Gilson Engineering Sales, Inc. 

October, 2014 

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 has introduced the Sitrans FM MAG 8000 for bulk water metering applications. It is a battery-operated electromagnetic flow meter designed as a cost-efficient water metering solution to manage water consumption for applications such as water distribution, revenue metering and crop irrigation.

The Sitrans FM MAG 8000 for Irrigation features battery power for installation where power availability is a concern. The unit maintains a measurement accuracy rate of 0.8%, and as there are no moving parts, the meter is not prone to typical wear and tear, thus reducing maintenance and operational costs. The meter's IP68 enclosure offers security and durability in flood-prone areas, or even underground. Features include: 

• Compatible with AMI and AMR systems.
• Available in sizes 2"-48".
• Direct burial sensor, IP-68
• NSF compliant. No lead
• 6 - 10 year battery
• Fire Mashall Approval for 2"-12" meters 

View video presentation of Mag8000 flowmeter                  

SITRANS F M MAG 8000 flowmeter

  Download Mag8000 Datasheet