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Electronic Flow Meters: Advanced Digital Microprocessor Flow Telemetry Stations

Quick Answer: Electronic flow meters with digital microprocessor flow telemetry stations combine a primary flow sensor, a digital signal processor, and a remote data transmission unit. They measure flow rate, total flow, temperature, and pressure. Silver Automation Instruments supplies these systems for oil and gas, water and wastewater, chemical, food and beverage, and marine projects from DN15 to DN300.

What a Digital Microprocessor Flow Telemetry Station Does

In practice, a digital microprocessor flow telemetry station is not one single device. It is a flow meter plus a compact telemetry unit. The flow meter outputs a raw signal. The microprocessor filters the signal, calculates mass flow or volume flow, and stores totalizer data. After that, the telemetry module sends data to a SCADA system, a PLC, or a cloud dashboard.

We see two common architectures on customer sites. In one setup, a Coriolis mass flow meter measures kg/h and density directly. The transmitter sends 4-20 mA HART and RS485 Modbus data to a local RTU. In another setup, an electromagnetic flow meter measures volumetric flow in m3/h. A separate data logger uploads values over 4G to a server in Singapore or Perth.

Flow Meter Types That Work with Digital Telemetry Stations

Electromagnetic flow meters are a good fit for conductive liquids. Minimum conductivity is typically 5 µS/cm. These meters work well for raw water, wastewater, brine, and chemical dosing. Common sizes are DN15 to DN600. Accuracy is ±0.5 percent of reading. Pressure ratings go up to PN40. For desalination plant seawater intake, a DN400 electromagnetic flow meter with rubber liner and titanium electrodes is a standard choice.

Coriolis mass flow meters handle liquids and gases. They measure mass flow, density, and temperature in one device. Typical accuracy is ±0.2 percent. That accuracy level is useful for custody transfer, fuel oil blending, and LPG measurement. A customer in the Middle East uses a DN50 Coriolis meter for diesel fuel transfer. The meter sends kg/h and density data to a telemetry station. The station alerts operators when density falls outside the target range.

Ultrasonic flow meters do not contact the fluid. Clamp-on models are used for temporary flow surveys on large pipes. Inline models are used for custody transfer of demineralized water or chemicals. Vortex flow meters are common for steam, compressed air, and natural gas. They output volumetric flow or mass flow when paired with pressure and temperature compensation. An example is a vortex flow meter on a steam header in a food processing plant. The pipeline is DN80. Steam pressure is 8 bar. Steam temperature is 175 °C. Temperature compensation uses a PT100 sensor. The telemetry unit calculates kg/h and total steam consumption per shift.

Oval gear flow meters work for clean, viscous liquids. They are used for diesel, fuel oil, solvents, resins, and food oils. Viscosity can range from 1 cP to 1000 cP. A paint manufacturer in Southeast Asia uses a DN25 oval gear flow meter for solvent batching. A marine fuel supplier in Singapore uses a DN40 oval gear flow meter for diesel transfer to service vessels. The meter outputs a pulse signal. The digital station converts pulses to liters and sends batch totals to a PLC.

Thermal mass flow meters are used for low flow gas measurement. Typical applications include biogas, natural gas, and compressed air. They measure flow in Nm3/h or standard cubic meters per hour. A wastewater plant in Latin America uses a thermal mass flow meter to monitor biogas flow from an anaerobic digester. The telemetry station records flow rate and total gas volume every minute.

Key Output Signals and Communication Protocols

The most common output from these flow meters is 4-20 mA with HART. Man