Temperature controller using 89c51

[juju1984]

my project is as below....
i need to design a microcontroller(89c51) based temperature controller(thermostat)....My circuit must include a sensor(AD590),and analog to digital converter(ADC0809),a DAC0800,and a triac(BTA12) or relays to control the heater or cooler......though i have these components at hand,iam unable to design a circuit.I need help abt how to connect all these components together(i.e. how to connect the sensor to ADC,ADC to Microcontroller,Microcontroller to DAC and then DAC to triac)....i would be very grateful if u guys can kindly help..

 

[pop]

As I have never used 89C51(I'm a pic user), I cannot help you on the ways of connecting some of these devices. So here is atleast a schematic on connecting your microcontroller to the triac via opto-triac MOC3023-M. The microcontroller must send out a pulse that is about 100usec wide to ensure correct triggering of the triac.

Also, you will need a zero crossing circuit that will generate an interrupt for your microcontroller so that you can control your triac firing pulse. If you run into some problems with zero crossing circuit, some people from this forum have already helped me out in fixing that. https://www.electro-tech-online.com/threads/gsm-autodialer-for-burglar-alarm.13470/

 

[bmcculla]

You can buy an opto isolated triac driver with built in zero crossing detect. A Bang-bang controller would be the easiest - when the temperature is too low you turn on the heater and when the temp is too high you turn off the heater. Depending on your sensor setup you can get fairly good regulation.

 

[gas]

you should know how the AD590 works first, that means it could transfer the temperature to voltage or current, and if voltage, you can use a amplifier to magnify the voltage or if current, a circuit that change current to voltage should be used, then use the ADC0809 to become digital signal for 89c51.
(sorry for my poor expression)

 

[n ranjan]

i hv designed a temp controller with AD590 with pic controller for controlling temp between 0-80 deg c. do u stil need the answer or hv u already solved

 

[kingsden]

N ranjan can u pls send me the circuit for control of temp using AD590 and PIC

 

[thaithanh]

for circuit simple you can use LM35 for temp sensor,if you have lm35 i can give you crcuit digram.

 

[kingsden]

I require a circuit with DS1620 or AD590( as dese r available) and PIC16f877a.