[REQ] Temperature regulation with Pt100

[mrcube_ns]

pt100 comparator

Hi all,

I have heater 300W and Pt100, and I have to made temperature regulation.

This regulation doesn't have to be very precise - target temp. should be around 50 deg. and temperature oscilations of a few degries around set value is OK for this application.

Any ideas, links or comments are welcome.

Thanks in advance.


Mr.Cube

PS.
My basic idea is:
1. Convert resistance of Pt100 to voltage (0- 100C => 0 - 10V with op. amp.)
2. Made Reference voltage with potentiometer => 0-10V
3. Those two signals use as input ones in op. amplifier with hysteresis.
4. On op. amp, with hysteresis, output connect triac gate via MOC3040 or similar opto-coupler, and triac will switch on and off heater.

 

[leftyretro]

pt100

Do a search on PID control. That is a classic feedback control algorithm. There are many available source code implementing PID for many compilers and assemblers.

Lefty

 

[mrcube_ns]

leftyretro
I agree with you, but I think that ON/OFF regulation is good enought, in this case.

I just need something simple, with Pt100 as sensor. Accuracy of +-3 or 4 degrees is OK.

Mr.Cube

 

[heychel]

In your case, I use a comparator with pt100 on positive input and a pot of a few ohms and two adapted resistors on negative input; positive feedback will made the hysteresis; for the output, use a relay or an optotriac. Take care of self heating of the pt100, current as low as measurable.