Cajun Injector XL PID Build

Discussion in 'Smoker Builds' started by jmabrao, Nov 24, 2015.

  1. jmabrao

    jmabrao Newbie

    Hey guys, a while back I got a Cajun Injector XL Double Door Model second hand and it worked once and than the thermocouple would start sticking making the elements never energize.  So I decided I would just gut the stock electrics and build my own standalone PID box to control the elements within the smoker.  I drew up a quick diagram and would love for someone to check my work before I start working on this.  Sorry about the state of this diagram as I'm really not very good at creating them efficiently. 

    Thanks for the help guys.

     
  2. jckdanls 07

    jckdanls 07 Master of the Pit Group Lead OTBS Member

    looks good to me... The LED is not really needed (but can be seen easier).. as there should be a light on the front of the PID illuminating when the SSR is energized ... good luck with your build...

    Also I wired in an illuminated on/off switch in mine...
     
    Last edited: Nov 24, 2015
  3. jmabrao

    jmabrao Newbie

    The power in is an IEC320 C14 Which is also fused and has a power switch.  Don't really know if it's illuminated though.  The LED I just put it on there for giggles.  May be a bit over kill with 2 fuses and a breaker but It's better safe than sorry I suppose.
     
  4. jckdanls 07

    jckdanls 07 Master of the Pit Group Lead OTBS Member

    I would also suggest using terminal strips instead of wire nuts... just a cleaner build... gonna use a heat sink on your SSR ??
     
  5. jmabrao

    jmabrao Newbie

    Yeah I wan't sure whether to use a strip or not, good point on it being a cleaner build.  I have a cheap aluminum heat sink that the SSR mounts on to. I worry about airflow slightly as there won't really be any.  I anticipate not pulling anymore amps than 12 and the SSR is rated at 40 amps, but no airflow and things start to heat up.
     
  6. jckdanls 07

    jckdanls 07 Master of the Pit Group Lead OTBS Member

    you'll be ok.. just put the heat sink on the outside of the enclosure...
     
  7. jmabrao

    jmabrao Newbie

    Okay so here is an updated schematic, should be about the same aside from using a terminal block as opposed to wire nuts.  Rest of my parts come in on friday. Any other hints you guys can give me before I start?

    Thanks

     
  8. jmabrao

    jmabrao Newbie

    Another thing im worried about is a runaway ssr which could be a fire hazard. Any ideas on how to make a failsafe? The pid doesnt have an alarm so that wouldn't be an option.
     
  9. jmabrao

    jmabrao Newbie




    Well I just finished it up, nothing fancy but it seems to be working great, fingers crossed...  That relay likes to get warm though so I may have to mount a small fan to force air over the heatsink...

    Thanks again for the help
     
  10. bill1

    bill1 Smoke Blower

    That double-ended plug you're using to bring the power in looks scary to me.  What if a child got hold of that?  Why not just bring the power cord in through a hole or a cable gland?  

    If the SSR is getting warm, you don't want its heat sink in a closed box.  Put the sink on the outside.  With the thin plastic wall as an interface you may be OK.  (If it gets too soft, you'll have to get a couple pieces of metal.) 

    Also you're pictorial schematic shows a 12V dc relay.  I assume you bought an "AA" model instead that uses 120V coil/control voltage? 
     
  11. jmabrao

    jmabrao Newbie

    Yes I had thought about that as well but I made it permanently attached to the input so you cant pull it out and have hot terminals exposed. Please enlighten me on what an AA relay is. I probably will find a different way to mount the heatsink just haven't gotten around to it.
     
  12. bill1

    bill1 Smoke Blower

    I just meant the picture shows a Fostek SSR-40 DA which needs DC to switch 40A of AC.  But if it's working, I assume you bought the Fostek SSR-40 AA, which uses AC to switch the AC.  

    So how do you make a plug permanently attached to a duplex receptacle?  
     
  13. thesmokist

    thesmokist Meat Mopper

    Cool setup. I have a CaJun injector xl if something happens to it I'll trying this. If your having a heat issue you could put some holes in one side and a small computer cooling fan on the other to draw air in through the holes to cool it.
     
  14. jmabrao

    jmabrao Newbie

    It's kind of janky I know but I essentially epoxied it in there, and the relay is a DA model because my pid I use puts out a 12v dc output to signal the relay.  I have already made a pretty large hole in one side of the enclosure and a smaller intake on the other, just having a hard time trying to find out what kind of fan to use being that I can't use a 12v dc fan.  I also am having a hard time finding a smaller AC powered fan.

    But yes this PID controlled setup is far superior to the stock control system, with the stock system the temp would swing from 200 - 240 when set at 225, now with this PID controller it stays within a few degrees throughout the cook.
     
  15. bill1

    bill1 Smoke Blower

  16. jmabrao

    jmabrao Newbie

  17. jmabrao

    jmabrao Newbie

    Well I was warming up my smoker this morning and went in the house, little bit later went to check on the smoker and smelled smoke. Whole garage was filled with smoke, and not the good kind.... What do you think caused this? I'm thinking the cheap as dirt relay shorted internally.

     
    Last edited: Feb 20, 2016
  18. thesmokist

    thesmokist Meat Mopper

    Was it all wired up right? If so than yeah the relay probably burnt. Good thing it didn't catch your place on fire!!
     
  19. jmabrao

    jmabrao Newbie

    Yeah it was wired up correctly and working fine... I'm very lucky it didn't cause any damage. I can salvage just about everything except obviously the relay. It really doesn't make any since though because only the live or neutral wire passes through the relay... So how would there be such a catastrophic short in the relay?
     

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