The FX2N-232-BD is Mitsubishi Electric’s RS-232C communication option board for the MELSEC FX2N compact PLC series, providing a second serial communication port via RS-232C point-to-point interface — enabling the FX2N base unit to communicate with a single external device (PC, barcode reader, weighing terminal, vision system, printer, or industrial instrument) on RS-232C while the built-in RS-422 port remains available for programming or HMI connection. As the standard option board for FX2N connectivity to single RS-232C devices, the FX2N-232-BD is widely installed in FX2N systems requiring direct serial device interfacing without the network topology of RS-485. Atlantech Drives holds stock of the FX2N-232-BD. Contact us for fast worldwide delivery and competitive pricing.
What Is the FX2N-232-BD?
The FX2N-232-BD is a communication option board installing in the FX2N base unit’s option board slot, providing a 9-pin D-Sub female RS-232C port for point-to-point serial communication with a single external device at distances up to 15 m. RS-232C is the standard serial interface for PC-to-device and instrument-to-instrument communication in industrial and laboratory environments — the 9-pin D-Sub connector and ±12V signal levels of the FX2N-232-BD are compatible with virtually all RS-232C-capable devices manufactured since the 1980s without level conversion or interface hardware. The board supports the same communication modes as the FX2N-485-BD in the FX2N serial communication framework — Mitsubishi FX protocol for GX Works2 programming and GOT HMI connectivity, Modbus RTU (slave) for SCADA integration, and free-protocol mode via the RS instruction for custom device communication. Unlike the FX2N-485-BD’s multi-drop RS-485 capability, the FX2N-232-BD’s RS-232C interface is strictly point-to-point — only one external device can be connected to the FX2N-232-BD’s RS-232C port, making it appropriate for dedicated single-device communication applications.
Key Technical Specifications
- Model: FX2N-232-BD
- Interface: RS-232C full-duplex, point-to-point
- Installation: FX2N base unit option board slot (direct plug-in)
- Connector: 9-pin D-Sub female (standard RS-232C pinout)
- Maximum Cable Length: 15 m
- Maximum Devices: 1 (point-to-point only)
- Baud Rate: 300 bps to 19,200 bps
- Supported Protocols: Mitsubishi FX communication protocol, Modbus RTU (slave), free-protocol (RS instruction)
- Signal Levels: ±12V RS-232C standard
- Compatible FX2N base units: All FX2N models
- Power Supply: From FX2N base unit (no external supply required)
- Operating Temperature: 0°C to 55°C
- Weight: Approx. 0.05 kg
Series Comparison & Selection Guide
The FX2N communication option board range includes three models addressing different serial communication requirements: the FX2N-485-BD (RS-485 half-duplex, up to 32 nodes, 500 m), the FX2N-232-BD (RS-232C full-duplex, point-to-point, 15 m), and the FX2N-422-BD (RS-422 full-duplex, point-to-point, 50 m). The FX2N-232-BD is the correct selection when the application requires communication with a single device that has an RS-232C serial port — PC-based SCADA systems with RS-232C serial ports, laboratory instruments, barcode readers, weighing systems, and label printers all commonly use RS-232C. The FX2N-485-BD is selected when multiple devices must communicate on the same cable (multi-drop), or when longer cable distances (above 15 m) are required. The FX2N-422-BD provides full-duplex RS-422 communication at distances up to 50 m for applications requiring better noise immunity than RS-232C over moderate distances. Only one option board can be installed on any FX2N base unit — the option board slot accommodates only a single board, so the communication type selection must match the primary communication requirement, with the other communication needs addressed by the built-in RS-422 port or by the FX2N special function module range (such as the FX2N-32DP-IF for PROFIBUS or FX2N-32CCL for CC-Link).
Maintenance Tips
The FX2N-232-BD’s 9-pin D-Sub connector is mechanically delicate compared to the screw terminal connectors on the FX2N-485-BD — inspect the connector pins annually for bent or corroded contacts, particularly in installations where the RS-232C cable is frequently connected and disconnected for laptop programming or data download. Clean corroded pins with isopropyl alcohol and a fine brush; replace the FX2N-232-BD if pins are bent beyond straightening, as bent pins cause intermittent contact that manifests as sporadic communication errors. For RS-232C cable management, secure the cable at the panel gland or cable clamp to prevent the cable weight from pulling on the D-Sub connector — unsupported cable weight causes gradual pin damage over time in installations with heavy or stiff RS-232C cables. Verify the D-Sub connector locking screws are tightened after each cable connection — unlocked D-Sub connectors with only the friction of connector mating can be disturbed by panel vibration, causing intermittent disconnection. For applications using the FX2N-232-BD for Modbus RTU SCADA communication via a PC-to-RS-232C connection, document the specific Modbus register map (D register addresses mapped to Modbus holding register numbers) in the machine documentation — this documentation is essential for SCADA system reconfiguration when the SCADA software or PC is replaced, as the Modbus mapping is defined in the FX2N program and the SCADA configuration must match it exactly.
Frequently Asked Questions
Q: Can the FX2N-232-BD connect to a modern PC without a native RS-232C port using a USB-to-RS-232C adapter?
A: Yes. USB-to-RS-232C adapters (such as those based on FTDI FT232R or Prolific PL-2303 chipsets) provide RS-232C signal levels compatible with the FX2N-232-BD on most modern PCs without native serial ports. The adapter must be installed with the manufacturer’s driver and assigned a COM port number in Windows Device Manager — then GX Works2 or the SCADA application can be configured to use the assigned COM port to communicate with the FX2N-232-BD. Note that USB-to-RS-232C adapters with Prolific PL-2303 chipsets may have driver compatibility issues with some Windows 10/11 versions — FTDI-based adapters typically provide more reliable compatibility with industrial software.
Q: What is the maximum baud rate the FX2N-232-BD supports, and is this adequate for barcode reader communication?
A: The FX2N-232-BD supports baud rates up to 19,200 bps. Most industrial barcode readers communicate at 9,600 bps standard, with some high-speed models supporting up to 115,200 bps. For barcode readers operating at 19,200 bps or below, the FX2N-232-BD provides adequate communication speed. For barcode readers requiring higher baud rates (above 19,200 bps), the FX2N-232-BD cannot accommodate the full communication speed — consider reducing the reader’s baud rate to 19,200 bps in the reader’s configuration settings if this does not affect scan performance.
Q: Does the FX2N-232-BD support hardware handshaking (RTS/CTS flow control) for communication with devices that require it?
A: The FX2N-232-BD provides a basic RS-232C implementation — the D8120 serial format register allows configuration of baud rate, data bits, stop bits, and parity, but hardware handshaking (RTS/CTS) is not natively supported by the FX2N serial communication instructions. For devices that require hardware handshaking, configure the device for software handshaking (XON/XOFF) or no handshaking if the FX2N program can manage data flow timing, or connect the device’s CTS input directly to the FX2N-232-BD’s RTS output via a loopback connection on the RS-232C cable to permanently assert CTS permission, allowing the device to receive data without hardware flow control.
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