An ultrasonic flow meter is an instrument that measures flow rate by utilizing the time difference in the propagation of ultrasonic waves through a fluid. Below is an interpretation of the ultrasonic flowmeter user manual and an operation guide:

1. Product Overview and Measurement Principle

Product Overview

The ultrasonic flowmeter is suitable for measuring liquid flow, featuring non-contact measurement that does not interfere with the fluid flow state.

Measurement Principle

When an ultrasonic wave propagates through the liquid, the fluid flow causes a slight change in the transmission time.

  • The change in propagation time is proportional to the fluid flow velocity.
  • At zero flow, the time required for the two sensors to emit and receive the sound wave is identical.
  • When the liquid is flowing, the transmission time for sound waves propagating against the flow is longer than that for waves propagating with the flow.

2. Installation and Measurement

Unpacking Inspection

  • Verify that the spare parts match the packing list.
  • Inspect the casing for any damage during transport, check for loose screws, and ensure all connections are secure.

Wiring Diagram

  • Refer to the model-specific wiring diagram to connect the wiring appropriately.

Keyboard Operation

  • Use the numeric keys to input numbers or menu selections.
  • Use specific keys for functions like backspace, delete, or accessing the menu.
  • Press the Enter key to confirm entered numbers or selected options.

Quick Parameter Input

  • Input parameters such as pipe outer diameter, pipe wall thickness, pipe material, lining material (if applicable), liquid type, sensor type, and installation method.
  • Follow the sequence to enter or select the relevant parameters.

Selecting the Installation Measurement Point

  • Choose a straight pipe section with uniform fluid distribution for the installation point.
  • Avoid installation near valves, pumps, high voltage electrical sources, and variable frequency drives, as these may cause interference.
  • Ensure that the temperature and pressure at the installation point are within the sensor’s working range.

Sensor Installation

  • Choose the appropriate installation method (e.g., V-method or Z-method) based on the pipe material and installation type.
  • Apply ultrasonic coupling agent on the pipe surface, then securely attach and fasten the sensor.
  • Adjust the sensor’s installation distance and angle to ensure optimal signal quality and measurement accuracy.

3. Operation and Maintenance

Setting Common Parameters

  • Set the display window and measurement units according to the reading needs.
  • Set parameters such as damping coefficient, calibration date, and time.

Signal Quality and Time Ratio

  • Adjust the sensor to maximize signal strength and quality.
  • Check the transmission time ratio to ensure it is between 97% and 103%, which verifies the consistency of the measurement parameters with the sensor installation distance.

Wiring and Grounding

  • The ultrasonic-specific cable between the main unit and sensor should be as short as possible, with a maximum length of 200 meters.
  • Wiring should be neatly organized in conduits or cable channels.
  • Avoid running cables in parallel with power or high-voltage cables.
  • The main unit should be grounded for safety.

Communication Interface and Protocol

  • The ultrasonic flowmeter features an isolated RS485 interface and supports various communication protocols (e.g., MODBUS).
  • It can be connected to a PROFIBUS network via a MODBUS-PROFIBUS converter.
  • A GPRS communication module can be used to read data via the RS-485 bus and transmit it over the internet.

Common Issues and Troubleshooting

  • If the flow reading shows a negative value, check if the low-flow cutoff value is set correctly.
  • If the flowmeter displays non-zero instantaneous flow when the pipeline is filled with still water, perform a zeroing operation using the zero menu.
  • After prolonged use, you may need to adjust coefficients (scaling factors) for error correction.

Conclusion

The ultrasonic flowmeter is easy to operate, provides accurate measurements, and features non-contact measurement. When using it, carefully read the user manual and follow the guidelines for installation, measurement, and maintenance to ensure optimal performance.

If you want to know more about the flow meter or flow meter selection, please consult the Aister flow meter manufacturer email: sales@aistermeter.com for help.