
Capacitive Level Transmitters

Level control and measurement in industrial processes is essential to optimize performance and avoid potential problems. Level measurement determines the position of a liquid relative to the top or bottom of a container. Levels that are too high can cause overflow, resulting in safety or environmental problems, while levels that are too low can cause damage to equipment. Fluid level control devices monitor, compare and regulate liquid levels within a process to a set value.
Dwyer Mercoid Series CRF2 is a level transmitter that indicates the level of liquids, powders and bulk materials in a tank. The two-wire 4 to 20 mA output transmitter uses impulse Radio Frequency (RF) admittance measurement to provide reliable accuracy and stability. The transmitter senses the capacitance changes resulting from the height of the material in the tank between the probe and the tank wall. This technology provides immunity to external RF sources as well as minimal interference with radio communication or other electronic systems. The CRF2 comes with either a rigid or flexible probe depending on the application installation need and the probe length required.
Products
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.