Mitsubishi A(1S)J71QC24(N) Connection Guide

Introduction

The A(1S)J71QC24(N) computer link module provides a serial communication link to a Mitsubishi QnA Series PLC Device. Fernhill SCADA can use this module to monitor and control a Mitsubishi QnA Series PLC Device.

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

Module	Interface
AJ71QC24	One RS-232 plus one RS-422/485
AJ71QC24-R2	Two RS-232
AJ71QC24-R4	One RS-422 plus one RS-422/485
AJ71QC24N	One RS-232 plus one RS-422/485
AJ71QC24N-R2	Two RS-232
AJ71QC24N-R4	One RS-422 plus one RS-422/485
A1SJ71QC24	One RS-232 plus one RS-422/485
A1SJ71QC24-R2	Two RS-232

The rest of this article uses the name AJ71QC24 to refer to any of the above modules.

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

Connection Type	Description
RS-232 DE-9	RS-232 using a D-Subminiature 9 pin female connector
RS-422/485 Screw Terminals	RS-422/485 using a screw terminals

Connection Cables

RS-232 Connection

The RS-232 port on an AJ71QC24 can connect directly to a serial port on a PC. The serial port on a PC is usually a 9 pin D-subminiature connector. To connect the AJ71QC24 to a PC, a connection cable with this wiring is required:

AJ71QC24 RS-232		PC
RXD	2	3	TXD
TXD	3	2	RXD
DTR	4	6	DSR
GND	5	5	GND
DSR + DCD	6 + 1	4	DTR
RTS	7	8	CTS
CTS	8	7	RTS

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:

Baud Rate
Frame Format
Protocol

For Fernhill SCADA to communicate with an AJ71QC24 module, both need to use the same communication options. There are two main ways to achieve this:

The easiest way is to use the Mitsubishi Melsec Serial Autodetect Wizard. Using the options you select, the wizard will try different settings to work out the correct Fernhill SCADA configuration.
Manually configure Fernhill SCADA and the AJ71QC24 module to use the same communication options.

Manual Configuration

The AJ71QC24 module is configured by front panel switches.

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

The Mode and CommFormat properties on the Mitsubishi Melsec serial channel.
The StationNumber property on the Mitsubishi Melsec PLC Tag.

The relationship between AJ71QC24 front panel switches and Fernhill SCADA properties is:

Switch	Fernhill SCADA Property
Station No	StationNumber in the Mitsubishi Melsec PLC Tag
Mode	CommFormat in the Mitsubishi Melsec serial channel
SW2-SW5, SW9-SW12	Mode in the Mitsubishi Melsec serial channel

These switches on the AJ71QC24 Computer Link module should be set to these positions for correct operation:

AJ71QC24 Switch	Setting
SW6	On (Use sum check)
SW7	On (Allow write during RUN)

Station No

The StationNumber property of the Mitsubishi Melsec PLC Tag should match the Station No switch on the module front panel.

Mode Switch

Fernhill SCADA supports communication modes 1, 2, 3, and 4. The CommFormat property of the Mitsubishi Melsec serial channel should be set to the matching value:

Mode Switch	CommFormat
1	Format 1
2	Format 2
3	Format 3
4	Format 4

Note: The AJ71QC24, AJ71QC24-R2, and AJ71QC24-R4 modules only support Format 1.

SW2

SW2 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:

SW2	Mode String Clause
Off	Data=7
On	Data=8

SW3 and SW4

SW3 and SW4 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:

SW3	SW4	Mode String Clause
Off	*	Parity=N
On	Off	Parity=O
On	On	Parity=E

Note: The asterisk (*) means not applicable.

SW5

SW5 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:

SW5	Mode String Clause
Off	Stop=1
On	Stop=2

SW9 to SW11

SW9 to SW11 define the baud rate of the communication channel. The Mode property of the Mitsubishi Melsec serial channel should contain a matching Baud clause:

SW9	SW10	SW11	SW12	Mode String Clause
Off	Off	Off	Off	Baud=300
On	Off	Off	Off	Baud=600
Off	On	Off	Off	Baud=1200
On	On	Off	Off	Baud=2400
Off	Off	On	Off	Baud=4800
On	Off	On	Off	Baud=9600
Off	On	On	Off	Baud=19200
On	On	On	Off	Baud=38400
Off	Off	Off	On	Baud=14400
On	Off	Off	On	Baud=28800
Off	On	Off	On	Baud=57600
On	On	Off	On	Baud=115200