PID controller hook up help please

Discussion in 'Fridge/Freezer Builds' started by ryans01z28, Apr 5, 2013.

  1. ryans01z28

    ryans01z28 Fire Starter

    that is correct
  2. dward51

    dward51 Master of the Pit OTBS Member

    Ok, lets take this in stages....

    First we want to get the PID powered and hooked to the SSR and RTD temperature probe.  We will add the load (heating element) side of the circuit after we get this first part working properly.

    DOUBLE CHECK that your terminals on the back of your PID are numbered like the ones in my diagram.  If they are not, let me know and I'll redo the diagram.

    • Take the female end of the extension cord off and set it aside for now. We will not be using it until after we get the rest of the controller working.
    • Note I changed the color coding on this diagram to make each wire distinct.  You can use any color you want, but using different color wires makes it much easier to see what is actually hooked where at a glance.
    • Hook the black and white 115v AC wires from your extension cord (the part that plugs into the wall) to terminals #1 & #2 on the PID.  It does not matter which order they go in as it is AC power.
    • Hook up a wire from terminal #3 on the PID to terminal #4 on the SSR. Then hook up a wire from terminal #4 on the PID to terminal #3 on the SSR.  These wires are carrying the low voltage DC control/triggering signal from the PID to the SSR.  This low voltage signal is what activates the "switch" circuitry inside the SSR.  There is *NO* 115v AC carried on these wires and the PID does not provide any AC power to the SSR.
    • Hook up a jumper wire from terminal #7 to terminal #10 on the PID.  Hook up a 2nd jumper wire from terminal #8 to terminal #9 on the PID.  Then hook the 2 wires from the RTD sensor to terminals #7 and #9 on the PID.
    • Don't hook up anything else right now (and Yes, I know it will not power the heating element "as is" but we need to do this in two stages as you are confusing the wiring so I'm trying to keep it straight forward).
    Once you get it wired like this, plug the 115v extension cord into the wall outlet.  The PID should come on and go through the self test.  Re-test your temp probe in ice water like before and it should be very close.  If not try reversing the two wires from the RTD sensor (swap the RTD wire from terminal #7 on the PID to terminal #9, etc....).  It should be working at this point.

    Try setting a higher "set point" in the PID (desired temperature) and the red LED on the SSR should come on as should the "output" LED on the front of the PID (just above the set buttons). Change the "set point" in the PID to below what the current temp reading is and both of those LED lights should go off.  If you get this far, then this first part if working properly.

    Give me a few minutes to draw the rest of the setup and I'll post it.  If you get this done before I post part 2, let me know if part 1 is working or not.  DO NOT wire part 2 until you get part 1 working properly.

  3. ryans01z28

    ryans01z28 Fire Starter

    Now that looks like a diagram I can follow lol. I will get it hooked up in a little bit I'm driving to my other house right now
  4. dward51

    dward51 Master of the Pit OTBS Member

    Ok,  here is part 2 where we add the 115v power that will run the heater.  Don't add this part until you have the first part working (red LED's on the PID and the SSR go on and off as the temp changes indicating the SSR is being switched properly by the PID according to temps).
    • Make sure the extension cord is unplugged from the wall before starting this part.
    • Take the black wire from the female pigtail (cut female end of the extension cord) and attach it to terminal #1 on the SSR.
    • Take the white wire from the female pigtail and attach it to terminal #2 on the PID (should be the same terminal the other white wire is on).
    • Take a new black wire and attach it to terminal #2 on the SSR. Attach the other end of this new wire to terminal #1 on the PID. This black wire needs to be the same thickness (gauge) as the wires in the extension cord.
    What this does is wire the pigtail in parallel with the 115v AC power coming into the PID except for a split between terminals #1 & #2 on the SSR (this is where the power is actually switched - between these two terminals on the inside of the SSR).  Try and visualize a switch inside the SSR between terminals #1 and #2.  There is no electrical connection between that side of the SSR and the low voltage triggering side (it's an optically isolated circuit and unlike a relay has no moving parts).

    You should be able to plug a table lamp into the end of the extension cord and the light will be turned on and off depending on the PID "set point" and temperature the RTD sensor is reading.

    Just make sure when you build the final version to reconnect all the ground wires and there should also be a ground wire run to the metal cabinet and box housing the electronics (you can use a wire nut to connect them on one end and the cabinet ground end should be screwed down solid).  I would also add a resettable breaker or fuse to the final circuit.  It would be best to add a terminal strip for power distribution before both the SSR and PID and fuse each of them separately (low amperage to protect the PID and up to the rating of your wiring for the SSR side).

    Let me know if this works.  It will probably be tomorrow night before I'm back online as I have a 800 question test for a new job I'm in the final running for.  My brain may be fried by then anyway.....

    Last edited: Apr 8, 2013
    dirtsailor2003 likes this.
  5. dcarch

    dcarch Smoking Fanatic

    When I got my first PID controller (similar to the one shown), I spent days of frustration trying to make it work, as it turned out it was a faulty unit. 

  6. dward51

    dward51 Master of the Pit OTBS Member

    I just thought of one more thing you did not bring up earlier.

    Did you buy a heat sink for that SSR?  You will need one for the final build if you did not (and bigger is better).  I would not try to hook up the heating element even for testing without one, but a low wattage table lamp should be fine for testing.
  7. dward51

    dward51 Master of the Pit OTBS Member

    It's all from China, so there is always the failure factor potential.  I think his is OK as in his first set of photos he had the PID switching the SSR properly.  The AC side was not doing anything though.  That and the jumpers were missing from the 2 wire RTD he has.
  8. geerock

    geerock Master of the Pit SMF Premier Member

    I know you guys are close on this but for about 120 or so bucks you can get a true plug and play pid from auberins with auto tune and six stage programming where you simply plug your cooker in the outlet in the back of the controller. You might, MIGHT, have to put a jumper in to bypass the existing controller. Thats it.
    Last edited: Apr 8, 2013
  9. ryans01z28

    ryans01z28 Fire Starter

    ok here's what I get now when I  plug it in now.  the temp is way off. does the wiring look to be correct?
  10. dward51

    dward51 Master of the Pit OTBS Member

    To me the photos of the wiring look ok.  However that 1017 degree temp reading is way off like you said.  And your LED's on the PID are not lit correctly.  I think the PID might have been damaged in one of the earlier wiring setups you did (that 2nd set of photos you posted was way wrong).

    In your newest photos It looks like the "out2/alarm 2" LED on the PID is lit, but it should not be as your factory configuration was for a single output PID.  Also your alarm 1 LED is lit, but since your process value is reading so high I would assume you have exceeded the default alarm set point in the configuration so that may not mean much.   Another possiblity is the RTD is bad (remember it has never read correctly) but we are also taking a 2 wire RTD into a 4 wire RTD device.  I would have gone the J type thermocouple route which is a simple 2 wire hookup and the leads are marked for polarity.   I've never tried to hook a 2 wire RTD into a 4 wire PID before but there is a lot of material out there on this.

    Dial the set point value (desired temp value) to above 1017 and see of the red LED on the SSR comes on.  It should.  If it does, then we just need to figure out what's up with that 1017 degree reading and it may be the RTD sensor.

    Do you have a VOM available?  You may need to test some of your components to make sure they did not get fried earlier.  It is also not unheard of for ebay items from China to be bad as shipped.
    Last edited: Apr 10, 2013
  11. dcarch

    dcarch Smoking Fanatic


    However, an eBay PID is less than $20, which make it very attractive to have a back up unit.

    If you have a $200.00 worth of meat planned for a big  important weekend party, you better have a back up unit.

  12. geerock

    geerock Master of the Pit SMF Premier Member

    True also.....

    except I had one that looks exactly like what our friends in the previous posts are playing with and it lasted thru one and a half smokes.  Bought another one and it was defective out of the box.  And with the trouble these two are having with this one....... well... I rest my case.  Maybe I just had bad luck with the ebay ones, but the 2 auber units and one auber clone I have (one on an old Bradley, one on a MES 40, and one on a homemade smoke house) are dead solid on with temps and programming for quite some time now.   
  13. ryans01z28

    ryans01z28 Fire Starter

    when I set the temp higher than than the reading the ssr light does not come on

    I have a vom in my electrical bag yes
    Last edited: Apr 10, 2013
  14. dward51

    dward51 Master of the Pit OTBS Member

    From your last photo the "output1" LED on the PID did come on when you raised the set value.  That is good.  Did you try and reverse the leads on the RTD sensor?

    Since we know at one time it was wired with AC power on terminals that should not be wired into AC power the components may be damaged.  Time to do some trouble shooting on individual components.  If one or more of them is fried, then all the rewiring in the world will not make it work.

    With the PID & SSR "as is" I would test the DC output from the PID. With the set value set high like your last photo, it should be triggering the SSR but the SSR LED is not on. Measure the DC voltage across the SSR output terminals on the PID (terminals 3 & 4 on the PID). You should get a DC voltage there.  If you do, try swapping the wire leads on those terminals to reverse the polarity going to the SSR from the PID and see if the SSR's LED comes on with a high set value then.  If you get no DC voltage out of the PID when the output1 LED on the front of the PID is lit, it's fried.

    Next I would test the SSR (unless it works after you reverse the DC triggering leads in the step above - if it works, leave it alone). Unhook everything from the SSR and then take power from either a low voltage DC power supply or the power from a 9v battery and see if the red LED on the SSR will come on when power is applied to terminals #3 & #4 on the SSR.  Then hook your VOM up to terminals #1 & #2 on the SSR and see if you have continuity when DC power is applied to terminals #3 & #4 (remember there is a "switch" inside the SSR between terminals 1 & 2 and it should close when DC triggering signal is present on terminals #3 and #4 and the LED should also light).  If you do, then the SSR is still good.

    Next I would pull the RTD sensor and measure the resistance across those two leads.  A RTD100 sensor should read 100 ohms resistance at 32*F (ice water bath).  Try that to make sure the RTD is good also.
    Last edited: Apr 10, 2013
  15. ryans01z28

    ryans01z28 Fire Starter

    ok I reversed the LEDs at the pid and the light came on on the ssr.
    The rtd was at 101.7
    Last edited: Apr 11, 2013
  16. dward51

    dward51 Master of the Pit OTBS Member

    So the RTD is reading 101.7 ohms in an ice water bath.  Sounds like it's good.  And you reversed the leads from the PID to the SSR and the SSR is now being switched by the PID like it should.

    Double check the internal configuration of the PID to make sure there is not some weird value programmed in (although off the top of my head, I don't know what value could make it read 950* off like that.  That process temp "should" be beyond the range of a RTD sensor anyway).  I'm thinking you have a bad PID.  It is not unheard of for those China models to be bad out of the box.

    Anybody else got any suggestions?
  17. ryans01z28

    ryans01z28 Fire Starter

    i don't know how to check to see if something is programmed wrong on the pid either sorry. I know I'm not much help on this project and I didn't think it was going to be this big of a headache. All I wanted was to have some control over my heat. Is there a way to test the pid? I have an extra ssr but no extra pid
  18. ryans01z28

    ryans01z28 Fire Starter

    When the temp on the pid is reading 1035ish and I set my temp to 1020 and grab the probe it rises like it should. I set the probe in ice water and when the temp drops down to 1020 it will turn a lamp I have pluged in ON and If I take it out of the water it turns it OFF like it should. We just need to figure out how to calibrate it or something.
  19. ryans01z28

    ryans01z28 Fire Starter

    heres some pics for you
  20. dward51

    dward51 Master of the Pit OTBS Member

    Run the power up self test on the PID.

    Unplug the PID from the wall outlet and then plug it back in watching the display. You should see the following:

    This next one is the one I'm most interested in now.  The current input type may be set wrong. It will be the bottom value on this display.  If it is a "Y" (which is really a K) it is wrong.  We need it to be a "Pt"

    This is what you want it to be showing "Pt" which is for a RTD 100 type sensor.

    The the last screen will be this before it exits the self test and goes to normal operation.

    I suspect your input type is set wrong and the PID is trying to read the input from the RTD sensor as a K type thermocouple which works on a totally different method.  If your input does not show "Pt" on that part of the self test upon power up, you will need to change it. I believe the factory default setting is for a K type thermocouple and if you have not previously changed this in the setup, it will not read correctly (which appears to be what the current problem is).

    Here is how to change that setting (and any of the other settings, but just deal with one thing at a time).

    The input type parameter is the 6th setting in the configuration menu, so you will need to step through the other options first. 
    1. Press and hold the "SET" button on the PID for more than 3 seconds.  The display should change to show the setting field name in red and the value currently set in green portion of the display.
    2. Press "SET" again to move forward to the next setting field.  Do this until the red part of the display shows either *F or *C.  If the green part of the display *DOES NOT* show "Pt" then you must change that value.
    3. Press the "AT" button to change the value
    4. Then the "up arrow" or "down arrow" button to change the green displayed value until it shows "Pt".
    5. Press "SET" to save the new value (should still show "Pt").
    6. Press and hold the "SET" button for more than 3 seconds to exit the setup menu.
    Unplug and replug the PID into the 115V power outlet and verify the setting was saved as it steps through the self test display again.  You should see the "Pt" setting this time.

    Let us know how this goes and if it fixes the temp reading issue.
    Last edited: Apr 11, 2013

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