Data Sheet

Page 10

Web: www.maxbotix.com

PD11500t

MaxBotix

Inc.

Patent 7,679,996

HRXL-MaxSonar

WR/WRC

™

Series

MaxBotix Inc., products are engineered and assembled in the USA.

Temperature Compensation

On Board – Internal Temperature Compensation

The speed of sound in air increases by about 0.6 meters per second, per degree centigrade. Because of this, each

HRXL-MaxSonar-WR is equipped with an internal temperature sensor which allows the sensor to apply compensation for

speed of sound changes.

The actual air temperature of the path between the sensor and the target may not match the temperature measured at the

sensor itself. Sensors can be mounted in vertical applications, or applications where the environment temperature gradient

is severe. These users may experience a temperature measurement error which will affect the sensor accuracy. For

example, buildings with a height of 3-meters can have floor to ceiling temperature variations of 5°C or more.

Because of these temperature effects, users desiring the highest accuracy output are encouraged to use a properly mounted

external temperature sensor or to manually account for this measurement error.

HR-MaxTemp, an External Temperature Sensor

Although the HRXL-MaxSonar-WR has an internal temperature sensor; for best accuracy, users are encouraged to use the

optional external temperature sensor. On power-up, the HRXL-MaxSonar-WR will automatically detect an attached

HR-MaxTemp temperature sensor and begin to apply temperature compensation using the external temperature sensor.

The external temperature sensor allows for the most accurate temperature compensation, by allowing temperature

readings to be taken that better reflect the composite temperature of the acoustic ranging path. For best results, users are

encouraged to connect the temperature sensor midway between the HRXL-MaxSonar-WR and the expected target.

_______________________________________________________________________________________________________________________________________

Voltage vs Temperature

The graphs below show minimum operating voltage of the sensor verses temperature.

The graph pictured below is applicable to the following sensors:

MB7360,MB7369,MB7380 & MB7389