MVI46-GEC
♦
SLC Platform
Reference
Generic ASCII Ethernet Interface Module
Page 46 of 78
ProSoft Technology, Inc.
April 30, 2008
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 MVI46-GEC module communicates directly over the SLC backplane. Data
travels between the module and the SLC processor across the backplane using
the module's M0 and M1 files. The update frequency of the data is determined by
the scan rate of the ladder logic in the SLC processor.
Data received by the servers is placed in the module's M1 file. This data is
processed by the ladder logic in the SLC processor. The M1 file for the module is
set to 500 words. This large data area permits fast throughput of data between
the module and the processor.
The processor inserts data in the module's M0 file 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 and each message may be directed to a client that is connected to a
remote server. The M0 file for the module is set to 500 words. This large data
area permits fast throughput of data from the processor to the module.
