have used the one you had at first. I don't rem. off the top of my head but I think the issue u were having was a programing issue. most pids come with a default setting of the output being pid controlled. this means that the output voltage is directly propotional to the amount of degrees the set temp is from the actual thermocoupler reading. if you set the pid to on/off control this will cause the pid to act like a switch and switch on and off when the desired temp is reached. now if you r using ac to control your relay it is sometimes not necessary to do this because there is no voltage drop on a ac controlled circuit. also u have to set the pid to heat loop on off and not a ramp up settjng. but most I've seen come preset to a heat setting. 90% of the time the problem is in the parameters of the pid and not the pid itself. hope this helps.

 

[dsiewert]

Looks like you are past this point, but I just stumbled upon your queries.  In your original post, it seems like your pid output was AC but your SSR input was expecting DC.  Fotek makes other variations in their SSR which  take AC input.  Another approach would have been to put a full-wave rectifier (or maybe, even a half-wave might work) to convert the AC output of the pid to a DC input for the SSR. 

Hope everything works out.

 

[starrider63]

 I checked the links a couple member posted about PID programming and wiring. Those links no longer exist. I wired a Inkbird Brand Temperature Controller to a Heating element a couplke years agot to heat water in a Small Hydrographic Dip tank. I am now building a Larger Dp Tank that requires 2, 240 volt 5500 watt Heating Elements. I do better with Visuals along with written instructions. If anyone knows of a Schematic to wire a PID or Inkbird Brand Controller( I'm not sure what TYPE of COntroller the INKBird Brand is but, it has less connections on the back and is easier to program.) But,I have a PID Contoller still here. So if anyone knows of a Schematic to show how to wire a Controller through the SSR to a Solid Ciontact to actually put power to the 2 heating elements, Please, please let me know. I don't have a lot of hair left anyway, can't afford to pull more out. Thanks guys.