Campbell Scientific CSAT3 3-D Sonic Anemometer - Manual (Page 33)

CSAT3 Three Dimensional Sonic Anemometer
data condition also occurs when the datalogger’s execution frequency (inverse
of the execution interval) is much greater than the execution parameter the
anemometer was told to use.
61441, SDM Communications Error. The datalogger and CSAT3 are unable
to communicate correctly. Extending the SDM cable beyond the standard 7.62
m (25 ft.) and not slowing down the SDM clock with the SDMSpeed ()
instruction (CRBasic), or Instruction 115 (CR23X or CR10(X)) or 108 (21X) is
the most common cause of this error. See Appendix D for details on
identifying the appropriate SDM clock rate for a given cable length.
61442, Wrong CSAT3 embedded code. The CSAT3 is running a version of
embedded code prior to version 3. Starting with embedded code version 3 and
the CR5000, the configuration of the CSAT3 is done within the instruction,
rather than in separate datalogger code. CSAT3s running a version of
embedded code prior to 3 and deployed in systems using a CR3000, CR1000,
CR5000, CR800/850, or CR9000X datalogger must upgrade to a version of
CSAT3 embedded code that is 3 or greater.
TABLE 10-6. CSAT3 Diagnostic Flags
Bit Set
High Description Comment
b15 Difference in the speed of
sound between the three
non-orthogonal axes is
greater than 2.360 m s –1
(~ 4 °C @ 25 °C)
The anemometer path length may
have been altered or the
anemometer head is broken.
b14 Poor signal lock There may be an obstruction in the
anemometer path or on the
transducer face.
b13 Sonic signal amplitude too
high
An obstruction, in the anemometer
path or on the transducer face, was
removed.
b12 Sonic signal amplitude too
low
There may be an obstruction in the
anemometer path or on the
transducer face.
10.5 SDMTrigger ()/SDM-Group Trigger (P110)
A SDM Input/Output instruction that controls SDM devices that support the
group trigger protocol, including the CSAT3. Up to 15 group trigger devices
can be connected to the SDM bus. All group trigger devices are triggered to
make simultaneous measurements with the SDMTrigger/SDM Group Trigger
(P110). The data from each device is then retrieved with the appropriate
device specific instruction. For the CSAT3, the CSAT3 ()/SDM-CSAT3
(P107) Instruction with the “Get data after Group Trigger” Command/Option
(97, 98, or 99) is used to retrieve the data.
10.6 Example CRBasic Datalogger Program
In the following example, a CR3000 is used to collect data from the CSAT3
using SDM communications. The CR3000 will trigger each wind
measurement over the SDM bus and retrieve the data.
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