Interfacing of Pt100 with PIC controller

Thread Starter

embpic

Joined May 29, 2013
189
i am using pic16f876a controller and need to interface pt100 with pic. So after googling i found there is some 2,3,4-pin configuration
for connection. so i am bit confuse to connect this pt100 with pic controller. as my pt100 has only two wire which rod type.
so how to interface pt100 with PIC.
 
All PT100 sensors are 2 wire, it's the wires to the sensor that can be 2, 3 or 4.

Since the resistance change is small, one has to compensate the lead resistance.
In a 2 wire connection, or when the wires are short, compensation isn't necessary.

In a 4 wire system, you can think of Force and Sense terminals. One pair may force a voltage at the sensor and the other will measure the voltage at the sensor, thus lead resistance is removed from the equation. Current is current through the circuit and in a 4-wire system, it doesn't matter the resistance of the ammeter/leads.

In a 3 wire system, one assumes that the resistance of the wires are identical, so 2x, the drop of force wire is compensated, Saves cabling costs.
 

Thread Starter

embpic

Joined May 29, 2013
189
thank you and sorry for late reply.
circuit you provided is can measure only upto 100 degree celcius right??
but i am looking for to read temperature upto 300.
so what changes require for this circuit. and i think instrumentation aplifier will be strong option.
 
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