ProSoft Technology MVI56E-MCM/MCMXT - Manual (Page 54)

Configuration as a Modbus Master MVI56E-MCM ♦ ControlLogix Platform
User Manual Modbus Communication Module
Page 54 of 199 ProSoft Technology, Inc.
June 18, 2014
2.5.2 Event Command
Event Command allows you to add commands directly to the command queue,
interrupting the normal polling sequence of the module. Unlike Command
Control, Event Commands do not return an error code into the location defined
by the MCM.CONFIG.P
ORT X.C MD E RR P TR value.
You do not need to define Event Commands in the regular command list. Event
Command adds a command to the top of the MVI56E-
MCM module’s command
queue that is not defined within the command list.
Within an Event Command block, you define a Modbus command to add to the
queue.
Important: Because these special command blocks will interrupt the normal polling list, you should
use them sparingly, to avoid interrupting your normal data transfer. Make sure that the data to be
written to the Slave contains the latest value from the WriteData tag that corresponds to the Event
Command.
The following illustration describes the structure of the EventCmd block.
Parameter Value Description
EventCmdTrigger 1 1 = trigger the Event Command
EventCmdPending Used = EventCommand is executed once
PortNumber 1 Module Port # to send command out to
SlaveAddress 1 Modbus Slave ID command to be issued to
InternalDBAddress 1100 1100 will place the data read into
MCM.DATA.ReadData[100]
PointCount 10 Consecutive register/bits to read or write with the
command
SwapCode 0 Swap code used with command
ModbusFunctionCode 3 Function Code 3 is read 4xxxx holding registers
DeviceDBAddress 276 Address in the Slave device to read. With Function
Code 3, DeviceDBAddress of 276, the module will
read starting at address 40277 in the Slave device
EventCmdStatusReturned Return value of 0 = Fail, 1 = Success
EventBlockID Block ID number for the module to recognize the
Event Command, Slave address, and Port number
to send the command out