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Echotel® 940/941 compact economical ultrasonic level switches

Echotel® Model 940 and 941 Ultrasonic Level Switches are compact integral units that utilize pulsed signal technology to perform high or low level measurement in a wide variety of liquid applications. These switches feature a 316 stainless steel tip-sensitive transducer that is offered in a variety of NPT, flanged, and sanitary process connections. The compact electronics are completely encapsulated just above the process fitting.

The Model 940 offers a 1-amp SPDT relay output. The Model 941 has a mA current shift output.

Echotel 941
Technology

Ultrasonic contact

Ultrasonic contact switches use a pair of piezoelectric crystals that are encapsulated in epoxy at the tip of the transducer for level measurement. The crystals are made of a ceramic material that vibrates at a given frequency when subjected to an applied voltage. The transmit crystal converts the applied voltage from the electronics into an ultrasonic signal. When liquid is present in the gap, the receive crystal senses the ultrasonic signal from the transmit crystal and converts it back to an electrical signal.

Ultrasonic contact

Features

  • Pulsed electronics for excellent performance in difficult process conditions and superior immunity from sources of electromagnetic noise
  • Advanced transducer design provides reliable operation by draining viscous liquids and ignoring foam in turbulent applications
  • Suitable for SIL (Safety Integrity Level) 2 loops (FMEDA analysis data available)
  • Extremely compact unit is easily installed in areas where access space is limited
  • No calibration or configuration necessary
  • 1 amp SPDT relay output (940), 8/16 mA current shift output (941)

Options

  • NPT, ASME flanges and Tri-Clamp sanitary fittings available
  • Available in lengths from 1 to 100 inches (3 to 250 centimeters)

Applications

Operating principle

Ultrasonic energy detects the presence or absence of liquid in a tip sensitive transducer gap. The principle behind contact ultrasonic technology is that high frequency sound waves are easily transmitted across a transducer gap in the presence of liquid, but are attenuated when the gap is dry.

The transducer uses a pair of piezoelectric crystals that are encapsulated in epoxy at the tip of the transducer. The crystals are made of a ceramic material that vibrates at a given frequency when subjected to an applied voltage. The transmit crystal converts the applied voltage from the electronics into an ultrasonic signal. When liquid is present in the gap, the receive crystal is able to sense the ultrasonic signal from the transmit crystal and convert it back to an electrical signal. This signal is sent to the electronics to indicate the presence of liquid in the transducer gap. When there is no liquid present, the ultrasonic signal is attenuated and is not detected by the receive crystal.

接触式超声波操作原理
接触式超声波操作原理

Approvals

CSA IS, NI
FM IS, NI

Other approvals are available. Consult factory for more details.

Downloads

Approvals & certificates

Canadian certificate Echotel® 94X 96X - IS
FM certificate Echotel® 94X & 96X - XP, IS, DIP, NI
FMEDA Report Echotel 940
FMEDA Report Echotel 941

Instruction manuals

Echotel® 940/941 I&O Manual
Echotel® Model 940 and 941 Ultrasonic Level Switches are compact integral units that utilize pulsed signal technology to...

Product catalogs

Echotel® 940/941
Echotel® Model 940 and 941 Ultrasonic Level Switches are compact integral units that utilize pulsed signal technology to...

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