Table of Contents
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1. GENERAL DESCRIPTION
MELSEC-A
1.3
Data Communications
in the
No-Protocol Mode
1.3.1
What is n o - p r a t o c o l mode?
No-protocol mode is a function to permit data communications between the
computer link module and the external device in any data format (no specific
format, such as dedicated protocols, is determined on the computer link
module).
In the no-protocol made, a sequence program for transmitting or receiving
data to/from the computer link module is required.
Data written from the sequence program into the buffer memory area of the
computer link module will be transmitted as it is to the external device on a
request to send.
Data received from the external device, on the other hand, will be stored into
the buffer memory area of the computer link module, and the sequence
program can read it out in the original code.
1.3.2
Applications of
the
wprotocol mode
Interaction between the PC CPU and the computer
Any data can be transmitted and received between the sequence pro-
gram and the computer.
Data logging
Data stored in the PC can be printed out on a printer through the
RS-232C
interface.
Printing out daily
production report
PC
Printer
Reading out data from a terminal
Data can be read out from
a bar code reader and used in the PC.
Bar code reader
1 - 5
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