Level Measurement

What are the types of vibration switches that are used for level measurement

What is a vibration level switch and what are its types

Vibrating level switches are used to do the level measurement, the operating is based on detecting the damping in a submerged probe when it is submerged in a process medium. There are three types of vibration switches and they are reed, probe, and tuning fork. Mostly all of them have a similar operating method and they also have similar applications, they can be distinguished by their configurations and operating frequencies.

What are the types of vibration level switches and how do they work?

Vibrating tuning fork

The vibrating level measuring device which has a tuning fork would vibrate at its natural resonance frequency with the help of a piezoelectric crystal, and it will be located at the base of the probe. When the fork comes in contact with the material then the frequency will vary and it would switch a relay. So when the switch is immersed in a process solution, a frequency shift would happen. So if the level decreases below the fork the relay will be reversed.

What are the advantages of vibrating tuning fork?

  • There are no moving parts so no maintenance is needed
  • It can be mounted according to our required position
  • Its size is small so we can mount it easily in any location
  • High accuracy
  • They are independent of medium characteristics
  • Reliable point level switching
  • It can be set up without adjustment to medium
  • Rugged and reliable

What are the disadvantages of vibrating tuning fork?

  • Material build-up can happen in between the tines
  • These build up material would affect the measuring accuracy
  • It can’t be used in vibration bins
  • We cannot easily change the switch setting
  • They need protection from the materials that are charged from the top

What are applications of vibrating tuning fork?

  • It can be used for the level control of the liquid
  • It is used in chemical processing
  • Food and beverage industries


The reed switch consists of a paddle, receiver, and a driver, vibrations will be created by the driver coil in the paddle and this vibration will be damped out if the process material comes in contact with it. This switch can detect both rising and falling levels, and the material depth over the paddle increases as the process fluid density drops. We can use reed switch in non-contact type applications, it will perform better in this type of applications

Vibrating probe

The vibrating probe is a round stainless steel material that will extend to a material. It has a drive and a sensor and both of them are piezoelectric elements. One would create the vibration and the other will measure it. So the probe will be buried under the process material and its vibration is damped and this would trigger the switch. Vibrating probe sensors are used to monitor powders, bulk solids, and granular materials such as cement, plastic pellets, grain flour, etc.


post-graduate in Electronics & communication.

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