Invensys Metering Systems (Ludwigshafen, Germany) uses KT 5 contrast sensors from SICK Inc. (Minneapolis) in state-certified automatic testing stations for calibrating water and heater meters.

The sensor detects the rotation of the small star-shaped wheels, called scaling stars, within the meters, as part of the gravimetric testing process.

Up until now, Invensys had been using its own contrast sensor for this task. This was necessary 30 years ago because commercial sensors could not cope with all the possible sensing conditions. For example, the viewing window between the scaling star and the sensor can be made of glass or plastic. In addition, the scaling stars come in many shapes and colors.

Unfortunately, Invensys’ custom sensor had various disadvantages, including high development costs, long delivery periods for purchased parts, high warehousing and commissioning costs and insufficient user-friendliness. The KT 5 has solved these problems. The sensor’s lens was modified for this task. Otherwise, it is a standard device. The sensor is suitable for all meter types and scaling star designs. Therefore, it is no longer necessary to exchange testing station sensors for different meter types.

During the testing process, each sensor impulse must be given out via a signal adapter card in the testing station to the approved testing software. The exact meter value can be determined because the number of impulses is proportional to the particular amount of throughflow.

Since the changeover, the economic efficiency of impulse detection has increased by more than 50 percent.

For more information on sensors, call 800-325-SICK or visit