ProSoft Technology MVI71-MNET - Manual (Page 60)

MVI71-MNET ♦ PLC Platform Reference
Modbus TCP/IP Interface Module User Manual
Page 60 of 109
ProSoft Technology, Inc.
June 23, 2009
Main Logic Loop
Upon completing the power up configuration process, the module enters an
infinite loop that performs the functions shown in the following diagram.
Call I/O Handler
Call CFG/DEBUG Port
Driver
Call Network Client &
Server Drivers
Call I/O Handler
Transfers data between the module and processor
(user, status, etc.)
Call Serial Port Driver
Rx and Tx buffer routines are interrupt driven. Call to
serial port routines check to see if there is any data
in the buffer, and depending on the value, will either
service the buffer or wait for more characters.
Call Network Client & Server Drivers
Generate messages and
respond to messages received.
From Power Up Logic
Block Transfer Backplane Data Transfer
The MVI71-MNET module communicates directly over the PLC backplane for the
block transfer interface. Data is paged between the module and the PLC
processor across the backplane using BTR and BTW operations. Data is
transferred from the module to the processor using the BTR blocks, and data is
transferred from the processor to the module using the BTW blocks.