ProSoft Technology MVI56E-MNET/MNETXT - Manual (Page 134)

Reference MVI56E-MNET / MNETXT ♦ ControlLogix Platform
User Manual Modbus TCP/IP Interface Module
Page 134 of 181 ProSoft Technology, Inc.
April 23, 2014
5.3.2 Client Driver
In the Client driver, the MVI56E-MNET module issues read or write commands to
servers on the Modbus TCP/IP network. The commands originate either from the
module's user-configured Client 0 Command List, or directly from the processor
as Event Commands. The commands from the Client 0 Command List are
executed either via routine polling or as a result of special Command Control
block requests from the processor. The following flowchart describes the flow of
data into and out of the module.
1 The Client driver obtains configuration data when the module restarts. This
includes the timeout parameters and the Command List. These values are
used by the driver to determine the type of commands to be issued to servers
on the Modbus TCP/IP network.
2 When configured, the Client driver begins transmitting read and/or write
commands to servers on the network. The data for write commands is
obtained from the module's internal database.
3 Assuming successful processing by the server specified in the command, a
response message is received into the Client driver for processing.