Mitsubishi A1SJ71(U)C24 Connection Guide

Help Contents

Introduction

The A1SJ71(U)C24 computer link module provides a serial communication link to a Mitsubishi A-Series PLC. Applications, such as Fernhill SCADA, can use the module to monitor and control a Mitsubishi A-Series PLC.

The information in this guide applies to a range of Mitsubishi Melsec A-Series computer link modules:

ModuleInterface
A1SJ71UC24-R2RS-232 computer link module
A1SJ71UC24-R4RS-422/485 computer link module
A1SJ71C24-R2RS-232 computer link module
A1SJ71C24-R4RS-422/485 computer link module

The rest of this article uses the name A1SJ71C24 to refer to any of the above modules.

There are two types of connection on the A-Series serial communication modules:

Connection TypeDescription
RS-232 DE-9RS-232 using a D-Subminiature 9 pin female connector
RS-422/485 Screw TerminalsRS-422/485 using a screw terminals

Connection Cables

RS-232 Connection

The RS-232 port on an A1SJ71C24 can connect directly to a serial port on a Personal Computer (PC). The serial port on a PC is usually a 9 pin D-subminiature connector. To connect the A1SJ71C24 to a PC, a connection cable with this wiring is required:

A1SJ71C24 RS-232
D-Subminiature connector DE-9 plug wiring side shown
PC
D-Subminiature connector DE-9 socket wiring side shown
RXD23TXD
TXD32RXD
DTR46DSR
GND55GND
DSR + DCD6 + 14DTR
RTS78CTS
CTS87RTS

Note: All other pins not shown in the above diagram have no connection.

RS-422 Connections

Use this table to select the appropriate wiring between the screw terminals on the module and common RS-422 adapters:

Mitsubishi Melsec
RDA RDB SDA SDB
Advantech
ADAM-4520
TX+ TX- RX+ RX-
StarTech
IC485S
IC485SGB
IC485SEU
1 (TX-) 2 (TX+) 4 (RX-) 3 (RX+)

For more information about connecting a PLC Device to a computer using an RS-422 link, see RS-422 Communication with PLC Devices.

Configuring Serial Communications

Setting up a serial communication link can be difficult because of the wide variety of communication options. For example:

For Fernhill SCADA to communicate with an A1SJ71C24 module, both need use the same communication options. There are a two main ways to achieve this:

Manual Configuration

The A1SJ71C24 module is configured by front panel switches.

Fernhill SCADA is configured using properties of the Channel and PLC tags:

The relationship between A1SJ71C24 front panel switches and Fernhill SCADA properties is:

A1SJ71C24 Switch Fernhill SCADA Property
Station No StationNumber in the Mitsubishi Melsec PLC Tag
Mode CommFormat in the Mitsubishi Melsec serial channel
SW05-SW11 Mode in the Mitsubishi Melsec serial channel

Note: The Station No switch is not fitted to the R2 variants of the module.

The rest switches on the A1SJ71C24 Computer Link module should be set to these positions for correct operation:

A1SJ71C24 SwitchSetting
SW03Off
SW04On (Allow write during RUN)
SW12On (Use sum check)

Station No

The StationNumber property of the Mitsubishi Melsec PLC Tag should be set as follows:

Mode Switch

The Mode Switch can be set to 1, 2, 3 or 4. The CommFormat property of the Mitsubishi Melsec serial channel should be set to the matching value:

Mode SwitchCommFormat
1Format 1
2Format 2
3Format 3
4Format 4

SW05 to SW07

SW05 to SW07 define the baud rate of the communication channel. The Mode property of the Mitsubishi Melsec serial channel should contain a matching Baud clause:

SW05SW06SW07Mode String Clause
OffOffOffBaud=300
OnOffOffBaud=600
OffOnOffBaud=1200
OnOnOffBaud=2400
OffOffOnBaud=4800
OnOffOnBaud=9600
OffOnOnBaud=19200

SW08

SW08 defines the number of data bits in each character transmitted on the communication channel. The Mode property of the Mitsubishi Melsec serial channel should contain a matching Data clause:

SW08Mode String Clause
OffData=7
OnData=8

SW09 and SW10

SW09 and SW10 define the parity bit added to each character transmitted on the communication channel. The Mode property of the Mitsubishi Melsec serial channel should contain a matching Parity clause:

SW09SW10Mode String Clause
Off*Parity=N
OnOffParity=O
OnOnParity=E

Note: The asterisk (*) means not applicable.

SW11

SW11 defines the number of stop bits in each character transmitted on the communication channel. The Mode property of the Mitsubishi Melsec serial channel should contain a matching Stop clause:

SW11Mode String Clause
OffStop=1
OnStop=2

For more information refer to the A1SJ71C24 User Manual.

Further Information

Mitsubishi Melsec Serial Autodetect Wizard

For how to automatically configure Fernhill SCADA to communicate with a Mitsubishi serial communication module.

Mitsubishi Melsec serial channel

For information about Mitsubishi Melsec serial channel configuration.

Mitsubishi Melsec PLC Tag

For information about Mitsubishi Melsec PLC Tag configuration.

Serial Communications

For background information on serial communications.

Mitsubishi Melsec Driver

For information about the Mitsubishi Melsec Driver.

Glossary

For the meaning of terms used in Fernhill SCADA.