Rockwell Automation 1403-NENET Ethernet Communication Card Installation Instructions - Manual (Page 61)

1 Publication 1403-IN005A-EN-P
Appendix
C
Sample Ladder Listing
Ladder Program
Description This appendix contains sample ladder programs that interface to the
Powermonitor II for SLC-5/05 Ethernet. Rung-by-rung descriptions follow.
SLC 5/05 Ethernet Operation
There are three modes of operation:
•
Configuration
•
Setpoint
•
Run
Each mode uses a single Sequencer Output Instruction in order to process the
required MSG transfers. There are only two MSG transfers required. These
two MSG transfers are repeated until each mode is completed successfully. For
Run mode, the number of MSG transfers processed by the sequencer is
variable. Because there is only one sequencer to be used for three modes, the
sequencer’s input file must be updated at the beginning of each new mode. The
numbers corresponding to the MSG transfers required for each mode are
contained in three separate files. The content of each file is moved to the
sequencer’s input file at the beginning of its corresponding mode.
Configuration Mode
During initialization of Configuration mode, the sequencer input file is loaded
with the two numbers. These numbers correspond to the configuration table
MSG Write and the diagnostic table MSG Read. The sequencer length is set to
2. After completion of the configuration data MSG Write, a diagnostic table
MSG Read is performed to verify that the MSG Write was successful. If the
configuration table MSG Write is successful, the Configuration mode bit is
unlatched and the setpoint mode bit is latched. If the MSG Write is not
successful, the configuration table MSG Write and diagnostic table MSG Read
sequence continues until the problem is corrected. This most likely requires a
change in the configuration table data.
Setpoint Mode
During initialization of Setpoint mode, the sequencer input file is loaded with
the two numbers. These numbers correspond to the setpoint data table MSG
Write and the diagnostic data table MSG Read. The sequencer length is set to
2. Also, the number of setpoints is written to a counter which is used to