Publication 1766-RM001A-EN-P - October 2008
602
Protocol Configuration
Monitor Active Stations
To see which slave stations are active when the channel is configured for
Standard Polling Mode (either single or multiple message per scan), view
the DF1 Half-Duplex Master Active Node Table. The table is stored in the
Communications Status Function File, words CSx:27…CSx:42, where x is
the channel number (x = 0 for MicroLogix 1400). Each bit in the table
represents a station on the link, from 0…254, starting with CSx:27/0 for
address 0 and CSx:42/14 for address 254. The bit for address 255 (CSx:42/
15) is never set, since it is the broadcast address, which never gets polled.
When valid Normal and/or Priority Poll Ranges are defined:
•
if a slave responded the last time it was polled by the master, the bit
corresponding to its address is set (1 = active).
•
if a slave didn’t respond the last time it was polled by the master, the
bit corresponding to its address is cleared (0 = inactive).
If you are using RSLogix 500/RSLogix Micro version 7.00.00 or higher,
you can view the active node table by clicking on “Processor Status” and
then selecting the tab for the DF1 Master channel.
Example Active Node Table
At power-up or after reconfiguration, the master station assumes that all
slave stations are inactive. A station is shown active only after it responds
to a poll packet.
NOTE
The bit corresponding to the address configured for the DF1 Master is
always cleared because the master address never gets polled.
efesotomasyon.com - Allen Bradley,Rockwell,plc,servo,drive
