Level

Level Transmitters

Level transmitters are sensors which produce an electronic output, normally 4-20mA, which represents a continuous level measurement in a tank or vessel as the level changes. The level output can be displayed locally at the tank or vessel with an LCD display and remotely in a control room.

The level can be displayed in engineering units, for example, feet, gallons, inches, percent full, and many other units. Some displacer type level devises can provide a pneumatic output, usually 3-15psig or 6-30psig. These are often mounted on or close to a pneumatic control valve. The output is used to move the valve so that a level setpoint for a tank or vessel is maintained.

There are many level sensor options which include acoustic, caged displacers, capacitive, float, guided wave radar, hydrostatic pressure, Laser, magnetorestrictive, non contact radar and ultrasonic.
There are many special level measurement applications. For one example, facilities measure the oil-water interface in sump pits or vessels which collect oily water. The oil and water separates, forming an oil level on the top with water on the bottom. Knowing oil/water the interface point can help prevent the unplanned removal of oil as the sump or vessel is drained, and to prevent oil overflow as the sump or vessel is filled.

Level Alarms Annunciators

Alarms are used to monitor flow, level, and pressure in processes. When the process conditions exceed limits set in the alarm unit, a signal is sent to activate horns, lights, and control room alarms so that corrective action can be taken.

Level Controllers

Universal electric controllers are used to control process variables such as flow, level, pressure, and temperature in single or dual-loop operations. The controllers can take in 4-20mA analog input signals and RTDs, or thermocouples directly. The controller compares the input to a setpoint. As the input deviates from the setpoint, the controller sends an analog or digital signal to a device such as a control valve that operates to bring the measured unit back to the setpoint. Many controllers have RS-485 interface so they can be used with personal computers or larger systems.

Oil Water Interface Level Measurement

Level transmitters are sensors which produce an electronic output, normally 4-20mA, which represents a continuous level measurement in a tank or vessel as the level changes. The level output can be displayed locally at the tank or vessel with an LCD display and remotely in a control room.

The level can be displayed in engineering units, for example, feet, gallons, inches, percent full, and many other units. Some displacer type level devises can provide a pneumatic output, usually 3-15psig or 6-30psig. These are often mounted on or close to a pneumatic control valve. The output is used to move the valve so that a level setpoint for a tank or vessel is maintained.

There are many level sensor options which include acoustic, caged displacers, capacitive, float, guided wave radar, hydrostatic pressure, Laser, magnetorestrictive, non contact radar and ultrasonic.
There are many special level measurement applications. For one example, facilities measure the oil-water interface in sump pits or vessels which collect oily water. The oil and water separates, forming an oil level on the top with water on the bottom. Knowing oil/water the interface point can help prevent the unplanned removal of oil as the sump or vessel is drained, and to prevent oil overflow as the sump or vessel is filled.

Level Panel Meters Indicators

Panel meters and indicators are used to receive and display process measurements from Flow, Level, Pressure, Temperature Transmitters and other devices. In addition to displaying the measured process variable in engineering units, the panel meters are often used to display flow totals, level in multiple units like gallons and inches, and alarms when a process exceeds limits set by the user.

In addition to displaying process and alarm information, a retransmission of the process variable, usually a 4-20mA signal, and/or digital relay outputs can be used to send information to control rooms, distributed control systems, or to other devices like pump controls which provide single on/off or multi-pump alternation.

As their description indicates, panel meters and indicators are usually mounted in panels or enclosures where operating personnel can monitor them.

Level Switches

Level switches are sensors which produce an electric or electronic output when the level of liquid or solid in a vessel reaches a specific point.

There are many sensor options including capacitive, conductivity, displacer, float, fork, optical, paddle and vibrating rod.

Normally level switches send an electronic or electric contact output to a valve or other device to begin or end the filling or draining operation for a tank or vessel