FMU44 Ultrasonic Level Meter Overview
FMU44 ultrasonic level meter is a non-contact level measuring instrument, widely used for level monitoring in water treatment, chemical, petroleum, and other industries. It uses the ultrasonic echo ranging principle to achieve continuous measurement of liquid height. This article provides the official Chinese manual download and includes an analysis of technical key points.
Click to download: FMU44 Ultrasonic Level Meter Chinese Manual.pdf
Working Principle and Core Advantages
Ultrasonic Ranging Principle
The FMU44 probe emits high-frequency ultrasonic pulses, and after the sound waves reflect off the liquid surface, they are received by the same probe. The instrument calculates the time difference between transmission and reception and combines it with the speed of sound to obtain the liquid level height. This principle is not affected by medium density, conductivity, etc.
Main Technical Advantages
- Non-contact measurement: Avoids corrosion and adhesion, suitable for sewage and acid-base liquids.
- High precision: Typical accuracy can reach ±0.2% FS, meeting industrial process control.
- Wide range: Maximum range can reach 15 meters, adapting to various tanks.
- Easy installation: Threaded or flanged connection, supports top installation.
Key Technical Parameters
The table below lists typical parameters of the FMU44 for selection reference. For specific values, please refer to the manual.
| Parameter | Specification |
|---|---|
| Measuring range | 0.5 ~ 15 m |
| Accuracy | ±0.2% FS |
| Resolution | 1 mm |
| Output signal | 4-20 mA / HART / RS485 |
| Power supply | 24 VDC |
| Protection class | IP67 |
| Process temperature | -40 ~ 80 °C |
| Process pressure | -0.2 ~ 0.1 MPa |
Installation and Commissioning Steps
Installation Precautions
- Ensure the probe is perpendicular to the liquid surface to avoid weakened echoes caused by tilting.
- The installation location should be away from interference sources such as feed inlets and agitators.
- Reserve the blind zone distance, usually 0.3~0.5 meters.
Commissioning Process
- After power-on, check whether the instrument display is normal.
- Set the empty tank height and full tank height, corresponding to 4 mA and 20 mA output.
- Adjust sound velocity compensation or filtering parameters according to medium characteristics.
- Observe the echo curve to ensure stable signal.
- Record commissioning parameters and complete calibration.
Common Problems and Maintenance
Troubleshooting
- No echo: Check whether the probe is scaled and whether the liquid surface fluctuates severely.
- Measurement deviation: Recalibrate or check the sound velocity setting.
- Abnormal output: Confirm whether the power supply and load resistance match.
Daily Maintenance
Regularly clean the probe surface to avoid dust or condensate affecting sound wave transmission. It is recommended to check the seal and cable connection every six months. After long-term shutdown, recalibration is required before restarting.
Selection and Procurement Suggestions
When purchasing the FMU44, please confirm the process connection, range, output signal, and medium temperature. If measuring corrosive liquids, a PTFE probe can be selected. For foam or steam environments, it is recommended to choose a model with a waveguide tube. Downloading the complete manual provides detailed dimensions and certification information.
Download link provided again: FMU44 Ultrasonic Level Meter Chinese Manual.pdf