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Gilson Engineering Sales, Inc. 

October, 2014 

Open Channel Flow meter and Level Controller
Ringback in Ultrasonic Transducers
Radar Level Transmitter for Solids
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Want to simplify configuring your Siemens ultrasonic or radar level control for open channel flow or well pump control?  Download the configuration utility from the Gilson website as follows:

Open Channel Flow Meter and Level Controller 

The Siemens SITRANS LUT400 series controllers are compact, single point, long-  range ultrasonic controllers for continuous level, or volume measurement of liquids, slurries, and solids, and high accuracy monitoring of open channel flow.


The SITRANS LUT400 comes in three different models, depending on the application, level of performance and functionality required: LUT400-2


  • SITRANS LUT420 Level Controller: Level or volume measurement of liquids, slurries, and solids, as well as basic pump control functions, and basic data logging capability
  • SITRANS LUT430 Level, volume, Pump and Flow Controller: Includes all features of the LUT420 plus a full suite of advanced pump control and alarm functionality, open channel flow monitoring, and basic flow data logging capability
  •  SITRANS LUT440 High Accuracy OCM: Our most featured, highest accuracy model. Includes all features of the LUT430, plus the industry's best accuracy ( 1 mm within 3 m), full suite of advanced control functionality, and enhanced flow logging capability

Key applications: wet wells, reservoirs, flumes/weirs, chemical storage, liquid storage, hoppers, crusher bins, dry solids storage.  

View video presentation of LUt400
Click to view video presentation of LUT400


Ringback in Ultrasonic Transducers 

One of the more common causes of ultrasonic level sensor errors is a phenomenon known as ringback. Ringback is an installation problem that gives the customer a false high reading or alarm.


Since the ultrasonic transducers use a sound wave to calculate the distance to the level, they need to vibrate internally to create that sound. The transducer receives an electrical pulse from the transmitter causing the transducer to vibrate. When the electrical pulse has ceased, the transducer continues to vibrate. This continued vibration is ring down. During this period of time known as ring down, the ultrasonic system is unable to measure. Basically, the sensor is still ringing when it is trying to listen for a return echo.


Ringing can be prevented by following a few installation guidelines:

  1. Do not over-tighten the transducer. By over-tightening, we cause the transducer, coupling, and mounting device to vibrate, causing extended ringing. This rule applies to both thread and flange mount transducers. You should tighten a transducer only finger snug where possible according to the area codes.
  2. Use a non-metal mounting material. Plastic or rubber does not ring as well as metal. By placing a non-metallic coupling on a thread mounted transducer or inserting a non-metal gasket on a flange mounted transducer, we can reduce the ringing.

Temperature can add to this problem. When installing a transducer in an area where there will be temperature swings, it is even more important to follow the mounting guidelines. As temperature decreases, the mounting becomes tighter as the material shrinks. This also can increase ringing.


For more troubleshooting tips with ultrasonic level sensor, take a look at the following video.


Siemens Hydroranger Troubleshooting video
Siemens Hydroranger Troubleshooting video


Radar Level Transmitter for Solids

The LR560 is the first level transmitter in the world to operate at 78GHz frequency.  The high frequency gives the unit a narrow 4 beam angle and allows us to eliminate the need for a horn.  We no longer have to worry about obstructions in the tank or tall mounting nozzles.  The LR560 is a 2-wire unit that can measure out to 300 feet.  The Quick Start Wizard helps you set up the unit in a few minutes and includes graphics and a backlight.  The unit is resistant to dust build up, so this is ideal for your bulk solids measuring.  This unit has been tested in applications across the country including cement, plastic pellets,   coal, sand, lime, and hot mix asphalt.  The LR560 may be configured via the integral display interface, remote hand programmer, or via HART.



- Advanced Algorithmic Signal Processing.

- Auto False-Echo Suppression.

- High resolution graphical user interface.

- Built-in Vortex purging system guarantees no build-up on lens antenna face.

- Optional Local Display Interface.

- HART, Profibus PA and Foundation Fieldbus protocols.

- General Purpose, or FM Cl I, Div. 2, Gr. A,B,C,D, Cl II, Div.1, Gr. E,F,G, Cl III.


The following video shows how easy it is to install and configure the LR560 transmitter.

SITRANS LR560 Installation
SITRANS LR560 Installation

Download LR560 datasheet