Marcos Electronic Blog: PT100

This practice consists on measuring temperature using a PT100, an arduino and LabVIEW.

Things we need:
-1 Computer with LabVIEW
-1 PT100
-1 Power supply
-6 Resistors (2 of 1k, 1 of 100 ohms and 3 of 1 ohm)
-Wires
-1 Arduino

To make this practice, the first thing that we have to do is to design the circuit that we will use to read the temperature. there, we will use the arduino to read the difference of voltage between A and B, like a Wheatstone Bridge.

Then we will make calculate the resistance of the PT100, extracting it's value in function of the read volts, like this:

The next thing that we have to do is to open the datasheet of the PT100 and copy its values of temperature in proportion with the resistance that we have calculated in a database of Access.

The next thing that we have to do is to create a data link, that it's like a bridge between the database and LabVIEW. To do that, we have to click on: Tools -> Create Data Link and then, we will follow the instructions.

Then, the program will be like this:

The code of the program will be this:

On the first image, we can see how do we open the database (the *.udl file)

In these other two pictures, we start the Arduino and we read it's value. Then, we calculate it to get the resistance of the PT100 and finally, we compare it to the nearest value in the table.