Main Parameters and Adjustment Methods of Electromagnetic Flowmeter

1、 Main parameters of electromagnetic flowmeter
1. Measurement accuracy
Definition: Refers to the degree of closeness between a measurement result and the true value, usually expressed as a percentage.
Influencing factors: sensor design, manufacturing accuracy, signal processing algorithms, etc.
For example, the measurement accuracy of a certain electromagnetic flowmeter is ± 0.5%, which means that the error between the measured value and the actual value is within ± 0.5%.
2. Measurement range
Definition: The flow range that can be accurately measured by a flowmeter usually has two values: minimum flow and maximum flow.
Influencing factors: sensor size, structure, measurement principle, etc.
For example, the measurement range of an electromagnetic flowmeter is 0.1m ³/h-1000m ³/h, indicating that it can measure flow rates from 0.1 cubic meters per hour to 1000 cubic meters per hour.
3. Nominal diameter
Definition: The nominal diameter of a flow meter pipeline is a standardized parameter used to standardize the connection dimensions of pipeline components.
Common specifications: There are usually multiple specifications such as DN10, DN15, DN20, etc., with units in millimeters.
Selection criteria: Choose the appropriate nominal diameter based on the actual size and flow requirements of the pipeline to ensure that the flowmeter can be installed properly and measured accurately.
4. Output signal
Types: Common types include analog signals (such as 4-20mA) and digital signals (such as RS485, HART protocol, etc.).
Function: Transmit the measured flow information to the control system or other devices for monitoring, control, and data processing.
For example, 4-20mA signals can be transmitted over long distances and have strong anti-interference capabilities, making them suitable for most industrial control systems; RS485 digital signals can achieve multi-point communication and bidirectional data transmission, facilitating networking with smart devices.
5. Work pressure
Definition: The pressure range that a flow meter can withstand when operating normally.
Unit: Usually measured in megapascals (MPa) or bars.
Selection precautions: It is necessary to ensure that the working pressure of the flowmeter is greater than or equal to the actual working pressure of the pipeline system to prevent damage to the flowmeter or affect measurement accuracy due to excessive pressure.
6. Working temperature
Definition: The temperature range within which a flow meter can operate normally.
Unit: Usually measured in degrees Celsius (℃).
Considerations: It is necessary to select a suitable electromagnetic flowmeter based on the temperature of the measuring medium and the working environment to ensure its stable operation within the specified temperature range. For example, when measuring high-temperature media, it is necessary to choose a high-temperature resistant electromagnetic flowmeter.
7. Protection level
Meaning: Refers to the protective ability of the flowmeter casing against external factors such as dust and water.
Common grades: IP65, IP67, IP68, etc.
Explanation: IP65 indicates that it can prevent dust from entering and withstand the impact of low-pressure water spray; IP68 means that it can be immersed in water for a long time under a certain pressure without being affected.
8. Electrode material
Common materials: stainless steel, Hastelloy, titanium, tantalum, platinum electrodes, etc.
Selection criteria: Choose the appropriate electrode material based on the chemical properties of the measuring medium to prevent corrosion or damage to the electrode. For example, when measuring highly corrosive media, one should choose Hastelloy alloy or titanium electrodes with good corrosion resistance.
9. Lining material
Common materials: rubber (such as chloroprene rubber, polyurethane rubber, etc.), polytetrafluoroethylene (PTFE), etc.
Function: To protect the sensor, prevent corrosion and wear of the sensor by the measuring medium, and also affect the measurement performance and applicability of the flowmeter.
For example, PTFE lining has excellent corrosion resistance and is suitable for measuring various corrosive media; Rubber lining has good elasticity and wear resistance, and is suitable for measuring some general media.
2、 Adjustment method of electromagnetic flowmeter
1. Zero point adjustment
Purpose: To eliminate zero drift error of flow meters when there is no flow passing through.
Method: Usually performed after the installation of the flowmeter and when there is no flow in the pipeline.
Enter the zero adjustment function menu through the operation interface or debugging software of the flowmeter.
Follow the prompts to operate, usually to confirm that the current state is zero flow, and then start the zero adjustment program. The flowmeter will automatically calibrate and adjust the zero point.
2. Full range adjustment
Purpose: To ensure the accuracy of the flowmeter when measuring maximum flow rate.
Method: Firstly, it is necessary to determine the maximum measured flow rate value of the flowmeter.
Connect the flowmeter to a testing system with a known flow rate to achieve full range flow.
Enter the full-scale adjustment function through the operation interface or debugging software, and make corresponding adjustments based on the difference between the actual measured value and the displayed value of the flowmeter. Full scale calibration can be achieved by modifying the coefficients or parameters of the flowmeter.
3. Signal output adjustment
Purpose: To maintain an accurate correspondence between the output signal of the flowmeter and the actual flow value.
Method: For analog output signals (such as 4-20mA), signal generators or standard current sources can be used for adjustment.
Connect the flowmeter to the signal testing equipment and adjust the output parameters of the flowmeter to match the standard signal at different flow points.
For digital output signals (such as RS485), it is necessary to check and modify the format, units, and numerical accuracy of the output data through communication protocols and corresponding debugging tools.
4. Damping time adjustment
Purpose: To set an appropriate damping time to smooth the output signal of the flowmeter and reduce display instability caused by flow fluctuations.
Method: Damping time refers to the delay time of the flow meter's response to changes in flow rate.
Find the damping time setting option through the operation interface or debugging software of the flowmeter.
Gradually adjust the damping time based on the fluctuation of actual flow and the requirements for display stability. A shorter damping time can reflect flow changes more quickly, but it may cause larger fluctuations in the display; A longer damping time can make the display more stable, but it may not respond promptly to rapidly changing flow rates.
5. Frequency setting adjustment
Purpose: For some applications that require output frequency signals, it is necessary to adjust the frequency output parameters of the flowmeter to correspond with the flow value.
Method: Understand the frequency output characteristics and corresponding flow range of the flowmeter.
Enter the frequency setting function through the operation interface or debugging software.
Set appropriate frequency ranges and corresponding relationships with traffic based on actual needs and system requirements. For example, it is possible to set the frequency output corresponding to how many hertz per cubic meter.
6. Small signal cut-off adjustment
Purpose: When the flow rate is low, the flowmeter may be affected by noise and interference, resulting in significant measurement errors. By using the small signal cutoff function, the interference of these small flow signals can be eliminated.
Method: Determine the range of flow values that require small signal cutoff.
Find the option for small signal cutoff function in the settings of the flowmeter.
Set an appropriate small signal cutoff threshold based on the actual situation. When the flow rate is below the threshold, the flow meter will not display or output the flow signal to avoid small signal interference.
Technological innovation: Precision improvement: The application of new materials and continuous optimization of algorithms will enable the measurement accuracy of electromagnetic flowmeters to reach a higher level and further reduce errors.
Intelligent upgrade: With stronger intelligent processing capabilities, it can independently analyze and process data, achieve self diagnosis and fault warning.
Multi frequency excitation technology: The excitation method is developing towards multiple frequencies, enabling electromagnetic flowmeters to better adapt to complex fluid measurements and improve measurement stability and accuracy.
Application Expansion: Penetration into Emerging Industries: Widely applied in emerging fields such as biomedicine and new energy, meeting the high-precision and special requirements for flow measurement in these areas.
Deepening in the field of environmental protection: playing an important role in air pollution monitoring, soil remediation, and providing more accurate data support for environmental protection.
Integration with other technologies: Combining with artificial intelligence, cloud computing, and other technologies to achieve more efficient data management and analysis, providing strong support for industrial intelligent production.
For example, in the biopharmaceutical industry, electromagnetic flow meters can accurately measure the liquid flow rate during drug production, ensuring drug quality and production safety. With the increasing demand for environmental protection, electromagnetic flow meters will play a key role in monitoring atmospheric pollutant emissions, helping to achieve more accurate environmental governance.
In short, driven by technological innovation and application expansion, electromagnetic flowmeters have broad prospects for future development and will provide better flow measurement services for the development of various industries.