Mitsubishi QJ71C24 Setup Guide

Help Contents

Introduction

The QJ71C24 computer link module provides a serial communication link to a Mitsubishi Q-Series PLC. Applications, such as Fernhill SCADA, can use the module to monitor and control a Mitsubishi Q-Series PLC.

The information in this guide applies to a range of Mitsubishi Melsec Q-Series serial communication modules:

ModuleInterface
QJ71C24Dual RS-232 ports
QJ71C24NDual RS-232 ports
QJ71C24-R2One RS-232 and one RS422/485 port
QJ71C24N-R2One RS-232 and one RS422/485 port
QJ71C24-R4Two RS422/485 ports
QJ71C24N-R4Two RS422/485 ports

The rest of this article uses the name QJ71C24 to refer to any of the above modules.

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

Connection TypeDescription
RS-232 DE-09RS-232 using a D-Subminiature 9 pin female connector
RS-422/485 Screw TerminalsRS-422/485 using screw terminals

Connection Cables

The RS-232 port on a QJ71C24 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 QJ71C24 to a PC, a connection cable with this wiring is required:

QJ71C24 RS-232
D-Subminiature connector DE-09 plug wiring side shown
PC
D-Subminiature connector DE-09 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.

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 a QJ71C24 module, both need use the same communication options. There are a two main ways to achieve this:

Manual Configuration

The QJ71C24 module has two communication ports labelled Ch 1 and Ch 2. The communications settings of each port are configured by writing values to the switch settings of the module.

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

Configuring the QJ71C24 Module using GX Developer

You can use GX Developer to set the switch settings of the QJ71C24 module. Writing values to the switch settings will configure the communication parameters of the QJ71C24 module. To configure a QJ71C24 module:

1. Open a project in GX Developer and expand the Parameter branch of the project:

Q-Series Project Loaded in GX Developer

2. Double click the PLC Parameter branch to open the Parameter window. Select the I/O assignment tab:

Parameter Window

Note: The actual contents of the I/O Assignment table will depend on the module(s) fitted.

3. Click on the Switch Setting button. The Switch setting for I/O and intelligent function module dialog opens:

Switch setting for I/O and intelligent function module

4. Enter appropriate values for the settings Switch 1 to Switch 5. The following section describes how the switch settings map to the Mode property of the Mitsubishi Melsec serial channel.

Mapping QJ71C24 Switch Settings to Fernhill SCADA Mode and StationNumber Properties

The QJ71C24 switch settings consist of five 16-bit word values labelled as: Switch 1 to Switch 5.

Switch 1 to Switch 4 define the communication settings of Ch 1 and Ch 2. Switch 1 to 4 should be configured as:

Ch 1Ch 2DescriptionComment
Switch 1 Bit 0Switch 3 bit 0Independent PortsMust be off for Ch 1
Can be on or off for Ch 2
Switch 1 bit 1Switch 3 bit 1Data BitsShould match the Mode property
Switch 1 bits 2-3Switch 3 bits 2-3ParityShould match the Mode property
Switch 1 bit 4Switch 3 bit 4Stop BitsShould match the Mode property
Switch 1 Bit 5Switch 3 bit 5Sum CheckMust be set to On
Switch 1 Bit 6Switch 3 bit 6Controls in Run ModeMust be set to On
to allow controls from Fernhill SCADA
Switch 1 Bit 7Switch 3 bit 7Allow configurationCan be set to On or Off
Switch 1 bits 8-15Switch 3 bits 8-15Baud RateShould match the Mode property
Switch 2Switch 4Frame FormatShould match the CommFormat property

Switch 5 defines the station number of the QJ71C24. The value of the Switch 5 must match the value of the StationNumber property of the Mitsubishi Melsec PLC Tag.

Switch 1/3 Bit 1 - Data Bits

Bit 1 of switch 1 defines the number of data bits in each character transmitted on Ch 1. Bit 1 of switch 3 defines the number of data bits in each character transmitted on Ch 2. The Mode property of the Mitsubishi Melsec serial channel should contain a matching Data clause:

Switch 1/3 Bit 1Mode String Clause
OffData=7
OnData=8

Switch 1/3 Bits 2-3 - Parity

Bits 8-15 of switch 1 define the parity bits added to each character transmitted on Ch 1. Bits 8-15 of switch 3 define the parity bits added to each character transmitted on Ch 2. The Mode property of the Mitsubishi Melsec serial channel should contain a matching Parity clause:

Switch 1/3 Bit 2Switch 1/3 Bit 3Mode String Clause
Off*Parity=N
OnOffParity=O
OnOnParity=E

Note: The asterisk (*) means not applicable.

Switch 1/3 Bit 4 - Stop Bits

Bit 4 of switch 1 defines the number of stop bits in each character transmitted on Ch 1. Bit 4 of switch 3 defines the number of stop bits in each character transmitted on Ch 2. The Mode property of the Mitsubishi Melsec serial channel should contain a matching Stop clause:

Switch 1/3 Bit 4Mode String Clause
OffStop=1
OnStop=2

Switch 1/3 Bits 8-15 - Baud Rate

Bits 8-15 of switch 1 define the baud rate of Ch 1. Bits 8-15 of switch 3 define the baud rate of Ch 2. The Mode property of the Mitsubishi Melsec serial channel should contain a matching Baud clause:

Switch 1/3 Bits 8-15Mode String Clause
00hBaud=300
01hBaud=600
02hBaud=1200
03hBaud=2400
04hBaud=4800
05hBaud=9600
07hBaud=19200
09hBaud=38400
0AhBaud=57600
0BhBaud=115200

Switch 2/4 - Communication Protocol

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:

Switch 2/4CommFormat
1Format 1
2Format 2
3Format 3
4Format 4

Example Configuration

This table shows an example configuration for a QJ71C24 module:

Switch 1Switch 2Switch 3Switch 4Switch 5
077C0001056600020005

The matching configuration in Fernhill SCADA would be:

ParameterCh 1Ch 2
Channel ModeBaud=19200 Data=7 Parity=E Stop=2Baud=9600 Data=8 Parity=O Stop=1
Channel CommFormatFormat 1Format 2
Device StationNumber55

For more information refer to the QJ71C24 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 device configuration.

Serial Communications

For background information on serial communications.

Fernhill SCADA Drivers

For information about other drivers available in Fernhill SCADA.

Glossary

For the meaning of terms used in Fernhill SCADA.