Positive displacement flow meter with 4-20mA output

What is a positive displacement flow meter?

A positive displacement flow meter, also known as a volumetric flowmeter, is a precision liquid flow measurement instrument. Its working principle is very direct: it divides the fluid into "small units" of known volume, and calculates the total fluid volume by counting the number of these units. It's like using a fixed capacity bucket to measure the total amount of liquid flowing through the pipeline bucket by bucket. Common types of flow meters include oval gear flow meters, roots flow meter and helical gear flow meter.

Positive Displacement flow meter wide applicable scenarios

Due to its high-precision characteristics, PD flow meters are often used in situations that require precise measurement, settlement, or batch control. Typical applications include:

• Oil trade: such as gas stations, transportation of diesel, fuel, kerosene, propane, jet fuel, crude oil and refined oil products.
• Chemical industry: Accurately adding expensive or critical chemical reagents, such as toluene, xylem, naphtha, paraffin
• Food and pharmaceuticals: measuring raw materials such as edible oil, alcohol, ethanol, molasses, syrup, etc.
• Measurement of high viscosity fluids such as resins, crude oi and asphalt.

Why do we need a 4-20mA output positive displacement flowmeter?

• Traditional mechanical PD flow meters mainly provide cumulative flow (total usage) without any outputs. Silverinstruments.com can supply the models equipped with 4-20mA output function bring key modernization advantages:
• Realize remote monitoring of instantaneous flow rate: 4-20mA signal can seamlessly correspond to the instantaneous flow rate value of the fluid. This allows operators to monitor the flow rate changes in the pipeline in real-time in the central control room, greatly improving the convenience of process control.
• Easy integration and automation: 4-20mA analog output is the most standard signal in the field of industrial control, which can be easily received by systems such as PLC and DCS. This enables flow data to directly participate in automated control, such as automatically adjusting valves, triggering alarms, or interlocking with other equipment.
• Enhancing data value: By simultaneously obtaining instantaneous flow (4-20mA current output) and cumulative flow (displayed by the instrument itself), enterprises can conduct more comprehensive energy efficiency analysis, process optimization, and fault diagnosis.

Features of 4-20mA analog Output Transmitter for PD flow meter

·         1. Four-wire system (positive power wire, 4-20mA current wire, pulse signal wire, power ground wire)

·            Note: For 4-20mA output only, it is a three-wire system. The pulse signal wire is not externally connected during delivery.

·         2. Direct 4-20mA output from flow meter, long transmission distance, safe and reliable

Technical Parameters of 4-20mA transmitters for PD flow meter

1. Output signals:

a. Analog quantity 4-20mA

b. Voltage pulse: VL<0.5V, VH>9V for 12V supply; VL<1V, VH>20V for 24V supply

2. Allowable error:

• Analog quantity: ±0.5% FS

• Pulse quantity: ±1 pulse

3. Ambient temperature: -25°C to +50°C

4. Analog quantity load resistance (user end):

• <400Ω for 12V supply

• <800Ω for 24V supply

5. Power supply:

• DC12V ± 10%, 60mA

• DC24V ± 10%, 60mA

6. Explosion-proof rating: ExdIIBT5

How to wire BMF series 4-20mA flow transmitter

When ordering, users must specify whether DC24V or 12V power supply is required. Wiring should be done according to the diagram provided.

CAUTION: DO NOT CONNECT WIRING WHILE POWERED!

Conclusion

The positive displacement flowmeter itself is synonymous with high precision. Adding 4-20mA output function to it is equivalent to equipping it with "remote eyes and ears", making it not only a precise "measuring scale", but also a real-time and reliable participant in modern automation process control systems, which is an important part of achieving industrial intelligence and refined management.