LEVEL MEASUREMENT INSTRUMENTS EBOOK DOWNLOAD!
Point level measurement sensors are used to mark a single discrete liquid height–a a level meter, controller on any other level measurement instrument: 1. The WIKA portfolio of level measurement encompasses both continuous measuring instruments and level switches. Depending on the application, different. Our wide range of devices for liquids and solids measurement covers the whole spectrum from basic point level detection to challenging continuous level.
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A simple inspection of the probe will require an ohmmeter connected across the suspect probe and the ground reference. Typically, in most water and wastewater wells, the well itself with its ladders, pumps and other metal installations, provides a ground return.
However, in chemical tanks, and other non-grounded wells, the installer must supply a ground return, typically an earth rod. State dependent frequency monitor[ edit level measurement instruments A microprocessor controlled frequency state change detection method uses a low amplitude signal generated on multiple sensor probes of differing lengths.
Each probe has a frequency separate from all other probes level measurement instruments the array and independently changes state when touched by water. The state change of the frequency on each probe is monitored by a microprocessor which can perform multiple water level control functions.
A strength of state dependent frequency monitoring is long term stability of the sensing probes. The signal strength is not sufficient level measurement instruments cause fouling, degradation, or deterioration of the sensors due to electrolysis in contaminated water.
Sensor cleaning requirements are minimal or eliminated. Use of multiple sensing rods of different length allows the user to intuitively set up control switches at various water heights.
Level Measurement | How do Level Sensors Work? | Omega
Multiple switch controls can be built in to small package while providing complex, application specific functionality using the microprocessor. Low power consumption of the controls is consistent across large and small field applications. This universal technology is used in applications with wide-ranging liquid quality.
Sensors for both point level detection or continuous monitoring[ edit ] Ultrasonic[ edit ] Ultrasonic level sensors are used for non-contact level sensing of highly viscous liquids, as well as bulk solids.
They are also widely used in water treatment applications for pump control and open channel flow measurement. Correction factors can be applied to the level measurement to improve the accuracy of measurement. Turbulence and foam prevent the sound wave from being properly reflected to the sensor; steam and chemical mists and vapors distort level measurement instruments absorb the sound wave; and variations in concentration cause changes in the amount of energy in the sound level measurement instruments that is reflected back to the sensor.
Stilling wells and waveguides are used to prevent errors caused by these factors. Proper mounting of the transducer is required to ensure the best response to reflected sound.
In addition, the hopper, bin, or tank should be relatively free of obstacles such as weldments, brackets, or ladders to minimise false returns and the resulting erroneous response, although most modern systems have sufficiently "intelligent" echo processing to make engineering changes largely unnecessary except where an intrusion blocks the "line of sight" of the transducer to the target.
This vibration must attenuate stop before the echoed signal can level measurement instruments processed. The net result is a distance from the face of the transducer that is blind and cannot detect an object. The requirement for electronic signal processing circuitry can be used to make the ultrasonic sensor an intelligent device.
Ultrasonic sensors can be designed to provide point level control, continuous monitoring or both. Due to the presence of a microprocessor and relatively low power consumption, there is also the capability for serial communication from level measurement instruments other computing devices making this a good technique for adjusting calibration and filtering of the sensor signal, remote wireless monitoring or plant network communications.
The ultrasonic sensor enjoys wide popularity due to the powerful mix of low price and high functionality. Capacitance[ edit ] Capacitance level sensors excel in sensing the presence of a wide variety of solids, aqueous and organic level measurement instruments, and slurries.
The sensors can be designed to sense material with dielectric constants as low as 1. Sludges and slurries such as dehydrated cake and level measurement instruments slurry dielectric constant approx.
Since capacitance level sensors are electronic devices, phase modulation and the use of higher frequencies makes the sensor suitable for applications in which dielectric constants are similar. A danger exists from build-up and discharge of a high-voltage static charge that results from the rubbing and movement of low dielectric materials, but this danger can be eliminated with proper design and grounding.
Appropriate choice of probe materials reduces or eliminates problems caused by abrasion and corrosion. Point level measurement instruments sensing of adhesives and high-viscosity materials such as oil and grease can result in the build-up of material on the probe; however, this can be minimized by using a self-tuning sensor.