Rockwell Automation 1746-XXXX SLC 500 4-Channel Analog I/O Modules User Manual - Manual (Page 49)

Publication 1746-UM005B-EN-P - June 2004
Module Operation and System Considerations 4-11
Non-Retentive Analog Output Example
The following example shows a non-retentive program during a
program execution and for a mode change or power cycle.
In the above example, as long as discrete input 0 is ON, the value
32767 is transferred to analog output channel 0. If discrete input 0
turns OFF, the value 0 is transferred to analog output channel 0.
During a Mode Change or Power Cycle
The first pass bit in the Status File is used to initialize the analog
output following a power up in the RUN mode or entry into the RUN
or TEST mode. The address of the First Pass bit is S2:1/15. When this
bit is ON, the first pass of the program scan is taking place. Therefore,
the following ladder rung can be programmed to always clear the
analog output channel during the first program scan.
Input Out-of-Range Detection
Analog modules do not provide an input out-of-range signal to the
processor. However, if this feature is critical to a specific application,
you can program the processor to provide this function.
The following program applies to all SLC 500 processors. The program
shows two compare instructions that check for analog input values
MOV
MOVE
Source 32767
Dest O0:2.0
] [
I1:1.0/0
MOV
MOVE
Source 0
Dest O0:2.0
] [
I1:1.0/0
/
MOV
MOVE
Source 0
Dest O0:2.0
] [
S2:1/15