S5 and S7 analogue (difference)

Hi,

We have an old S5 rack with analogue inputs 4-20mA (4 DMU (4wire))

We have a redoxmeasure (don't mind redox), it gives it's value to an S7 CPU; in that CPU the value is scaled to -500 tot +500. And when u look on the redox itself it shows the same value.


But, now, I they want another redoxmeasure, but I connected it on a S7 analogo input 4-20mA 4DMU. I used the same scale block for -500 to +500. Result, it doesn't match the redox ?


So, the input of S7 analogue is till 279xx ...

and S5 to 32768 ? If that is so, then I have to change the Offset of my programmed function...

greetz

clear some things up

well, i have to clear some things up...


S7 has an analogue input 4-20mA that gives us an integer of 27912 when we have 20mA @ the input.

What is the integer when we have 20mA on an S5 inputcard ? is it the same or is it 32768 or something like that ?

it's not that simple in S5....the PW contains some status bits as well as the value

....from the 'Simatic S5 Software Reference Guide' (again)

What is the integer when we have 20mA on an S5 inputcard ? is it the same or is it 32768 or something like that ?

Click to expand...

When you have 20mA the analog value is 2048

thanks

thanks krk