Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

[REQ] Temperature regulation with Pt100

Status
Not open for further replies.

mrcube_ns

Advanced Member level 1
Joined
Apr 10, 2002
Messages
452
Helped
48
Reputation
96
Reaction score
34
Trophy points
1,308
Location
Europe
Activity points
3,814
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

Junior Member level 3
Joined
Oct 7, 2007
Messages
30
Helped
3
Reputation
6
Reaction score
1
Trophy points
1,288
Location
California
Activity points
1,466
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

Advanced Member level 1
Joined
Apr 10, 2002
Messages
452
Helped
48
Reputation
96
Reaction score
34
Trophy points
1,308
Location
Europe
Activity points
3,814
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

Newbie level 5
Joined
Nov 12, 2007
Messages
10
Helped
2
Reputation
4
Reaction score
1
Trophy points
1,283
Activity points
1,324
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.
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top