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Here's how they work...
LEVELMARK™ Ultrasonic Gap Switches use proven, reliable ultrasonic technology. The Levelmark control unit transmits an inaudible
acoustic signal across the gap in the sensing element. When the gap is not filled with a liquid the signal strength decreases.
When liquid fills the gap the across-gap signal increases. The signal crosses the gap which causes the state of the output device
to be changed.
LEVELMARK™ Ultrasonic Gap Switches are specially suited for your difficult applications. The effect of ambient noise is eliminated
by the use of frequency selective circuits. This rules out a major cause of false alarms. These circuits also allow a higher
in-band signal to be generated with less power than is normally required. You get highly effective sensitivity without
using expensive very high signal-to-noise (S/N) ratio sensing elements.
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Output Flexibility
LEVELMARK™ Ultrasonic Gap Switches are available with a variety of output options to meet your process control needs. For optimum
safety, and peace of mind, a 4-20 mA loop output, divided into current windows, allows for intrinsically safe connections. A
second option is the optoisolated, open collector transistor, output. This option provides a "bounceless" solid state switch
closure. These switches can be used with Distributed Control Systems (DCS) or Programmable Logic Controllers (PLC) without
costly "de-bouncers" or signal conditioners. A relay contact closure option is also available.
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