Hello Avatar;

Toi add to Duris_I's excellent information, here are 2 pointers;

- the typical connection for a 2-wire sensor is shown in the attachment below, taken from the S7-300 Module Data manual (chapter 6, Analog modules)l.

https://support.industry.siemens.com/cs/ww/en/view/8859629

-once you have achieved a reading of a numerical value (0-27648 or -27648-+27648, depending on whether the signa is unipolar or bipolar) in your PLC address corresponding to the analog input channel; selected, you would probably want to see engineering values related to the pressure you are reading in the field, such as 0-5 bar instaed of the numerical values output by the analog input card.

Here is an example for using FC 105 "SCALE" from the TI-S7 converting instructions, to input 0-27648 values and output 0.0-5.0 bar in your program:

How and for which analog measurements can you use the function FC105 "SCALE" to convert the integer values (INT) into real number values?

https://support.industry.siemens.com/cs/ww/en/view/1765297

Hope this helps,

Daniel Chartier

Edit: adding the screenshot from the S7-300 Module Data manual.

Hello Avatar;

You max pressure value la 400.0 bar, your min. value la 0.0 bar.

The result of your conversion is 204.0 bar, or just over 50% of your range; it looks like you have been working in bipolar mode.

Try setting your Bipolar parameter to 0, in your FC 105 call, placing the conversion to unipolar mode; this would be more adapted to a 4-20 mA signal. See the online help for FC 105 for more details; use the F1 key on the function to open the help. Also check on the settings/properties of your analog input card to make sure it is properly set for 4-20 mA readings.

Hope this helps,

Daniel Chartier