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SR50AT-Series Sonic Ranging Sensors
13
FIGURE 8-1. SR50AT-CBL
By default, the temperature correction will be on for RS-232 and RS-485
modes. For the SDI-12 output mode, the datalogger must include a
measurement command that has temperature in the output. Otherwise, the
internal temperature correction will not be applied. M2, M3, M4, M7, and M8
commands automatically apply the temperature compensation to the readings.
(p. 14)
, for the complete list of SDI-12
commands.)
Command M9 is used to obtain a temperature measurement without a distance
reading. The M9 command makes it possible for the SR50AT to function as an
SDI-12 temperature sensor.
If the internal SR50AT temperature correction needs to be bypassed, the
temperature output setting will need to be turned off for RS-232 and RS-485
modes. Using measurement commands M, M1, M5, and M6 in SDI-12 mode
will not use the SR50AT probe to compensate for the speed of sound. The
compensation will then need to be done externally as for the SR50A version.
A radiation shield is required for the SR50AT temperature probe. Without a
radiation shield the heating of the sensor from the sun’s radiation can cause
large errors in the temperature reading and this will be reflected in the distance
measurement.
Connect to SR50AT
Temperature Probe
3 m (10 ft) Long
Pigtail End to Datalogger
Length as Required