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PT300 Temperature Sensor Interfacing

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Bjtpower

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Hello Friends

I am planning to develop a circuit of Temperature Sensor with PT100-3Wire

i understand that it need a constant current source so we can measure very precise change in Temperature.

Now 2 mA of current Source i will to make and pass it through the Temperature Sensor..

I dont know how to generate 2 mA of current source.

Kindly help me out

Regards
Marx
 

Linear, Analog Devices, and other have several app notes on the best practices for a PT sensor.

But the sensor being resistive, I would think that a Wheatstone bridge configuration followed by an amplifier with very good CMRR would be the proper solution.
 
Re: Pt100 Temperature Sensor Interfacing

Advantage of constant current source is having linear R-to-V characteristic. In can be easily combined with 3- or 4-wire circuit to compensate cable resistance influence. As said, there are tons of application circuits available.

If no cable compensation is required (2-wire circuit), a simple voltage divider with an accurate reference resistor gives good results.
 

I would stay with a 3-wire measurement if you want to measure precise temperatures.

Over what temperature range do you need to measure?
 

I am having 3 wire PT300..

Want to measure a temperature from 0 degree to 200 degrees

I seen the application somewhere telling that passing a constant current would give us the better result.

In whetstone bridge, where i can connect 3rd wire..??

Whetstone bridge is good for the 2 wire PT100..
 

Here's an article on a precision current source that may be helpful.

To what accuracy do you want to measure the temperature?
 
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Typing in "pt100 3-wire circuit" at Google gives many hits, e.g. TI application notes.
 

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