Rockwell Automation DAG6.5.8 APPLICATION GUIDE SCADA SYSTEM - Manual (Page 242)

Publication AG-UM008C-EN-P - February 2005
7-16 Configuring Logix Controllers
Monitor Active Stations
To see what stations are active, view the active station tag. Each bit in
the tag represents a station on the link. The stations are numbered in
order as a continuous bit-stream file starting with the first bit in the
first word (Figure 7.4). If the bit is a one, the station is active; if the bit
is a zero, the station is inactive.
Figure 7.4 Example Active Station File
Configuring a
Message-Based Mode DF1
Half-Duplex
Master Station
Choose message-based communication mode if you want to use MSG
instructions in user programming to communicate with one station at
a time. If your application uses satellite transmission or public
switched telephone network transmission, consider choosing
message-based. Communication to a slave station can be initiated on
an as-needed basis.
With message-based mode, you do not have an active station file that
you can use to monitor station status. Also, you cannot implement
slave station-to-slave station messaging over the telemetry network.