Campbell Scientific AVW200-series Vibrating Wire Interfaces - Manual (Page 48)

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-to-
peak) 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 Description
0 No thermistor measurement (5 values returned in
Dest)
_60Hz Use 60 Hz noise rejection (6 values returned in
Dest)
_50Hz 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.
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