
Level Switches

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.
Float switches are a type of liquid level sensor that uses a float to operate a switch. They are commonly used to control other devices such as pumps and alarms when a liquid level rises or falls to a specific point. There are two types of float switches: stem-mounted and cable-suspended. Stem-mounted float switches constrain the movement of the float to up and down along a stem. Cable-suspended float switches are as free as the cables they are attached to. A magnet in the float passes over a reed switch with the rising or falling of the liquid, either opening or closing the switch.
Dwyer Float Switches are mechanically actuated floating switches intended to activate electrical components, such as pumps, to start and stop automatically. They are ideal for simple level control of liquids for filling or draining tanks or reservoirs. Counterweights and cable hangers are available to suit a variety of mounting applications.
APG Float Switches have multiple switch points in a single float. They are designed to handle alarm configurations as well as filling or draining tanks. FS Miniature Stainless Steel Float Switches have NSF 169 certification for food-adjacent equipment and can handle temperatures up to 500 degrees F. FL Series stem-mounted float switches have lengths between 6 inches and 12 feet making them a good fit for anything from small totes to process reservoirs and large storage tanks.
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.