QJ71C24N-R2 2-Channel RS-232 Serial Communication Module | Mitsubishi Electric

The Original New Mitsubishi Electric QJ71C24N-R2 is a 2-channel RS-232 serial communication module for the MELSEC-Q series programmable controllers. It provides two independent RS-232 (D-sub 9-pin) interfaces, enabling connection to two third-party serial devices simultaneously — such as personal computers, HMI panels, barcode readers, measurement devices, and printers. Supporting transmission speeds up to 230.4 kbps (CH1 only) and multiple communication protocols including MC protocol, non-procedural protocol, bidirectional protocol, and predefined protocol, the module delivers flexible, high-speed serial connectivity for factory automation and process control systems. It occupies 32 I/O points and draws 0.26 A from the 5 V DC backplane bus.

Core Engineering Highlights:
2 x RS-232 (D-sub 9-pin) interfaces | Up to 230.4 kbps transmission speed (CH1) | Max. transmission distance 15 m | Full-duplex / half-duplex communication | MC protocol, non-procedural, bidirectional, predefined protocol support | 32 occupied I/O points | 0.26 A @ 5 V DC internal current consumption | 98 × 27.4 × 90 mm | 0.20 kg

Key Features:

• Original New Mitsubishi Electric QJ71C24N-R2 module

• 2 independent RS-232 channels for connecting two third-party serial devices simultaneously

• Transmission speeds from 50 bps to 230.4 kbps (230.4 kbps available on CH1 only)

• Total transmission speed of two interfaces: up to 230.4 kbps

• Total transmission speed: up to 115.2 kbps when communication data monitoring function is used

• Supports MC protocol (MELSEC communication protocol) for external device read/write access to QCPU device memory

• Supports non-procedural protocol for communication with intelligent devices using native protocols

• Supports bidirectional protocol and predefined protocol (up to 128 protocols per module)

• MELSOFT engineering software can establish connection to the PLC CPU through serial connection for programming and maintenance

• Remote password function prevents unauthorized access to programmable controllers via modem line

• Data format configurable: start bits (1), data bits (7/8), parity (odd/even/none), stop bits (1/2)

• RS-232 transmission control: DTR/DSR, RS/CS, CD (DCD) signal control, DC1/DC3 (Xon/Xoff), DC2/DC4

• Line configuration: 1:1 connection

• Error detection: parity check and sum check code

Applications:

• Connecting personal computers and HMI panels to MELSEC-Q series PLC systems

• Barcode reader and measurement device integration via serial communication

• Remote programming and maintenance via modem line using MELSOFT software

• Printer and marquee display connection for data logging and reporting

• Factory automation and process control serial device networking

Technical Specifications:

System Compatibility:

• Compatible with Mitsubishi Electric MELSEC-Q series programmable controllers. Module compatibility should be verified before installation.

• Supports Q series CPU modules (Q00J, Q00, Q01, Qn, QnH, QnPH, QnPRH, QnU series)

• Configuration performed using GX Works2 or GX Developer engineering software

• Predefined protocol support (up to 128 protocols) requires module function version B with serial number first 5 digits 11062 or higher

• Compatible with MODBUS® and BACnet® predefined protocol libraries

Related Products:

• QJ71C24N – 1 x RS-232 + 1 x RS-422/485 serial communication module

• QJ71C24N-R4 – 2 x RS-422/485 serial communication module

• QJ71E71-100 – Ethernet interface module for MELSEC-Q series

• QJ71MT91 – MODBUS/TCP interface module

• GX Works2 – Programming and configuration software

• Q38B – 8-slot main base unit for Q series

PLC ERA is an independent industrial automation distributor supplying genuine Original New products through established global supply channels. All products are factory sealed when applicable and undergo quality inspection prior to shipment. Mitsubishi Electric and MELSEC are trademarks of Mitsubishi Electric Corporation.