Table of Contents
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● A user program should process the creation and transmission of command messages to
connected devices, and the reception of responses therefrom. Data transmission / reception
with external devices is handled through data registers and other given operation memories.
● For transmission, a command aligned to a connected device is ASCII converted into a string,
and set to a given data register. The F159 (MTRN) instruction is executed to send a
command.
● For reception, a response received from a connected device is temporarily stored in the
buffer. The F159 (MTRN) instruction is executed to receive a response. The received ASCII
string data is converted into numerical data, etc. based on a user program.
● The maximum data that can be sent at a time is 2,048 bytes (including control codes). The
maximum data that can be received at a time is 4,096 bytes (including control codes).
PLC
■
Purpose of general-purpose communication
Used for connection with devices from other manufacturers that have specific communication
protocols.
WUME-FPXHCOMG-02
Data register (DT)
Send a command aligned to an
Send data
Receive data
1.2 Overview of Communication Functions
external device
Receive a response from an
external device
RS-232C, RS-485,
etc. (commercially
available)
1-7
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