Hi, 

I have a simple question about 4-20mA analog input (using CPU 1510, TIA v14).

The range of the analog input signal (from temperature transmitter) is: [4mA, 20mA] (%IW)
The range of the PLC variable (type Int) is: [5530, 27648] (min, max of NORM_X)
The range of the temperature readings from technical data sheet is: [-20 deg.C, 120 deg.C] (min, max of SCALE_X)

My question is:
If my application has a smaller range than the sensor range, e.g. between 20 deg.C to 50 deg.C., in the SCALE_X function is it wrong if I put MIN=20 and MAX=50, or should I put MIN=-20, MAX=120 as per sensor data sheet?

Thanks, 
Erik  

It is your sensor range you should use, irrespective of the kinda application you have. Otherwise your temperature readings will be totally wrong.

Thanks,

Jay

Hello Erik_C,

in my opinion should you configure your analog input module to 4..20 mA.
Actually looks like a configuration 0..20 mA.

If you configure your the module to 4..20 mA then you have a %IW-range
0...27648 and a temperature range between -20..120 dregree C.

You should scale the value (X_Scale) between -20 and 120.
The technical range is the right range.

regards
CaOd 

Thanks for all the advices.

@CaOd, how do I configure the analog input module to 4..20 mA.?

Regarding the sensor range, in the technical specs it gives in fact 2 upper limits, one for continuous mode of operation (120degC) and another for short term operation (150degC).
In this case, which one would be correct as the Max SCALE_X, 120 or 150?

Kind regards, 

Erik