Campbell CDM-VW300 Series, Руководство пользователя

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User Manual
3
measurement of sensor signals too weak to be measured with other
instrumentation. See Appendix A,
Measurement Theory , for more information.
Dynamic vibrating-wire measurements require a complete system of
instrumentation. This manual focuses on the use of CDM-VW300 series
analyzers, but it also gives basic guidance on system configuration.
4.1 Channel Allocations
As illustrated in Figure 4-1, the CDM-VW300 simultaneously measures two
vibrating-wire sensors. Figure 4-2 shows that the CDM-VW305 has the capacity
to measure eight sensors. When more than eight channels are needed, multiple
devices are attached to the same datalogger through the CPI bus. See Section
7.7.7,
Maximum Number of Analyzers on a Datalogger , and Appendix C, CDM
Devices and CPI Bus , for details on connecting multiple analyzers to a CPI bus.
Figure 4-1. Two-channel CDM-VW300 wiring panel
Figure 4-2. Eight-channel CDM-VW305 wiring panel
4.2 Measurement Rates
CDM-VW300 analyzers use patented techniques to measure sensors at rates from
1 to 333.3 Hz. Systems that exclusively require rates slower than 1 Hz should use
a Campbell Scientific AVW200-Series Vibrating-Wire Spectrum Analyzer.