ProSoft Technology MVI69-GEC - Manual (Page 58)

Contents MVI69-GEC ♦ CompactLogix or MicroLogix Platform
User Manual
Page 58 of 86 ProSoft Technology, Inc.
February 18, 2014
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
Backplane Data Transfer
The MVI69-GEC module communicates directly over the CompactLogix or MicroLogix
backplane. Data travels between the module and the processor across the backplane using
the module's input and output images. The update frequency of the data is determined by
the scan rate defined by the user for the module and the communication load on the
module. Typical updates are in the range of 1 to 10 milliseconds.
Data received by the servers is placed in the module's input image. This data is processed
by the ladder logic in the processor. The input image for the module is set to 60 words. This
large data area permits fast throughput of data between the module and the processor.
The processor inserts data in the module's output image to transfer to the module. The
module's program extracts the data and transmits the data out to the Ethernet network.
Each message is directed to a server that is connected to a client in a remote host. This
large data area permits fast throughput of data from the processor to the module.