| Measured variable |
Direct: flow velocity; calculated: volume flow, mass flow |
| Flow velocity |
Typically 0.5 m/s ~ 5 m/s |
| Nominal diameter |
DN50 ~ DN200 |
| Turndown ratio |
10:1 |
| Current output |
(4~20) mA; internal voltage 24 VDC; load ≤750 Ω |
| Pulse output |
Width 0.1 ms ~ 2000 ms (max duty cycle 1:1); Fmax ≤5000 cp/s; coefficient 0.001~100000/unit; passive UOuter ≤30 VDC |
| Communications |
RS485; MODBUS-RTU |
| Supply voltage |
18 VDC ~ 32 VDC |
| Power consumption |
≤5 W |
| Cable entries |
M12-4 pin connector |
| Signal cable |
2 m standard; other lengths customizable |
| Accuracy |
±0.5% of measured value (flow velocity 0.5-5 m/s) |
| Repeatability |
0.16% |
| Medium temperature |
PTFE liner: -20℃ ~ 80℃ |
| Rated pressure |
1.6 MPa; high-pressure versions customizable |
| Conductivity |
≥20 μS/cm |
| Ambient/storage temperature |
-20℃ ~ 55℃ |
| Protection level |
IP65 |
The FMX400 is a compact electromagnetic flowmeter built on the Faraday electromagnetic induction principle. It directly measures the instantaneous flow rate of conductive liquids in closed pipelines and provides a totalizing (flow accumulation) function.
While delivering on-site monitoring and display, the FMX400 outputs standard current, pulse, and RS485 digital signals for recording, regulating, and control purposes — enabling fully automated monitoring and process control. It is widely used in municipal water supply, chemical processing, coal, environmental protection, light textile, metallurgy, and paper manufacturing, as well as cooling-water and make-up-water loops in data center and computing-power facilities.
* Reliable and stable measurement with high accuracy (±0.5% of measured value)
* Integrated compact design with no moving parts — easy installation and virtually maintenance-free operation
* RS485 communication interface supporting the Modbus RTU protocol
* Bidirectional flow measurement — accurately measures both forward and reverse flow
* Advanced low-frequency square-wave excitation: excellent zero stability, strong immunity to interference, reliable operation
* Adjustable meter orientation and display interface for convenient reading in various installation positions
* Built-in Chinese and English interface with freely selectable language
* 10:1 turndown ratio; repeatability 0.16%
As a core flow instrument for the computing-power industry chain, the FMX400 monitors conductive cooling water and make-up water in data center chilled-water systems, where stable, maintenance-free measurement and Modbus RTU integration into BMS/DCS platforms are essential.
The FMX400 is also widely used in:
- Municipal water supply
- Chemical processing
- Coal industry
- Environmental protection
- Light textile
- Metallurgy
- Paper manufacturing
For any conductive liquid (conductivity ≥20 μS/cm) in a closed pipeline, within a medium temperature of -20℃ to 80℃ (PTFE liner) and rated pressure of 1.6 MPa.
The electromagnetic flowmeter employs an advanced low-frequency square-wave excitation design, and its operating principle is based on Faraday’s law of electromagnetic induction. As shown in Figure 1, two electromagnetic coils located at the upper and lower sides generate a constant or alternating magnetic field.When a conductive fluid flows through the flowmeter, an induced electromotive force (EMF) is generated between the two electrodes mounted on opposite sides of1 Introduction the meter tube wall.
The magnitude of this induced EMF is proportional to: the flow velocity of the conductive medium, the magnetic flux density of the magnetic field, and the effective conductor width (i.e., the inner diameter of the flowmeter measuring tube).By processing this induced voltage signal, the flow rate of the medium can be calculated. The induced EMF can be expressed as:
(EMF: Induced electromotive force equation)
E=K×B×V×D
Where:
E－Induced electromotive force
K－Meter constant
B－Magnetic induction density
V－Average flow speed in the cross-section of the measuring tube
D－Inner diameter of measuring tube
When measuring the flow, the fluid flows through a magnetic field that is perpendicular to the flow direction. The flow of conductive fluid induces a potential proportional to the average flow velocity, thus requiring the conductivity of the measured flowing liquid to be higher than the minimum conductivity. The induced voltage signal is detected by two electrodes and transmitted to the converter via a cable. After a series of analog and digital signal processing, the accumulated flow and real-time flow are displayed on the converter screen.
Q：What liquids can the FMX400 electromagnetic flowmeter measure?
The FMX400 measures conductive liquids in closed pipelines with a conductivity of ≥20 μS/cm, at medium temperatures of -20℃ to 80℃ (PTFE liner) and a rated pressure of 1.6 MPa (high-pressure versions customizable). Typical media include water, cooling water, and process liquids.
Q：What pipe sizes are available?
The FMX400 covers nominal diameters from DN50 to DN200. Flow ranges span 3.5-35 m³/h (DN50) up to 56-560 m³/h (DN200).
Q：Does the FMX400 support reverse flow measurement?
Yes. Bidirectional flow measurement accurately measures both forward and reverse flow, with separate forward, reverse, and net accumulation totals.
Q：Is the FMX400 suitable for outdoor installation?
Yes, the protection level is IP65, with an ambient/storage temperature range of -20℃ to 55℃. The housing is 304 stainless steel, the sensor is 316L SS, and the liner is PTFE.
Q：Does it detect empty pipes?
Yes. The empty pipe alarm function can be enabled, triggering when the liquid does not fully fill the pipe or the sensor is abnormally grounded. The alarm threshold is user-configurable.
Q：How is the flowmeter installed?
The compact integrated design has no moving parts, ensuring easy installation and virtually maintenance-free operation. For reference accuracy, an inlet run ≥10 DN and outlet run ≥5 DN is recommended. Clamp (ISO 2852) and flange (JB/T 81-2015, PN16) connections are available.
Q：Is the FMX400 suitable for data center cooling water monitoring?
Yes. For conductive chilled and cooling water loops in data centers, the FMX400 provides stable ±0.5% accuracy measurement with RS485 Modbus RTU integration into BMS/DCS platforms, plus IP65 protection for plant-room environments.
