logger retrieves the data with the
D!
command on the next scan. Another measurement request
is then sent so that data are ready on the next scan.
Wintersense SDI-12 supports cyclic redundancy checks (CRC) to enhance error detection. See
Start measurement commands with cyclic redundancy check (aMC! and aCC!)
(p. 33) for more
information.
NOTE:
The Wintersense SDI-12 needs to be turned on for 3 seconds before it can receive an SDI-12
command.
Table 7-2: SDI-12 commands
SDI-12
1
command
Values returned or
function
Units
Max. sensor
response time
(sec)
aM!
,
aC!
1. Surface temperature
2. Air temperature
3. Air relative humidity
4. Dew point temperature
5. Angle
6. Supply voltage
7. Sensor body temperature
1. °C
2. °C
3. %
4. °C
5. deg
6. V
7. °C
8
aM1!
,
aC1!
1. Surface temperature
2. Sensor body temperature
1. °C
2. °C
8
aM2!
,
aC2!
1. Air temperature
2. Air relative humidity
1. °C
2. %
0
aM3!
,
aC3!
Angle
deg
0
aM4!
,
aC4!
Supply voltage
V
0
aM5!
,
aC5!
Dew point temperature
°C
0
Wintersense SDI-12
10
