NKFD-M Digital Mass Flow Meter Controller — Medium Flow Range

Product Series: NKFD-M
Product Name: Digital Mass Flow Meter / Controller
Product Types: NKFD-MM Mass Flow Meter / NKFD-MC Mass Flow Controller

Direct Answer

The NKFD Digital Mass Flow Meter / Controller (Medium Flow Range) is a thermal mass flow instrument designed for gas flow measurement and control in medium-flow applications. The NKFD-M series uses a thermal measurement principle and provides fast response, high measurement accuracy, digital communication, and multiple analog signal options.

According to the supplied product specifications, the medium-flow NKFD-M series covers flow ranges from 30 SLM to 300 SLM. The series includes NKFD-MM Mass Flow Meter for gas mass flow measurement and NKFD-MC Mass Flow Controller for measurement and closed-loop flow control.

---

Key Takeaways

• Thermal mass flow measurement principle with fast response and high accuracy.
• Medium flow range from 30 SLM to 300 SLM.
• NKFD-MM is designed for mass flow measurement.
• NKFD-MC combines mass flow measurement with automatic flow control.
• Mass flow meter range ratio: 100:1.
• Controller valve control range: 50:1.
• Accuracy: ±1.0% F.S.
• Linearity: ±0.5% F.S.
• Repeatability: ±0.2% F.S.
• Supports 0–5 VDC, 1–5 VDC and 4–20 mA signal options.
• Supports RS232 / RS485 and MODBUS communication.
• Available with different pressure ratings, display options, sealing materials, and process connections.

---

What Is the NKFD Medium-Flow Mass Flow Meter / Controller?

The NKFD-M series Digital Mass Flow Meter / Controller is designed for measuring and controlling the mass flow of gases in medium-flow applications.

The instrument consists of a thermal mass flow sensor, flow measurement electronics, and, in the controller version, a control valve and associated control circuit.

The thermal sensor detects the heat-transfer characteristics associated with the flowing gas and generates a corresponding flow signal.

The series is available in two configurations:

NKFD-MM Mass Flow Meter

The NKFD-MM is designed primarily for gas mass flow measurement. Depending on the selected configuration, it can provide local digital display, analog output, and digital communication.

NKFD-MC Mass Flow Controller

The NKFD-MC combines gas mass flow measurement and automatic flow control. The measured flow signal is compared with the preset value, and the controller regulates the control valve according to the deviation between the measured flow and the setpoint.

---

How Does the NKFD Mass Flow Meter Work?

The NKFD-M series operates according to the thermal mass flow measurement principle.

When gas passes through the sensing section, the flowing gas affects the heat transfer around the thermal sensing elements. The resulting thermal change is detected by the sensor and converted into an electrical signal representing the gas flow.

For the NKFD-MC Mass Flow Controller, the measured flow signal is processed and compared with the preset control signal. The resulting deviation is used to drive the control valve, forming a closed-loop flow control process.

Basic Measurement Process

Gas Flow → Thermal Sensor → Flow Signal → Signal Processing → Flow Display / Output

Controller Process

Gas Flow → Thermal Sensor → Flow Measurement → Setpoint Comparison → Control Valve → Flow Regulation

This design allows the NKFD-MC to perform both flow measurement and automatic flow regulation.

---

NKFD-M Series Technical Specifications

The following specifications are based on the supplied product data.

Note: Pressure rating, power supply, sealing material, process connection, display, and signal configuration are selected according to the model code. Please confirm the final technical configuration before ordering.

---

Available Flow Ranges

The NKFD-M medium-flow series provides multiple flow-range options:

• 30 SLM
• 40 SLM
• 50 SLM
• 60 SLM
• 70 SLM
• 80 SLM
• 90 SLM
• 100 SLM
• 150 SLM
• 200 SLM
• 250 SLM
• 300 SLM

The specific flow range should be selected according to the actual gas flow requirements of the application.

---

NKFD-M Product Selection

The NKFD-M series uses a model coding system for configuration selection.

1. Series

NKFD-M

2. Product Type

• C — Mass Flow Controller
• M — Mass Flow Meter

3. Pressure Rating

• M — 3 MPa
• Z — 10 MPa, for the mass flow meter configuration

4. Local Display

• N — Without LCD display
• X — With LCD display

5. Flow Range

The selection table provides:

30 / 40 / 50 / 60 / 70 / 80 / 90 / 100 / 150 / 200 / 250 / 300 SLM

6. Flow Input Signal

• 0–5 VDC
• 4–20 mA
• 1–5 VDC

7. Output Signal

• 0–5 VDC
• 4–20 mA
• 1–5 VDC

8. Power Supply

• ±15 VDC
• 24 VDC

9. Communication

• RS485
• RS232

10. Seal Material

Options shown in the supplied selection table include:

• Fluororubber
• PTFE
• Nitrile rubber
• Other

11. Process Connection

Available connection options shown in the product data include:

• φ3
• φ6
• 1/8″
• 1/4″
• Other options available upon consultation

---

How to Select the NKFD Medium-Flow Mass Flow Meter / Controller?

Proper selection should be based on the actual gas and operating conditions.

1. Determine the Gas Flow Range

Identify the minimum, normal, and maximum required flow rates.

The NKFD-M series provides multiple flow ranges from 30 SLM to 300 SLM, allowing the instrument to be matched to different medium-flow gas applications.

2. Select Meter or Controller

Choose NKFD-MM Mass Flow Meter when the primary requirement is gas mass flow measurement.

Choose NKFD-MC Mass Flow Controller when the system requires both measurement and automatic flow regulation according to a setpoint.

3. Confirm Operating Pressure

For the controller configuration, the supplied specifications indicate an operating differential pressure of 0.1–0.5 MPa.

For the mass flow meter, the specified pressure drop is less than 0.01 MPa.

The applicable pressure rating should also be selected according to the model configuration.

4. Select the Signal Type

The NKFD-M series provides several electrical signal options:

• 0–5 VDC
• 1–5 VDC
• 4–20 mA

The selected signal should be compatible with the connected PLC, controller, data acquisition system, or other equipment.

5. Select the Communication Interface

For digital communication and system integration, the product provides:

• RS232
• RS485
• MODBUS protocol

The communication option should be selected according to the requirements of the host control or monitoring system.

6. Confirm Process Connection

The connection should match the gas piping and equipment interface.

Available options shown in the product information include:

φ3, φ6, 1/8″, 1/4″, and other connection configurations.

---

NKFD-M Applications

According to the supplied product information, the NKFD-M series can be applied in a variety of industrial and laboratory gas-flow applications, including:

• Vacuum systems
• Coating processes
• Solar energy
• Semiconductor applications
• Petrochemical processes
• Coal and metallurgy
• Gas generation and gas distribution
• Environmental protection
• Instrument analysis

The product is particularly applicable where medium-range gas flow measurement, monitoring, or closed-loop flow control is required.

---

NKFD-MM vs. NKFD-MC

---

Frequently Asked Questions

1. What type of gas flow does the NKFD-M measure?

The NKFD-M is a thermal mass flow instrument for gas flow measurement and control. The applicable gas and calibration conditions should be confirmed according to the specific application and model.

2. What is the flow range of the NKFD-M series?

The product selection table provides flow ranges from 30 SLM to 300 SLM, including 30, 40, 50, 60, 70, 80, 90, 100, 150, 200, 250, and 300 SLM.

3. What is the difference between NKFD-MM and NKFD-MC?

The NKFD-MM is a mass flow meter for flow measurement.

The NKFD-MC is a mass flow controller that combines flow measurement with automatic regulation through a control valve.

4. Does the NKFD-M support 4–20 mA?

Yes. 4–20 mA is one of the available analog signal options. The product also provides 0–5 VDC and 1–5 VDC options.

5. Does the NKFD-M support RS485 and MODBUS?

Yes. The supplied product specifications list RS232, RS485, and MODBUS protocol options.

6. What is the response time?

According to the supplied technical data:

• NKFD-MC: <2 s
• NKFD-MM: <0.8 s

7. What is the accuracy of the NKFD-M series?

The supplied specification indicates an accuracy of ±1.0% F.S., with ±0.5% F.S. linearity and ±0.2% F.S. repeatability.

---

Conclusion

The NKFD Digital Mass Flow Meter / Controller (Medium Flow Range) is a thermal mass flow instrument designed for medium-range gas flow measurement and control.

The series provides flow ranges from 30 SLM to 300 SLM and includes two main configurations: NKFD-MM Mass Flow Meter for gas flow measurement and NKFD-MC Mass Flow Controller for measurement and closed-loop flow regulation.

With ±1.0% F.S. accuracy, multiple analog signal options, RS232/RS485 communication, and MODBUS protocol, the NKFD-M series can be integrated into a range of gas measurement and control systems.

For correct product selection, users should confirm the gas medium, flow range, operating pressure, differential pressure, accuracy requirements, signal type, power supply, communication method, seal material, and process connection before ordering.

For detailed specifications and model selection, please contact NOIKE-AH staff for consultation.