# trouble with programming PID temperature controller



## rich1003 (Jun 13, 2014)

I completed mounting a "REX C700" PID controller.
Suddenly, I am unable to go and change any parameters in the "LCK" menu.

I have changed the initialization mode in to "o" and held set, still will not change.

Does anyone know if there is a "master reset" mode on these thngs?
Thanks for any input from anyone.


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## dward51 (Jun 14, 2014)

LCK should be set to one of the following, but not "0000" which is what I take you meant by saying it was 0.  Change it to "0100" until you get the PID tuned then change it to "0110" so only the cook temp can be changed.  Check this first (see page 6 of the manual)

0100 - all parameters can be changed (factory set default value)

0101 - no parameters can be changed (all locked)

0110 - set value can be changed

Spec sheets shows it has non-volatile memory so pulling power will not reset it. Says the storage is good for 10 years.  I did not see any jumper data for resetting the memory.


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## rich1003 (Jun 14, 2014)

Thanks for the tip. I think this is a chineese knock-off or the real REX C700, it only came with 1 page (front & back) of instructions.
Now that you explained the LCK modes, it makes sense.

Still trying to figure out the settings. I watched a vid on Youtube that explains in general terms the theory of PID so now I have a basic understanding.
I set SL2 (under COD-0000) to value 0001 but it still reads in ° F (not too worried about that).
Still trying to make sense out of the P,I,d,AR,and oH settings.
I have a small 12vdc fan on the N.O. contacts of the relay and want to hold temp at 225° (107°C).


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## dward51 (Jun 15, 2014)

Here is the link to the REX C700 manual on the RKC Instruments website.  Not sure if these instructions apply to a knock of version though so your mileage may vary.

http://www.rkcinst.com/english/pdf_manual/imnzc21e1.pdf

Here is another manual in a little different format that may be easier to follow

http://files.engineering.com/downlo...-0c8e-4a0a-a8de-0e8bb6212e63&file=c100set.pdf.

I would get it running and try an auto tune before I started fiddling with too many of the PID settings manually. 95% of the time auto tune does the job for you.  You may only need to provide minimal tweaks from there as opposed to trying to figure out all the settings by trial and error.


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## rich1003 (Jun 15, 2014)

Again, thanks for the advice. I'm getting a pork shoulder this afternoon and plan to use it.
I just dove into this feet first without realizing exactly what a PID controller is and does.
Now, I am understanding more. Havn't decided wheather to use the alarm for overtemp or

undertemp yet. I'm thinking overtemp at this point. Probably will use a loud piezo and run

phone wire in the house just in case it the temp ramps up too high.
Can't wait to get started.


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## rich1003 (Jun 16, 2014)

ttt.jpg



__ rich1003
__ Jun 16, 2014






Everything turned out great!
I use it with my Big green Egg so I call it my temperature rEGGulator.
First cook kept it within ±15°. After some work, figured out the settings

that I had changed and returened them to 'factory setting"
Second cook kept temp EXACTLY on temp the whole time.
Fabricated all the housings myself,  Total cost : $22.


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