Hello,

you don't need the exact resistance of the PT100. You just need to know what range it has (seen in data sheet for the PT100). Standard is 0..850°C.

For reading the value to PLC and calculating it you can use the Siemens FC105 "SCALE". You'll find it in the Standard Library -> TI-S7 Converting Blocks. On the Input "IN" you give the PIW of PT100 and on scaling inputs "HI_LIM" and "LO_LIM" you write the range (0, 850) in REAL-Format. On the Output "OUT" you get the calculated value back in REAL-Format.

hope this helps.

nice regards

Kampi

Hello,

you don't need the exact resistance of the PT100. You just need to know what range it has (seen in data sheet for the PT100). Standard is 0..850°C.

For reading the value to PLC and calculating it you can use the Siemens FC105 "SCALE". You'll find it in the Standard Library -> TI-S7 Converting Blocks. On the Input "IN" you give the PIW of PT100 and on scaling inputs "HI_LIM" and "LO_LIM" you write the range (0, 850) in REAL-Format. On the Output "OUT" you get the calculated value back in REAL-Format.

hope this helps.

nice regards

hi amirhm, hi Kampi,

it is right. you don´t need the exact resistance.

But you also don´t need the scale function

It allready show´s you the temerature. Have a look to following manual, chapter 5.1, page 280:

SIMATIC S7-300 S7-300 Module data

hope this helps,

regards,