ProSoft Technology MVI46-MBP - Manual (Page 55)

Reference MVI46-MBP ♦ SLC Platform
Modbus Plus Communication Module
ProSoft Technology, Inc. Page 55 of 101
February 19, 2008
Bit Position Name
0
1
2
3
4
5
-
-
-
199 Event Commands #1
Event Commands #2
Event Commands #3
Event Commands #4
Event Commands #5
Event Commands #6
-
-
-
Event Commands #200
Execution status can be monitored in the same fashion as other commands in
the Master Command List, via the Master Command Status block.
Successful Execution
If the command was successful (Status Code = 0x01), the status will be
maintained as long as the Event Command bit is set. After the enable bit is
cleared, the Status Code field will go to zero (0).
Unsuccessful Execution
If the command was unsuccessful (Status Code > 0x01), the status will be
maintained until the command executes successfully. The ladder logic must 're-
submit' the command (clear the enable bit and set it again) in order for the
command to execute again.
5.2.4 Dual Port Operation
Some Modbus Plus modules are equipped with a second, redundant Modbus
Plus port. A Dual Port Modbus Plus network is implemented in the following way:
ƒ
The primary network connects to Port 1 on all modules.
ƒ The secondary (backup) network connects to Port 2 on all modules.
If the primary network connected through Port 1 fails (for example, if a cable is
cut or disconnected), the network connected through Port 2 will become active,
maintaining the connection between devices.
Important: All Modbus Plus nodes on a network must be equipped with dual ports in order to
implement redundant port operation.