Siemens S7300, PT100 input -> 4-20mA output

Hi.

I use a PT100 ipnut on a SM331 analog input module. To control the temperature in a hydraulic transmission circuit.

All I do to get right temperature displayed is this;

L PIW 290
ITD
DTR
L 1.000000e+002
/R

And my problem is:

I want to log this temperature in LabView, and the input module there is 4-20mA.

How can i send out the temperature signal from the PLC as 4-20mA?

I have tried to just move the signal from PIW 290 (PT100 input) to PQW 304 (output to LabView). The scaling isn't right.

Use the FC106 UNSCALE block in the TI-S7 library.

Well, i tried that now, and i didn't get it to work.

Could you be so kind and explain more?

Wich input do i use? I cant use PIW290 straight away.

What range do you want on the LabView input?

4mA = ?
20mA = ??

Kalle

JesperMP said:

Use the FC106 UNSCALE block in the TI-S7 library.

Click to expand...

Wherever you put the scaled value that comes from the "Scale" function FC105, (A Datablock "Real" value?)use that value and "Unscale" it with FC106 and set the engineering units to match 4 and 20mA as Kalle Olsen suggests

How did you arrive at this code ?
What unit is temperature in after the /R

Temperature is in Celsius, got it from someone on this forum.