Campbell CDM-VW300 Series, User Manual

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Appendix G. CRBasic Program Library
G-16
If TimeIntoInterval (0,1,Sec) Then
CDM_VW300Static (CPI_ADDR,StaticStrain(),Temp(),StrainStdDev()) 'Obtain un-shifted
'static strain.
'Calculate static digits reading (for troubleshooting)
StaticDigits(1) = StaticStrain(1)/GaugeFactor/NomBatchFactor
StaticDigits(2) = StaticStrain(2)/GaugeFactor/NomBatchFactor
'Now shift the given StaticStrain using the Offset/Baseline reading to obtain
'Final/adjusted StaticStrain.
StaticStrain(1) = StaticStrain(1) + StrainBL(1) : StaticStrain(2) = StaticStrain(2) + _
StrainBL(2)
'Calculate static frequency from static digits (for troubleshooting)
StaticFreq(1) = SQR(StaticDigits(1)*1000) : StaticFreq(2) = SQR(StaticDigits(2)*1000)
CallTable static
EndIf
NextScan
EndProg
G.1.11 50 Hz Measurement Example
— One CDM-VW300, Two
Geokon 4000 Sensors with FieldCal()
'===Geokon4000-50Hz2Ch_4-25-13.CR3===
'CR3000 datalogger
'CDM-VW300 vibrating-wire analyzer
'Program to read 50-Hz dynamic data from one CDM-VW300 measuring two Geokon 4000
strain gauges
'IMPORTANT -- Ensure that the CPI address coded on the following line matches the address
'reported for the attached analyzer in the DevConfig or DVWTool software.
Const CPI_ADDR = 1 '<<<<<<<<<<<<<<SET CPI ADDRESS HERE
'Constants specific to the Geokon 4000 strain gauges
Const GaugeFactor = 4.062 'G = 4.062 - Gauge factor taken from sensor manual
Const NomBatchFactor = 0.97 'B=0.97 - Batch Factor taken from sensor calibration sheet
'Output will be in Strain, not Digits nor Frequency
Public Strain(2) : Units Strain() = Microstrain 'Measured strain output in units of Microstrain
Public StrainBL(2) : Units Strain() = Microstrain 'Baseline/offset strain reading in units of
'Microstrain (for calibration)
Public DCode(2) As Long 'Dynamic diagnostic code
Public StaticStrain(2) : Units StaticStrain() = Microstrain 'Static (1Hz) strain reading in 'microstrain
Public StaticDigits(2) 'Calculated Static (1Hz) Digits output (for troubleshooting).
Public StaticFreq(2) : Units StaticFreq) = Hz 'Calculated Frequency (1Hz) from static digits
'(for troubleshooting)
Public Temp(2) : Units Temp() = DegC ' Temperature in DegC
Public TempBL(2) : Units TempBL() = DegC ' Temperature Baseline in DegC
Public StrainStdDev(2) : Units StrainStdDev() = Microstrain 'StdDev of dynamic strain readings
Public ZeroMode 'Mode variable for baseline/offset zeroing calibration
'Configure the CDM-VW300 device
Dim Enable(2) As Long = { 1, 1}
Dim Max_AMP(2) = { 0.002, 0.002}
Dim F_Low(2) = { 300, 300}
Dim F_High(2) = { 6000, 6000}
'Use Hz^2 (1) instead of Hz (0) so we can get to digits
Dim OutForm(2) As Long = { 1, 1}
'Use a multiplier of 0.001 to divide by 1000 and get digits. Then scale further to get to Strain
Dim Mult(2) = { 0.001*GaugeFactor*NomBatchFactor, 0.001*GaugeFactor*NomBatchFactor} 'Digits
(Hz^2/1000) times G times B results in strain
Dim Off(2) = { 0.0, 0.0}
'Use Steinhart-Hart coefficients to get thermistor output in DegC
Dim SteinA(2) = {1.4051E-3, 1.4051E-3}
Dim SteinB(2) = { 2.369E-4, 2.369E-4}
Dim SteinC(2) = { 1.019E-7, 1.019E-7}
Dim RFMB(2) As Long = { 20, 20}
Dim RFAB(2) As Long = { 20, 20}
Dim RFLL(2) = { 400.0, 400.0}
Dim RFHL(2) = {4000.0,4000.0}
Dim RFHY(2) = { 0.005, 0.005}
Dim RFOF(2) As Long = { 100, 100}
CDM_VW300Config (0,CPI_ADDR,0,Enable(),Max_AMP(),F_Low(),F_High(), _
OutForm(),Mult(),Off(), SteinA(),SteinB(),SteinC(), _
RFMB(),RFAB(),RFLL(),RFHL(),RFHY(),RFOF())