MVI56E-MNETC/MNETCXT ♦ ControlLogix Platform MVI56E-MNETC/MNETCXT Configuration
Modbus TCP/IP Client Enhanced Communication Module - Client/Server User Manual
ProSoft Technology, Inc. Page 45 of 172
September 20, 2018
Command List Overview
In order to interface the module with Modbus TCP/IP server devices, you must
construct a command list. The commands in the list specify the server device to
be addressed, the function to be performed (read or write), the data area in the
device to interface with, and the registers in the internal database to be
associated with the device data. The Client command list supports up to 16
commands.
The command list is processed from top (command #1) to bottom. A poll interval
parameter is associated with each command to specify a minimum delay time in
tenths of a second between the issuances of a command. If the user specifies a
value of 10 for the parameter, the command will be executed no more frequently
than every 1 second.
NOTE: If you are using only Event Commands or issuing commands from the Command List using
Command Control from ladder logic, it is likely that the module will not leave any inactive TCP/IP
socket connections open for more than 60-seconds. To maintain an open socket connection, your
configuration or application must be designed so that at least one command is issued to each
server connection at less than 60-second intervals. The 60-second connection timeout is not user-
configurable and was put in place to prevent long delays between commands.
Commands Supported by the Module
The format of each command in the list depends on the Modbus Function Code
being executed.
The following table lists the functions supported by the module.
Force (Write) Single Coil
Preset (Write) Single Register
Force (Write) Multiple Coils
Preset (Write) Multiple Registers