ProSoft Technology MVI46-MCM - Manual (Page 65)

MVI46-MCM ♦ SLC Platform Reference
Modbus Communication Module User Manual
ProSoft Technology, Inc. Page 65 of 108
March 29, 2011
Event Command Blocks (1000 or 2000)
Event command control blocks send Modbus Master/Slave commands directly
from the ladder logic to one of the master ports.
Block Request from Processor to Module
M1 Offset Description Length
7800 1000 or 2000 1
7801 Internal DB Address 1
7802 Point Count 1
7803 Swap Code 1
7804 Node Address 1
7805 Function Code 1
7806 Device Address 1
The block number defines the Modbus Master/Slave port to be considered. Block
1000 commands are directed to Port 1, and block 2000 commands are directed
to Port 2. Use the parameters passed with the block to construct the command.
The Internal DB Address parameter specifies the module’s database location to
associate with the command. The Point Count parameter defines the number of
registers for the command. The Swap Code changes the word or byte order. The
Node Address parameter defines the device on the Modbus Master/Slave
network to consider. The Function Code parameter is one of those defined in
the ProSoft Modbus Master/Slave Command Set documentation. When the block
is received, the module will process it and place the command in the command
queue.
Block Response from Module to Processor
M0 Offset Description Length
0 1000 or 2000 1
1 0=Fail, 1=Success 1
The ladder logic can use Word one of the block to determine if the command was
added to the command queue of the module. The command will only fail if the
command queue for the port is full (100 commands for each queue) or the
command requested is invalid.