Senix ultrasonic sensors have a temperature sensor inside the sensor technique to compensate for changes in ambient air temperature. As the ambient air warms or cools, the sensor body temperature follows slowly, and the embedded temperature sensor data is used to adjust the calculation for the speed of sound in a linear relationship.
For even more severe changes in air temperature that require an even faster response, Senix has developed the ToughSonic RTTC system that overcomes the time lag inherent with a built-in sensor and offers customers with an improved compensation option.
ToughSonic Reference Target Temperature Compensation accessory uses an external reference target at the front of the sensor located in the measurement path. Combined with the latest SenixVIEW software, for each measurement the sensor takes two readings; one to locate the reference target, and one to the distant object. Any change in the speed of sound affects both measurements. The reference target location is locked during calibration, and any change in its apparent position is applied proportionally to correct the distant object’s apparent location. The result is a more accurate measurement, unaffected by ambient air temperature, diurnal temperature swings, sensor self-heating, sunshine warming the sensor, cold ambient temperatures or vibration. Field calibrations can be done at any time or temperature.
RTTC equipment includes a reference target which is either added to the front of the sensor or added to the sensor’s mount adapter or riser. Calibration is done in SenixVIEW, Senix’s free configuration and monitor application. It includes steps to locate the reference surface, locate a farther test object, and to determine and enter the actual distance to the test object. Once calibrated, the sensor can be used in tanks, stilling tubes, or over open water channels and flumes. The effects of air temperature swings or sensor warming are nulled. RTTC external targets are available at Senix for ToughSonic 3, 12 and 14 models. SenixVIEW software can be utilized for customers that may want to make their own Reference Target.
The two illustrations below show side by side sensors operating over a canal, one with conventional temperature compensation and one with RTTC compensation. In the conventional, notice the apparent canal depth varies with the extremes of temperature, while in the RTTC plot notice the apparent distance is unaffected by temperature diurnal swings. The temperature effects have been largely eliminated.
Diurnal temperature swings can be ignored, and external heating or cooling of the sensor will not result in incorrect distance or level measurements. The sensor could be exchanged on site and a new calibration could be done on site at any temperature.
The RTTC accessory will improve the sensor’s performance in conditions with significant changes in temperature due to diurnal affects. The intensity of the diurnal changes and how the sensor software is set up will affect the sensor’s ultimate performance.
Part Number Description
UA-RT1-1N Reference Target Adapter, with target for 1 in. NPT THD
UA-RT1-30 Reference Target Adapter, with target for 30mm THD