Campbell Scientific AVW200 AVW200-series Vibrating Wire Interfaces - Page 48
Note that the Signal Strength Amplitude Dest2 returned, If AmpThreshold is
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AVW200-series 2-Channel Vibrating Wire Spectrum Analyzer Modules BeginFreq The BeginFreq parameter is the starting frequency to use for the vibrating wire measurement. The minimum value that can be entered is 100. Refer to the specifications of the vibrating wire sensor for recommended BeginFreq values. EndFreq The EndFreq parameter is the ending frequency to use for the vibrating wire measurement. The maximum value that can be entered is 6500 (typical sweep range is 450 to 6000). Refer to the specifications of the vibrating wire sensor for recommended EndFreq values. ExVolt The ExVolt parameter is the excitation voltage to be used to excite the vibrating wire. Valid options are 1 (5 V peak-topeak) or 2 (12 V peak-to-peak). Therm50_60Hz TheTherm50_60Hz parameter is used to set the integration time for the thermistor in the vibrating wire sensor. Code 0 _60Hz _50Hz Description No thermistor measurement (5 values returned in Dest) Use 60 Hz noise rejection (6 values returned in Dest) Use 50 Hz noise rejection (6 values returned in Dest) Multiplier The Multiplier parameter is the multiplier to be used for the frequency measurements. Offset The Offset parameter is the offset to be used for the frequency measurements. AmpThreshold (for Datalogger OS versions 23 and higher) The AmpThreshold parameter is an optional parameter that is used to define a minimum value, in millivolts, for the amplitude of the signal. If an amplitude less than the threshold is measured, NAN (not-a-number) will be stored for the Frequency measurement. If AmpThreshold is omitted, a default value of 0.01 mV is used. If a value of less than 0.01 mV is entered for this parameter, the precompiler will return an error. Note that the Signal Strength Amplitude ( Dest(2) ) returned by the AVW200 CRBasic instruction is limited in its resolution. See the Note for the "Dest" parameter earlier in this section for more information. To avoid unexpected results, use a value that is an integer multiple of 0.0625 for the AmpThreshold parameter. 40