Accubar SDI-12 Barometric Pressure Sensor Operations & Maintenance Manual Rev-B 30 Nov 2017
pg. 17
Other Measurements
The SDI-12 standard allows for other measurement commands such as M1, M2 etc., other current
measurement commands such as C1, C2, etc., other non-concurrent measurements with CRC-16 such as
MC1, MC2, etc, and other concurrent measurement with CRC-16 such as CC1, CC2, etc. This unit
maintains symmetry across all four classes of commands, that is, it returns the same information to a C1
as it does to a M1 or a MC1 or a CC1. The ACCUBAR
®
supports the following optional measurement
commands:
aM1!
aC1!
aMC1!
aCC1!
measure mB (hPa) using factory calibration. Do not
apply any user scaling, station elevation or offsets. This
returns 1 value and the units are fixed to mB (hPa).
aM2!
aC2!
aMC2!
aCC2!
measure temperature (Celsius or Fahrenheit). This
returns two values: the temperature and the units. The
units will be 0 for Celsius and 1 for Fahrenheit.
aM3!
aC3!
aMC3!
aCC3!
measure user scale, user offset, elevation offset. Use
this if you want to view the user-entered values that
can affect the value returned by the M command.
aM4!
aC4!
aMC4!
aCC4!
measure calibration lab scale and offset. Use this if you
want to view the calibration lab values that can affect
the value returned by the M, C, MC, and CC commands.
aM6!
aC6!
aMC6!
aCC6!
Measure temperature and pressure. The output is the
concatenation of the M2 and M commands.
Temperature, temperature units, Pressure, Pressure
units.
aM7!
aC7!
aMC7!
aCC7!
Measure mB and degrees C using factory calibration.
Do not apply any user scaling, field calibration or
offsets. This returns two values and the units are fixed
to mB and degrees C.
Remember to issue the aD0! command after the measurement is complete in order to retrieve the data.
Changing the Units
As noted above, the aM! command can return the pressure in several different units. The selection of
the units is made using the XUP command:
