News for Process Automation 1/2016

A Vibrating Fork

Sets the Tone

In Brief:

Vibration Measuring Principle

Imagine a fork that is caused to vibrate by a piezoelectric drive –

i.e. due to changes in electric polarization. These changes create

what is known as a resonance frequency. Immersing the vibrating

fork in a liquid causes the fork’s natural resonance to decrease

due to the change in the density of the surrounding medium. The

electronics in the limit switch monitor the resonance frequency

and indicate whether the vibrating fork is oscillating in air or

covered with liquid. A signal is then emitted via the DC-PNP or

AC/DC electrical connection.

Level Measurement

Whether you want to determine

your storage capacity or obtain accurate information

about tank contents in real time, the Vibracon LVL-A7

reliably takes care of measurement tasks.

Thanks to the solid overflow and dry run protection offered by the new

Vibracon LVL-A7 vibration limit switch, reliable monitoring of your

liquid measurement process is guaranteed – even for applications in

the food industry where hygiene is critical (Vibracon LVL-A7H). Level

measurement technology has a broad range of applications, since

storage tanks can contain such a wide variety of materials. While other

measuring principles commonly fail as a result of the particular filling

substances or tough environments in question, the Vibracon LVL-A7

offers a high level of resistance, taking factors such as conductivity,

deposits, currents, or air bubbles in its stride. This is partly due to the

robust stainless steel housing (316L), which ensures a high level of

durability as no maintenance is required. This particular vibration limit

switch also features no mechanically moving parts that can wear out

or break. The plug-and-play functionality offered by the device ensures

the Vibracon is easy to handle as well as install, and what’s more,

the device can offer all of these benefits within a temperature range of

–40 °C to +150 °C.