ProSoft Technology MVI56E-MCM/MCMXT - Manual (Page 53)

MVI56E-MCM ♦ ControlLogix Platform Configuration as a Modbus Master
Modbus Communication Module User Manual
ProSoft Technology, Inc. Page 53 of 199
June 18, 2014
2.5.1 Command Control
Command Control allows you to issue a command already defined in the Master
command list (but disabled) and enable that command for a single pass.
Command Control has a distinct advantage over Event Command in that it will
still return an error code for that command as configured in
MCM.CONFIG.P
ORT X.C MD E RR P TR . Up to 6 commands may be enabled at the
same time.
The following illustration shows how to configure Command Control using the
MCM.UTIL.C
MD C ONTROL object in the ladder logic.
The following configuration will place 6 commands into the command queue.
MCM.CONFIG.P ORT 1M ASTER C MD [0] to MCM.CONFIG.P ORT 1M ASTER C MD [5]
will be enabled with this configuration. Error codes for each command are placed
in the Error Status table.
Tag Value Description
TriggerCmdCntrl 1 1 will execute the Command Control
NumberOfCommands 6 Number of commands per block
PortNumber 1 MVI56E-MCM Port number (Master)
CommandIndex[0] to [324] 0 to 324 Stores the command index for Command Control
block
CmdsAddedToQueue Number of commands added to queue. This is the
confirmation that the Command Control block has
completed successfully
CmdControlBlockID Temporary variable to calculate control block ID
number
CmdCntrolPending Aux. control command - prevents a second request
before acknowledgement is received
Note: For RSLogix version 15 and lower, the ladder logic necessary for the successful execution of
this block is contained in the _WriteControl ladder file, rung 4, and in the _ReadControl ladder file,
rung 2.