Mitsubishi QJ71C24 Connection Guide

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5. QJ71C24 Connection Guide

Introduction

The QJ71C24 computer link module provides a serial communication link to a Mitsubishi Q-Series PLC Device. Fernhill SCADA can use this module to monitor and control a Mitsubishi Q-Series PLC Device.

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

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 Cables

RS-232 Connection

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

QJ71C24 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:

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

• 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 QJ71C24 computer link module to use the same communication options.

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:

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

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:

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

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

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

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:

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 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:

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 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 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:

Example Configuration

This table shows an example configuration for a QJ71C24 module:

The matching configuration in Fernhill SCADA would be:

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.

Fernhill SCADA Version 3.95 (20230529.2). Copyright © 2012-2023 Fernhill Software Ltd: All rights reserved.