Mitsubishi PLC Analog Expansion Module FX2N-4DA

Detailed Explanation of Mitsubishi PLC Analog Expansion Module FX2N-4DA The FX2N-4DA is a 4-channel analog output special function module for Mitsubishi Electric’s MELSEC-F series PLCs. It converts the digital signals inside the PLC into standard analog voltage or current signals to control actuators such as frequency converters, control valves and servo drives. This module has been discontinued, and the FX3U-4DA is recommended as a replacement.

1. Core Specification Parameters

1. Функциональные особенности
2. Channel Independence: А 4 channels can be set to voltage or current output separately, flexibly adapting to different controlled objects
3. Selectable Digital Range: Supports unidirectional (0~10V/0~20mA) and bidirectional (-10V~+10V) output to meet different control requirements
4. Gain/Offset Adjustment: Gain and offset calibration can be performed for each channel through BFM registers to improve control accuracy
5. Fault Diagnosis: Equipped with open-circuit detection function, and fault status can be read through BFM registers
6. Совместимость: Adaptable to FX1N, FX2N, FX3G, FX3U, FX2NC, FX3GC and FX3UC series PLC hosts

III. Способ подключения

1. Basic Wiring Principle

Voltage output: Channel positive (V+) connected to load positive, Channel negative (V-) connected to load negative

Current output: Channel positive (I+) connected to load positive, Channel negative (I-) connected to load negative

The common terminal (GND) must be reliably connected to the power ground of the PLC and the load

3. 4-20mA Current Output Wiring

Set the I/O switch on the module to the current gear, and set the corresponding digital range in the program (например, 4mA corresponds to a digital value of 200, 20mA corresponds to a digital value of 1000)

1. Programming Method (Mitsubishi GX Works2/GX Developer)

The FX2N-4DA writes digital values via the TO instruction and reads status information via the FROM instruction, with parameter configuration using the Buffer Memory (BFM).

1. Module Address Setting

Special function module number: 0~7 (set according to the module connection order)

BFM addresses occupied by the module: 0~31

1. Сценарии применения
2. Process Control: Controls analog parameters such as temperature, pressure and flow, and drives actuators like electric control valves and proportional valves
3. Motion Control: Provides frequency reference signals for frequency converters to control motor speed; delivers speed or position commands to servo drives
4. Continuous Regulation: Achieves precise and continuous control of tension, speed and position in production lines such as packaging, printing and textile manufacturing
5. Hybrid System: Cooperates with analog input modules (например, FX2N-4AD) to build a complete closed-loop control system
6. Alternative Models and Notes
7. Рекомендуемые альтернативные модели

2. Replacement Notes
3. Program Modification: The BFM 0 initialization parameters of the FX3U-4DA are different from those of the FX2N-4DA, and the channel mode needs to be reset
4. Digital Range: The FX3U-4DA has a larger digital value range (0~32000), and the output value calculation method needs to be adjusted
5. Wiring Compatibility: The basic wiring method is the same, but the setting of the I/O switch of the FX3U-4DA must be confirmed

VII. Common Troubleshooting

1. No Output Signal:

Check the module power supply and extension cable connection

Confirm that the BFM 0 channel mode is set correctly

Check if the digital value is within the valid range

2. Low Output Accuracy:

Perform gain/offset calibration (via BFM 10~17)

Check if the load resistance meets the requirements

Confirm normal communication between the PLC host and the module

3. Fault Indicator Light On:

Read the BFM 20 fault status register

Check if the open-circuit detection function is enabled

Confirm the stability of the external power supply

Comparison Table of Mitsubishi FX2N-4DA and 4-Channel Analog Output Modules of Other Brands

The following is a detailed comparison of the FX2N-4DA with the same type of modules from mainstream PLC brands, including Mitsubishi’s own alternative models, corresponding products from international brands (Сименс, Omron, Шнайдер) and domestic brands (Xinje, Inovance), for reference in model selection, replacement and system integration.

1. Mitsubishi’s Own Alternative Models

1. Comparison Table of 4-Channel Analog Output Modules of Mainstream Brands

III. Key Replacement Considerations

1. Compatibility Matching

Different brands of PLCs have different expansion bus protocols, making direct physical cross-brand replacement impossible

When replacing, hardware factors such as PLC host model, number of expansion slots and power supply mode must be considered

In terms of software, the analog output program needs to be rewritten (there are significant differences in the instruction systems of different brands)

2. Functional Parameter Comparison

Resolution: The FX2N-4DA is 12-bit (including sign bit), while modern modules are generally upgraded to 14~16-bit

Conversion Speed: Increased from 10ms/channel to 2~5ms/channel, suitable for high-speed control applications

Accuracy Grade: Improved from ±1%FS to ±0.3%~±0.5%FS for more precise control

Diagnostic Functions: Modern modules generally support advanced diagnostics such as open-circuit detection and overcurrent protection

3. System Integration Suggestions

To maintain the Mitsubishi PLC system, the FX3U-4DA is the preferred replacement with minimal modifications

For cross-brand replacement, the electrical wiring and control program need to be redesigned

Modules of domestic brands (Xinje, Inovance) have high cost performance and are suitable for model selection in new projects

1. Key Points of Replacement Implementation
2. Hardware Level

Confirm that the power supply requirements (DC5V/24V) of the new module match the PLC expansion power supply

Reconnect the load circuit, paying attention to signal polarity and common terminal connection

Check if the load resistance meets the requirements of the new module (voltage output ≥1kΩ, current output ≤500Ω)

2. Software Level

Reconfigure the channel mode (voltage/current selection)

Adjust the digital value range (например, 0~32000 for FX3U-4DA, 0~1000/±2000 for FX2N-4DA)

Modify the TO/FROM instruction parameters to adapt to the BFM register structure of the new module

Add a fault diagnosis program to utilize the advanced diagnostic functions of modern modules