Rockwell Automation 1746-XXXX SLC 500 4-Channel Analog I/O Modules User Manual - Manual (Page 82)

Publication 1746-UM005B-EN-P - June 2004
6-20 Programming Examples
Scaling and Range
Checking and Analog
Inputs and Outputs This example demonstrates the addressing of analog I/O and the
scaling and range checking of analog input and output values. An
NIO4V is placed in slot 1 of an SLC 500 system. A 0 to 200 psi
pressure sensor is input as a 4 mA to 20 mA signal to input channel 0.
The input value is checked to ensure it remains within the 4 mA to 20
mA range.
It is then scaled and output as a 0 to 2.5 volt signal to a panel meter
pressure display connected to output channel 0. If an out–of–range
condition is detected a flag bit will be set. The scaling operation is
shown below.
The graph displays the linear relationship between the input value
and the resulting scaled value.
Scaled
Value
Input Value
(input min.)
16384
(input max.)
3277
8192
(scaled max.)
0
(scaled min.)