To compensate for changes in ambient air temperature, Senix ultrasonic sensors have a temperature sensor inside the sensor. The sensor body temperature slowly follows as the ambient air warms or cools and the embedded temperature sensor data is utilized to modify the calculation for the speed of sound in a linear relationship.
Senix has developed the ToughSonic RTTC system for more severe alterations in air temperature that need an even quicker response. It overcomes the time lag inherent with a built-in sensor and provides customers with an enhanced compensation option.
The ToughSonic Reference Target Temperature Compensation accessory utilizes an external reference target at the front of the sensor which is in the measurement path. The sensor takes two readings for each measurement when combined with the latest SenixVIEW software; one to the distant object and one to locate the reference target.
Any alteration to the speed of sound influences both measurements. During calibration, the reference target location is locked and any change in its apparent position is applied proportionally to correct the distant object’s apparent location.
The result of this is a more accurate measurement that is unaffected by diurnal temperature swings, sunshine warming the sensor, ambient air temperature, cold ambient temperatures, sensor self-heating, or vibration. Field calibrations can be performed at any time or temperature.
Easy Setup and Use
RTTC equipment includes a reference target that is either added to the sensor’s mount adapter or riser or added to the front of the sensor. Calibration is performed in Senix’s free configuration and monitor application, SenixVIEW.
It includes steps to locate a further test object, locate the reference surface, and to establish and enter the actual distance to the test object. The sensor can be employed in stilling tubes, tanks, or over open water channels and flumes once it is calibrated. The influences of air temperature swings or sensor warming are nulled.
RTTC external targets are available at Senix for ToughSonic 14 models, but for customers that may want to make their own reference target, SenixVIEW software can be used.
Example of RTTC Compensation
The RTTC accessory is mounted to the front of the sensor to create a small target. During calibration, the reference target location is locked and to correct the distant object’s apparent location, any change in its apparent position is applied proportionally.
The RTTC accessory mounts to the front of the sensor and creates a small target. 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.
External heating or cooling of the sensor will not result in incorrect distance or level measurements and diurnal temperature swings can be ignored. The sensor could be exchanged on site and a new calibration could be performed on site at any temperature.
This illustration above shows a canal level that appears to vary as the air temperature fluctuates over several days. The ultrasonic sensor uses a conventional method of temperature compensation. At higher temperatures, the canal surface reads closer and plots as deeper water. The dip seen is from a control gate opening.
Sensor with Reference Target Temperature Compensation (RTTC).
The RTTC accessory will only enhance the sensor’s performance in conditions with significant alterations in temperature due to diurnal effects. The intensity of the diurnal alterations and how the sensor software is set up will affect the sensor’s ultimate performance.
||Reference Target Adapter, for 1 in. NPT THD
||Reference Target Adapter, for 30 mm THD
This information has been sourced, reviewed and adapted from materials provided by Senix Corporation.
For more information on this source, please visit Senix Corporation.