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LDmicro Forum - Temperature controler |
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Temperature controler (by Gurt)
Dear All,
I need your help, I have a NTC temperature sensor which will sense temperature continously. I want to compare the last temperature with the previous (FIFO), the moment the temperature samples are equal a relay will switch and I want this relay to be on for 5 minutes. When the relay switches off I want it to stay off for 10 minutes. When I test this, the times are wrong, what am I doing wrong? Thanks in advance! Gurt
(no subject) (by David R)
Hi made small change see if it helps
Regards David
Temperature controler (by Gurt)
Hi David,
Thanks, have to test this on site. Regards Gurt
Temperature controler (by Gurt)
Forgot! To switch the relay on it should be de-energised !
Thanks
Temperature controler (by Gurt)
Hi David, it is working for ONE cycle and then it never switches off. I changed the oven output to negated before testing. In simulation mode it all seems to work but in the real world not. Thanks for the time and effort. Regards
Gurt
(no subject) (by David R)
Hi try this for an idea
Temperature controler (by Gurt)
Hi David, thanks again, will try this today, will let you know the outcome.
Regards, Gurt
Temperature controler (by Gurt)
Hi David still no luck, Will make another tread for my problem.
Thanks again for your effort and time, regards Gurt
(no subject) (by Ronaldo)
See if I'm wrong. reading the temperature sensor to each one second, the current temperature and earlier are equal. The temperature difference will be very small in this time interval. How much is the maximum and minimum temperature? what is your application?
(no subject) (by Ronaldo)
In this example, when both samples are equal,
the out turn on for 5 seconds, and after 15 seconds, restarts the cycle. setting times and see if it works
Temperature controler (by Gurt)
Dear Ronaldo, thanks for the reply, my application is an oven controller for technical springs, the oven should be pre heated (init time 10 minutes) the moment the set temp is ok the oven should stay on for 5 minutes, after that the oven should cool down for three minutes and then start the cycle again
The temperatures are yet to be determined but should be in the range of min 150 degrees C and max 350 degrees C
(no subject) (by Jorge Jacome)
Hi Gurt
Just a quick note, for that temperature range i would suggest a different type of sensor maybe a PT100 or a thermocouple, but in that case you would need a different input circuitry interface to the ucontroller. regards Jorge
Hi Jorge (by Gurt)
You are right, I'm in the learning process of the ucontroller and LD micro, so I started with the software first, when the program works the PCB will be next, thanks for the reply !!
regards Gurt
ntc file (by Gurt)
Hi Ronaldo, could you resend the file again, I cannot open it.
Thanks again, kind regards Gurt
(no subject) (by Ronaldo)
Dear Gurt,
In This file, the Cminuto is the initial counter 10 seconds, which equals the initial time of heating. After this time the temperature is read from the AD, and stores in "sample". If "sample" is greater than 350 the output remains off for 5 sec. elapsed time of 3 seconds, the pin1 output (out) is turned on and starts the cycle. All times are in seconds. To work with minutes to load "Cminuto" rung 10 = 600s; = 10minute rung 11 = 601S; cContequal load: rung 300s = 9 = 5 minute rung 10 = 480 seconds = 8 minute simulate this in ldmicro it will work, change the value of A/D greater than 350 in rung 6. The minimum temperature was not used in this code example. Regards, Ronaldo
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