Flow Transmitters

More Information about Flow Transmitters

Integrated electronic circuitry in the flow transmitter interprets the signal from the flow meter and can convert it to an electrical voltage proportional to the flow rate. This signal can be further used for process control, monitoring, or custody transfer.

Advanced flow meters, such as Coriolis meters, measure mass flow directly. They function by inducing a vibration in multiple tubes carrying the fluid, while sensors monitor changes in the vibration caused by the moving fluid. A Coriolis meter is capable of providing measures of mass flow, volumetric flow rate, and fluid density all in one unit.

Other types of flow meters use ultrasonic or magnetic field technologies to measure flow velocity, which can then be related to flow rate. These meters have no moving parts, leading to less maintenance and longer device life.

In all cases, the choice of flow transmitter and meter should be based on the fluid or gas to be measured, its temperature, pressure, and density, as well as the required accuracy, flow ranges, and the suitability of the device for the installation environment.

Transmitters vs Transducers

Some of the most common types of transmitters and transducers can be found on pressure instruments. Examples of these include: drop-in well pressure devices and devices that measure the pressure in a pipe or gas chamber. Transmitters and transducers can also be found on flow and speed measurement devices. 

What is the difference between transmitters and transducers? 

The main difference is the way they send data to the monitoring device, like a PLC. In terms of measurement, the transmitter will reference a measuring unit by sending a milliamp signal (such as 4-20 mA). A transducer will reference a measuring unit by sending a voltage signal, typically in volts or millivolts.  

Why have the two different types of transmission methods? 

The method will depend on the application. If the electrical connection in the application travels a short distance, a pressure transducer is the better choice. Pressure transducers are smaller with fewer active electronic components that can be upset by electromagnetic interference. Also, the voltage signals transmitted over longer distances are subject to voltage drop and signal corruption. A transmitter is better for transmitting signals over a long distance.