Campbell Scientific CSAT3 CSAT3 3-D Sonic Anemometer - Page 31
SDMTrigger /SDM-Group Trigger P110, 6 Example CRBasic Datalogger Program
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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 b15 b14 b13 b12 Description Difference in the speed of sound between the three non-orthogonal axes is greater than 2.360 m s-1 (~ 4°C @ 25°C) Poor signal lock Sonic signal amplitude too high Sonic signal amplitude too low Comment The anemometer path length may have been altered or the anemometer head is broken. There may be an obstruction in the anemometer path or on the transducer face. An obstruction, in the anemometer path or on the transducer face, was removed. 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. 23