Rockwell Automation 1746-XXXX SLC 500 4-Channel Analog I/O Modules User Manual - Manual (Page 48)

Publication 1746-UM005B-EN-P - June 2004
4-10 Module Operation and System Considerations
fault. Once the fault condition is corrected and the major fault bit in
the processor is cleared, the retained data is sent to the analog output
channels.
If you choose not to use the retentive programming option, retained
data is not sent to the output channels.
The following section provides example program options for retentive
data and non–retentive data.
Retentive Analog Output Example
If a modular system is configured with the CPU in slot 0, a discrete
I/O module in slot 1, and an analog output module in slot 2 the
following ladder logic rung can be programmed.
When bit 0 of the discrete I/O module turns ON, the rung is true and
the value 32767 is moved into the Output Image table location that
corresponds with analog output channel 0 in slot 2. At the end of the
scan, this value is transferred to the module where it is converted to
the appropriate voltage or current (depending on the type of module
used).
If on the next program scan the rung becomes false, the MOVE of the
value of 32767 to the Output Image table does not occur. Unless
another rung is added to transfer data to the Output Image based on
this rung being false, the previous data is retained. That is, the value
32767 remains in the Output Image table and is transferred to the
analog module at the end of subsequent program scans until changed
by the user program.
MOV
MOVE
Source 32767
Dest O0:2.0
] [
I1:1.0/0