Campbell CDM-VW300 Series User Manual Download Page 85

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Appendix E. Calculating Measurement Error

E-3

E.5 Example Error Calculation: DGSI Piezometer

52611099

For Durham Geo Slope Indicator piezometer 52611099, when using gauge factors

, and

, the formula for pressure,

, derived from frequency is given as:

P = Af

+ Bf + C

The resulting noise (effective resolution) formula is then:

∆P = (2Af + B)N

∆P = 2AfN + BN

Summary of Contents for CDM-VW300 Series

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Page 3: ...he repair is under guarantee or not Please state the faults as clearly as possible and if the product is out of the guarantee period it should be accompanied by a purchase order Quotations for repairs can be given on request It is the policy of Campbell Scientific to protect the health of its employees and provide a safe working environment in support of this policy a Declaration of Hazardous Mate...

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Page 5: ...al cell phones and aerials may also not be applicable according to your locality Some brackets shields and enclosure options including wiring are not sold as standard items in the European market in some cases alternatives are offered Details of the alternatives will be covered in separate manuals Part numbers prefixed with a symbol are special order parts for use with non EU variants or for speci...

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Page 7: ...tions 7 6 Installation 9 6 1 Laboratory Mode Installation 10 6 1 1 Laboratory Mode Installation Equipment 10 6 1 2 Laboratory Mode Installation Procedure 10 6 2 Field Mode Installation 16 6 2 1 Field Mode Installation Equipment 16 6 2 2 Field Mode Installation Procedure 16 7 System Operation 23 7 1 PC Based Tools 23 7 1 1 Software and Driver Installation 23 7 1 2 Using DVWTool 24 7 1 2 1 Ensure Co...

Page 8: ...d Connections 41 7 7 6 Communication Connections 41 7 7 6 1 SC CPI to CPI Bus Connection 41 7 7 6 2 Datalogger to SC CPI Connection 41 7 7 7 Maximum Number of Analyzers on a Datalogger 42 7 8 Operating System 43 7 9 Power Up Sequence 43 7 10 CRBasic Programming 43 7 10 1 Writing Programs 43 7 10 2 Sending Programs to the Datalogger 45 7 11 System Adjustments 45 7 11 1 Frequency Range 45 7 12 Syste...

Page 9: ...1 4 CPI Grounding C 3 C 1 6 Addressing C 3 C 2 Distributed Architecture C 3 D Digits Conversion D 1 D 1 Example Frequency to Digits to Displacement D 1 E Calculating Measurement Error E 1 E 1 Example Error Calculation Geokon Strain Gauge E 1 E 2 Example Error Calculation DGSI Embedment Strain Gauge E 2 E 3 Example Error Calculation DGSI Spot Welded Strain Gauge E 2 E 4 Example Error Calculation Ge...

Page 10: ...nnels G 22 G 2 Static Measurements G 23 G 2 1 1 Hz Measurement Example One CDM VW300 Two Channels G 23 G 2 2 1 Hz Measurement Example One CDM VW305 Eight Channels G 24 Figures 4 1 Two channel CDM VW300 wiring panel 3 4 2 Eight channel CDM VW305 wiring panel 3 4 3 Measurement speeds of the AVW200 and CDM VW300 analyzers 4 4 4 Single coil vibrating wire sensor including coil and thermistor outputs 4...

Page 11: ...ration Report of a Sensor without a Thermistor D 2 F 1 Temperature measurement error at three temperatures as a function of lead length Wire is 22 AWG with 16 ohms per 1000 feet F 2 F 2 Temperature measurement error on a 1000 foot lead Wire is 22 AWG with 16 ohms per 1000 feet F 3 F 3 Temperature measurement error on a 3000 foot lead Wire is 22 AWG with 16 ohms per 1000 feet F 3 F 4 Temperature me...

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Page 13: ... Dynamic Vibrating Wire Analyzers facilitate sub second measurement of vibrating wire sensors These analyzers perform advanced excitation spectral analysis and digital signal processing to obtain high accuracy measurements Data are stored on a Campbell Scientific datalogger which is normally used to control the system in field installations The CDM VW300 has two modes of operation Laboratory mode ...

Page 14: ... for the version number 3 Initial Inspection CDM VW300 series analyzers ship with o 1 each pn 29389 CDM Parts Kit o 1 each ResourceDVD which contains DVWTool and current DevConfig software Upon receipt of the CDM VW300 inspect the packaging and contents for damage File damage claims with the shipping company Thoroughly check all packaging material for product that may be concealed inside it Check ...

Page 15: ...hows 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 Eigh...

Page 16: ...or outputs 4 4 Laboratory Mode Laboratory mode allows for examination and validation of specific measurements types without a datalogger such as might occur before field deployment As shown in Figure 4 5 a connection is made from the CDM VW300 to a personal computer using a USB cable Campbell Scientific DVWTool software on the PC enables observation of sensor outputs and configuration of the CDM V...

Page 17: ...ctural analysis applications Following is a short introduction to the use of data made available by CDM VW300 series analyzers 4 6 1 Static Measurements Each sensor is measured for a static frequency once per second The static frequency is used to obtain a result with finer spectral bin resolution than that which can be achieved at the dynamic measurement rates This measurement can be helpful in d...

Page 18: ...tation bridge The histograms are calculated by the CDM VW300 analyzer to ease the processing burden required of the controlling datalogger CRBasic Help topic for the Rainflow instruction has more information about rainflow histograms 4 6 5 System Diagnostics Several diagnostic values will help you scrutinize basic CDM VW300 measurements Excitation level and low high frequency or amplitude warnings...

Page 19: ...e 5 1 CDM VW300 Datalogger Compatibility Datalogger Connect with SC CPI1 Module Maximum Measurement Rate Hz Maximum CDM VW305 Analyzers at Max Rate Maximum Channels CR3000 1002 1 8 50 3 24 20 6 48 CR800 CR1000 50 1 8 20 4 32 Frequency measurement A vibrating wire circuit is excited and measured through the same coil connection Sinusoidal excitation persists for a few cycles of the wire oscillation...

Page 20: ...Effective Frequency Measurement Resolution4 Sample Rate Hz Noise Level Hz RMS 5 1 0 005 20 0 008 50 0 015 100 0 035 2003 0 11 333 33 0 45 Sustained input voltage without damage 0 5 to 7 1 V Temperature measurement Temperature measurement is available for sensors so equipped Excitation and half bridge measurement circuits are integrated into the CDM VW300 and CDM VW305 analyzers Accuracy 0 15 of re...

Page 21: ...tes available only on PC with fast processor using USB cable in lab mode 4 The effective resolution precision of the output is limited by noise and varies with the sample rate 5 Typical values for a 2 5 kHz resonant sensor 6 Thermistor accuracy and resistance of the wire should be considered as additional errors 6 Installation The CDM VW300 system is designed for use with a PC or as part of a fiel...

Page 22: ...orm this procedure before stepping through the field mode installation procedure of Section 6 2 Field Mode Installation As illustrated in the following figure a connection is made directly between the CDM VW300 and a PC via USB cable No datalogger is required DVWTool support software is used to configure communicate with and obtain sensor readings from the CDM VW300 Figure 6 1 Laboratory mode meas...

Page 23: ...DM VW300 3 Connect a type A male to type micro B male USB cable Campbell Scientific pn 27555 supplied with the analyzer between the CDM VW300 and the PC as shown in Figure 6 3 Reference Section 7 7 1 CDM VW300 to PC Connection Figure 6 3 USB receptacle on CDM VW300 and Type Micro B connector of USB cable Leads from pn 13947 transformer Insert small screwdriver to open gates ...

Page 24: ...e that DVWTool can access the USB connection Reference Section 7 1 2 Using DVWTool Run DVWTool Select CDM VW300 from the Com Port drop down list as indicated in the following figure If COM port CDM VW300 does not appear there is a problem with the installation of the device driver or the creation of the COM port See Section 7 1 1 Software and Driver Installation for remedial steps Press Connect in...

Page 25: ...ed at the right of the channel list as shown in the following figure 5 Check the operating system version of the CDM VW300 Reference Section 7 8 Operating System Operating systems are occasionally updated To ensure the CDM VW300 has the latest search through www campbellsci com downloads for the most recent release Compare the version information on the website with the version shown in the DVWToo...

Page 26: ...Tool is running click Disconnect Remove the 12 Vdc power from the CDM VW300 7 Connect the vibrating wire sensors to the CDM VW300 as shown in the following figures Reference Section 7 7 2 CDM VW300 to Sensor Connection Figure 6 4 Sensor connection on a CDM VW305 ...

Page 27: ...retations Table 6 1 CDM VW300 Status LED States Green or red flash at three second interval Channel is activated Green flash Response received from sensor Red flash Diagnostic flags indicate there may be a problem No flash unlit Channel is not activated 10 Ensure that frequency readings can be obtained from the sensors Reference Section 7 12 2 1 Monitoring with DVWTool Software Click Connect on th...

Page 28: ...is covered in this section Additional details concerning field mode configuration and daisy chaining power and RJ45 connections are discussed in Section 7 System Operation Capacity of the power supply is a critical element of field installations Most field mode installations will require continuous ac power or large solar panels and batteries 6 2 1 Field Mode Installation Equipment The following c...

Page 29: ...struction settings and provides a place to record settings for one sensor Copy and fill in this worksheet for each sensor to be connected Table 6 2 DVWTool and CRBasic Settings DVWTool Setting Corresponding CRBasic Instructions and Parameters Setting Device Name No corresponding setting Scan Scan Rate1 Interval1 No corresponding setting Units msec No corresponding setting Buffer 500 No correspondi...

Page 30: ...asic Scan instruction Interval 1 DVWTool Scan Rate 1000 3 When the laboratory mode installation has been performed on all sensors click Disconnect in the DVWTool window Disconnect or turn off power to the CDM VW300 4 Assemble the datalogger and power supply using Figure 6 7 Field data acquisition system as a guide Do not turn power on until the system is completely assembled 5 A reliable data acqu...

Page 31: ...DM C2 SDM C3 Figure 6 9 Datalogger to SC CPI connection b As shown in Figure 6 10 connect the CDM VW300 to the SC CPI Reference Section 7 7 3 CDM VW300 to SC CPI Connection and Appendix B SC CPI Datalogger to CPI Interface Use the RJ45 CPI cable between the CPI ports of the CDM VW300 and the SC CPI interface Use the yellow tape included in the CPI Network Kit pn 29370 to differentiate a cable used...

Page 32: ...ained Figure 6 11 Install CPI bus terminator 7 As shown in Figure 6 12 connect power leads to the CDM VW300 Do not turn power on until the system is fully assembled Connect dc power to the Power connector on the side of the CDM VW300 Voltages from 10 to 32 Vdc may be used Do not connect ac power directly to the CDM VW300 A convenient power source is the combination of 12V and G terminals on the fa...

Page 33: ... the CDM VW300 and datalogger to earth ground with large gauge wire 14 AWG wire or larger is recommended Reference Section 7 7 5 Earth Ground Connections Figure 6 13 Earth ground connections 9 Write or obtain a CRBasic program for the datalogger Reference Section 7 10 CRBasic Programming and Appendix G CRBasic Program Library ...

Page 34: ...for the CDM VW300 when using a CDM VW305 Configurations for a particular analyzer are deeply rooted in the CRBasic program Simply changing the DeviceType argument will not make all the necessary changes The following figure points out essential elements of the CRBasic program for a datalogger controlling a CDM VW300 To simply confirm that readings can be obtained one of the following example progr...

Page 35: ...ample One CDM VW305 Eight Channels to the following Dim Enable 8 As Long 1 0 0 0 0 0 0 0 If proper frequencies are shown the datalogger has successfully communicated with the CDM VW300 via the SC CPI device and obtained data A permanent data collection program for field operation can now be loaded 7 System Operation IMPORTANT Do not connect the CDM VW300 analyzer or SC CPI interface to a PC until ...

Page 36: ...ist of available COM ports associated with the Connect button in the main screen of DVWTool To correct this problem connect the device to the computer with the USB cable Open the Windows Device Manager Find the placeholder device CDM VW300 or SC CPI identified with a super imposed exclamation point in a yellow bubble box Right click on the device Select Update Driver Software 7 1 2 Using DVWTool T...

Page 37: ... then this field represents the resonant frequency of the vibrating wire sensor If the Output Format field is set to Freq2 this is the square of the resonant frequency In either format the resulting number is modified by the Multiplier and Offset fields before being output to this field Static Frequency Hz or Hz2 represents the same information as the Dynamic Frequency field in all respects except...

Page 38: ...he frequency output of the sensor on that channel 7 1 3 Using DevConfig The Device Configuration Utility DevConfig is a software package that enables a PC to communicate with many Campbell Scientific products It communicates with the CDM VW300 via USB to configure settings and display the output of attached sensors No datalogger is required Data are output to the main window in tabular form Users ...

Page 39: ...lation for remedial steps 7 1 3 2 DevConfig Settings Editor See Table 7 1 Summary of CDM VW300 Configuration Settings for a listing of settings that can be viewed and edited with DevConfig 7 2 Using the Datalogger Outputs from the CDM VW300 are captured by a CR3000 CR1000 or CR800 datalogger via the SC CPI communications interface A custom CRBasic program written to capture and store device output...

Page 40: ...bell Scientific Alternatively if an adequate power supply used with a Campbell Scientific datalogger is available power for the CDM VW300 series analyzer can be drawn from the datalogger wiring panel Figure 7 3 12 Vdc power transformer for laboratory mode installation The transformer sometimes used to provide charging power to a Campbell Scientific PS100 power supply or to a CR3000 datalogger with...

Page 41: ...y and data continuity Contact a Campbell Scientific application engineer for assistance in configuring an adequate power supply 7 5 Configuring the CDM VW300 Analyzer CDM VW300 series analyzers must be configured by the user before sensor measurement will be successful Configuration can be done using DVWTool or DevConfig software or a datalogger CRBasic program See Section 7 1 PC Based Tools for m...

Page 42: ...fig Output Decimation ncs Dynamic sample rate Scan Rate Scan Rate Hz Scan Interval 1 DVWTool Scan Rate 1000 Device type Device Type Device Type CDM_VW300Config DeviceType CPI bus address CPI Address CPI Address CDM_VW300Config CPIAddress System options ncs ncs CDM_VW300Config SysOptions Channels enabled Enable Channel X Enable CDM_VW300Config ChanEnable Desired resonant amplitude Resonant Amplitud...

Page 43: ...F_AmpBins Rainflow Low Limit Rainflow Low Limit CDM_VW300Config RF_LowLim Rainflow High Limit Rainflow High limit CDM_VW300Config RF_HighLim Rainflow Minimum Change Rainflow Min Change CDM_VW300Config RF_Hyst Rainflow Rainflow Form Rainflow Form CDM_VW300Config RF_Form 7 5 1 Device Name This setting specifies an alphanumeric name for the analyzer This is an optional setting and is not available in...

Page 44: ...r is a CDM VW300 Option 0 or CDM VW305 Option 1 7 5 9 CPI Bus Address Each CDM VW300 series analyzer must be given a unique address on the CPI bus using DVWTool or DevConfig software This address is used as the argument in the CPIAddress parameter in the CRBasic program instruction CDM_VW300Config For more information about the operation of the CPI bus see Appendix B SC CPI Datalogger to CPI Inter...

Page 45: ...through other datalogger calculations or by post processing of the data Please refer to the calibration sheet that came with each sensor to understand how the frequency output should be transformed to obtain the desired engineering units Appendix D Digits Conversion and Appendix E Calculating Measurement Error contain additional information about conversion from frequency to engineering units 7 5 ...

Page 46: ...mum measurement conditions 7 6 2 Noise Performance See Section 5 2 Specifications for more information about the noise and accuracy of frequency readings at various sampling rates 7 7 System Connections IMPORTANT Do not connect the CDM VW300 analyzer or SC CPI interface to a PC until AFTER installing DVWTool 1 0 or later or DevConfig 2 04 or later Consult Section 7 1 1 Software and Driver Installa...

Page 47: ...he specifications of a particular sensor to understand the function of each lead Figure 7 5 Three wire vibrating wire sensor leads As illustrated in Figure 7 5 and Figure 7 6 in the three wire configuration two wires are provided as connections to the coil circuit of the sensor The third wire is a shield wire to be connected to ground Most vibrating wire sensors operate equally well with either po...

Page 48: ...cted to the ground connection corresponding to the measurement channel Figure 7 7 Five wire vibrating wire sensors leads For sensors with five lead wires three wires operate as described previously for a three wire configuration The additional two leads are thermistor leads and as illustrated in Figure 7 7 and Figure 7 8 can be wired to the thermistor T channels on the analyzer ...

Page 49: ...the desired engineering units A thermistor is a specialized resistor used for measuring temperature and as such has no polarity 7 7 3 CDM VW300 to SC CPI Connection Connect a CPI cable between the CPI port of the CDM VW300 and the SC CPI interface as shown in Figure 7 9 A standard RJ45 cable such as those used in Ethernet networks may be used Yellow tape included in the CPI Network Kit pn 29370 ca...

Page 50: ...rt of the CDM VW300 as shown in Figure 7 10 Figure 7 10 CPI terminator installed Apply power to the CDM VW300 the datalogger and the SC CPI interface to confirm connectivity Multiple CDM VW300 analyzers can be connected to the CPI bus The following figure shows these connections The last open CPI port should have a CPI terminator installed Connect SC CPI to CDM VW300 RJ 45 to RJ 45 ...

Page 51: ...er to the Power In connector on the side of the CDM VW300 Power supplies providing voltages from 9 6 to 32 Vdc with a minimum 200 mA current rating may be used Connect dc power to the CDM VW300 as illustrated in the following figure SC CPI interface Daisy chained CPI cables Daisy chained power leads CPI terminator ...

Page 52: ...ling 12 Vdc transformer on the CDM VW300 In field mode installations power is connected and daisy chained as shown in the following figures Figure 7 13 Daisy chaining 12 Vdc power input on the CDM VW300 Leads from pn 13947 transformer Insert small screwdriver to open gates ...

Page 53: ... 45 simultaneously When connecting to a CDM VW300 analyzer that is active via CPI in this way the device settings are locked The settings shown in DVWTool will reflect the settings that were configured on the device by the datalogger CRBasic program using the CDM_VW300Config instruction Even if the interface of the DVWTool software appears to make a change to one of these locked settings it will n...

Page 54: ...on 1 CDM VW305 100 Hz 8 channels on 1 CDM VW305 Not supported Not supported These channel counts predict best case scenarios wherein no other measurements are made on the dataloggers Additional measurements will likely reduce the channel counts Note that each analyzer uses the bandwidth of the full channel compliment whether or not all channels are active For example consider a CR3000 datalogger c...

Page 55: ...analyzers the datalogger and the SC CPI interface simultaneously If powering devices sequentially is necessary first switch power to each analyzer The COMM Status LED on each analyzer will flash orange meaning that the device has not yet established a connection with the SC CPI Next switch power to the datalogger and the SC CPI The SC CPI will begin initializing the CPI network The COMM Status lig...

Page 56: ...00 0 is the Scan instruction with arguments set for a 20 Hz CDM VW300 scan rate Table 7 4 lists other scan matches Table 7 4 CDM VW300 Scan Rate Datalogger Scan Interval Pairings CDM VW300 Scan Rate Datalogger Scan Interval 20 Hz 50 ms 50 Hz 20 ms 100 Hz 10 ms The CR3000 CR1000 and CR800 dataloggers do not support operation of the CDM VW300 in 200 and 333 3 Hz modes CDM_VW300Dynamic captures dynam...

Page 57: ...s over the active communications link DevConfig PC400 LoggerNet RTDAQ In addition the following portable memory devices have provisions for transferring programs from a PC to the datalogger CompactFlash CF card with CFM100 or NL115 CompactFlash Modules SC115 CS I O 2G Flash Memory Drive with USB Interface 7 11 System Adjustments 7 11 1 Frequency Range Assuming a reasonable level of certainty about...

Page 58: ...designated as active for measurement For more detail on how to activate individual channels for measurement see Section 7 1 2 Using DVWTool or Section 7 1 3 Using DevConfig 7 12 2 Monitoring System Performance RTDAQ or LoggerNet software is typically used to monitor system performance For complete information about using these software consult the associated Help or respective manuals which are av...

Page 59: ...User Manual 47 Figure 7 16 LoggerNet connect screens showing frequencies from CDM VW300 ...

Page 60: ...howing the datalogger has successfully communicated with the CDM VW300 and obtained data 7 12 2 1 Monitoring with DVWTool Software The Dynamic Vibrating Wire Tool Box DVWTool is a software package that enables a PC to communicate with the CDM VW300 via USB no datalogger required configure CDM VW300 settings and display the output of attached ...

Page 61: ...may drop briefly until the excitation mechanism can insert energy at the new frequency The result is that a low amplitude diagnostic condition may appear for a short time This is expected behavior Low and high amplitude diagnostic codes that appear briefly are usually no cause for concern For these instances there is no loss of fidelity in the values measured by the analyzer However low and high a...

Page 62: ...roblem likely resides with the datalogger Otherwise the problem likely resides with the CDM VW300 analyzer or the sensors 3 With the datalogger and CDM VW300 still disconnected send a CRBasic program to the datalogger that measures only panel temperature and battery voltage CRBasic Editor defaults to this type of program Ensure that those readings are correct and can be viewed with RTDAQ or Logger...

Page 63: ...oned up to a number equal to the maximum number of channels of the analyzer For example when the CDM VW305 is measuring eight channels at 100 Hz the diagnostic code array should be dimensioned to 8 Each variable in the array receives 100 diagnostic codes per second or one diagnostic code for each measurement In total 800 diagnostic codes are received each second 8 5 1 1 Description of Diagnostic P...

Page 64: ...ting wire falls between the Actual Max Freq Hz shown in DVWTool and the Maximum Frequency Hz entered in DVWTool The CDM_VW300Config instruction equivalent to Maximum Frequency Hz is the HighFreq parameter When a high frequency limit is entered into DVWTool or the CRBasic program an error window is created that spans the bandwidth between the frequency cut off requested Maximum Frequency or HighFre...

Page 65: ...or high frequency warning flag can be set for any one measurement but not both Any one amplitude flag and any one frequency flag can be set simultaneously 8 5 1 4 Decoding the Diagnostic Code To recover the five diagnostic parameters from a diagnostic code the bit pattern represented by the twelve least significant bits of the 32 bit diagnostic code is decoded 8 5 1 4 1 Excitation Strength The eig...

Page 66: ...igh amplitude warning flag Use the following expression to isolate the state of this bit DiagCode AND 512 Similar techniques to those described in the preceding section for the low amplitude warning flag can be used with this expression 8 5 1 4 4 Low Frequency Warning Flag The eleventh bit 210 or 1024 corresponds to the low frequency warning flag and can be isolated with the expression DiagCode AN...

Page 67: ...91 Subtract 1536 from 1650 and divide the result 114 the result will always fall between 0 and 255 by 42 5 The result is 2 68 V Ranges outside those listed in Table 8 2 Diagnostic Code Ranges should only occur in conjunction with hardware or operational errors reported by the datalogger 8 5 2 Standard Deviation of Dynamic Output A 1 Hz calculation of standard deviation from an array of dynamic rea...

Page 68: ...nterface are automatically sent to the PC running Windows XP Windows Vista Windows 7 or Windows 8 operating system DVWTool Dynamic Vibrating Wire Tool software It was specifically written to support CDM VW300 series analyzers DVWTool enables a PC to initiate and request measurements from the CDM VW300 without use of a datalogger When DVWTool is installed USB drivers for CDM VW300 series analyzers ...

Page 69: ... are either registered trademarks or trademarks of Microsoft Corporation in the United States and or other countries Geokon 4000 and Geokon 4420 are products of Geokon Inc CompactFlash is a registered trademark of the SanDisk Corporation ...

Page 70: ...CDM VW300 Series Dynamic Vibrating Wire Analyzers 58 ...

Page 71: ...s compress the measurement cycle and achieve much higher sample rates by eliminating the broadband excitation and not allowing the wire oscillation to decay Figure A 1 Timing of dynamic vibrating wire measurements illustrates the timing of this process If energy can be injected into the oscillation at precisely the right frequency and with the correct phase then a very short excitation waveform wi...

Page 72: ...hronization is another important benefit when correlating measurements from multiple sensors Time synchronized excitation control is a key differentiator between this approach and other auto resonant coil excitation methods A 1 1 Dynamic and Static Frequencies CDM VW300 series analyzers output a dynamic frequency value for each sensor at the rates of 20 50 100 200 or 333 3 Hz A static frequency is...

Page 73: ... and C3 There are two LED indicator lights on the SC CPI module The indicator lights show status of the link and give a visual indication that it is operating correctly The LED closest to the CPI port shows status of the CPI bus The LED closest to the terminal block shows status of the serial connection to the datalogger Connection to the datalogger consists of connecting 12V and G terminals of on...

Page 74: ...n and examine other settings and operational statistics such as CPI communication diagnostics Serial or CPI load CPI frame errors CPI network information Figure B 1 Connection to the SC CPI in DevConfig Refer to the help window in the DevConfig Settings Editor tab for further details about operations that can be performed and information that is available ...

Page 75: ...o 50 C 55 to 85 C optional Power requirement Source 9 6 to 16 Vdc Load 50 mA continuous Connectors CPI to CDM RJ45 Serial to datalogger Screw terminal Serial to PC Type micro B male USB Certification Tested in accordance to EM directive 2004 108 EC and BS EN61326 2006 Weight 0 188 kg 0 415 lb Dimensions 15 94 x 7 49 x 3 18 cm 6 28 x 2 95 x 1 25 in ...

Page 76: ...Appendix B SC CPI Datalogger to CPI Interface B 4 ...

Page 77: ... may come from the datalogger power source or through the datalogger wiring panel C 1 2 Interconnect Cable Current Campbell Scientific dataloggers require the SC CPI Interface to connect with one or more CDM devices Cat5e cable with RJ45 terminations connects a CDM devices with the SC CPI and other CDM devices Cabling and connections must be managed carefully to achieve the highest data rates and ...

Page 78: ...ith a CPI Bit Rate setting of Auto Detect1 Doing so allows the bit rate to be controlled by either the CPISpeed CRBasic instruction or the CPI Bit Rate setting of the SC CPI interface1 The CPISpeed setting takes priority When a CDM device is set to Auto Detect it initializes into the mode given to it by the SC CPI interface which comes from either the SC CPI setting or the CPISpeed instruction Any...

Page 79: ...tributed Architecture CDM devices can operate with longer cable distances between modules and the datalogger than might be expected for sub second data acquisition A common long cable network is illustrated in the following Figure C 2 The CDM VW300 uses the CPI communications protocol to communicate with Campbell Scientific dataloggers or other CDM devices Two CPI connectors are provided on each d...

Page 80: ...Appendix C CDM Devices and CPI Bus C 4 Figure C 2 Long cable lengths of a distributed CPI bus ...

Page 81: ...omial fit data from the calibration report to then convert digits to engineering units Following is an example that converts the frequency output of the CDM VW300 first to digits then to engineering units of millimetres of displacement D 1 Example Frequency to Digits to Displacement Measuring a Geokon vibrating wire displacement sensor the CDM VW300 analyzer outputs a value of 2400 Hz Figure D 1 s...

Page 82: ...Appendix D Digits Conversion D 2 Figure D 1 Geokon Calibration Report of a Sensor without a Thermistor ...

Page 83: ... the present frequency on the wire Use Eq 2 together with noise levels N Hz RMS found in Table 5 3 CDM VW300 305 Effective Frequency Measurement Resolution to calculate the effective resolution Re of a measurement For a specific sample rate in Table 5 3 use the corresponding value of N in place of f Eq 2 can then be expressed as Re 2KfN Eq 3 E 1 Example Error Calculation Geokon Strain Gauge When u...

Page 84: ...ve resolution the constant C does not vary with frequency so it can be ignored for the very small changes in frequency that are of concern The formula becomes µε 2AfN E 4 Example Error Calculation Geokon 4420 Crack Meter The displacement s measured by the crack meter is given by the formula s Gf2 1000 Kt where G is the linear gauge factor K is a thermal factor and t is the temperature of the senso...

Page 85: ...lation DGSI Piezometer 52611099 For Durham Geo Slope Indicator piezometer 52611099 when using gauge factors A B and C the formula for pressure P derived from frequency is given as P Af2 Bf C The resulting noise effective resolution formula is then P 2Af B N or P 2AfN BN ...

Page 86: ...Appendix E Calculating Measurement Error E 4 ...

Page 87: ...sensor manufacturer Please contact the sensor manufacturer to get coefficients for a specific thermistor F 1 1 Resistance Conversion Example Geokon Sensor If the coefficients for the Steinhart Hart equation are as follows A 1 4051E 03 B 2 369E 04 C 1 019E 07 The equation for converting the resistance measurement to degrees Celsius is Temperature 1 1 4051E 03 2 369E 04 LN resistance 1 019E 07 LN re...

Page 88: ...and its effect can be removed by the initial calibration Errors caused by the change in wire resistance due to temperature and thermistor interchangeability are not removed by the initial calibration Figure F 1 through Figure F 4 show how wire resistance affects the temperature measurement for a Geokon 4500 vibrating wire piezometer Figure F 1 Temperature measurement error at three temperatures as...

Page 89: ... Information F 3 Figure F 2 Temperature measurement error on a 1000 foot lead Wire is 22 AWG with 16 ohms per 1000 feet Figure F 3 Temperature measurement error on a 3000 foot lead Wire is 22 AWG with 16 ohms per 1000 feet ...

Page 90: ...Appendix F Thermistor Information F 4 Figure F 4 Temperature measurement error on a 5000 foot Lead Wire is 22 AWG with 16 ohms per 1000 feet ...

Page 91: ...c frequencies Public Diag 2 As Long diagnostic code Public StaticFreq 2 Static 1 Hz output frequencies Public Therm 2 Thermistor readings Standard Deviation of the dynamic readings that occurred during the latest one second interval Public DynStdDev 2 The following arrays are used to configure the CDM VW300 Refer to the CDM_VW300Config instruction used below CH1 CH2 Set to true Enabled 1 Disabled ...

Page 92: ...econd CDM_VW300Static CPI_ADDR StaticFreq Therm DynStdDev Get static readings CallTable static EndIf NextScan EndProg G 1 2 20 Hz Measurement Example One CDM VW305 Eight Channels 20Hz 1Device8Ch_4 25 CR3000 datalogger CDM VW305 vibrating wire analyzer Program to read 20 Hz dynamic data from one CDM VW305 analyzer measuring eight channels IMPORTANT Ensure that the CPI address coded on the following...

Page 93: ...g 100 100 100 100 100 100 100 100 Configure the CDM VW300 series device Use the variable arrays declared above CDM_VW300Config 1 CPI_ADDR 0 Enable Max_AMP F_Low F_High _ OutForm Mult Off SteinA SteinB SteinC _ RFMB RFAB RFLL RFHL RFHY RFOF DataTable static true 1 Static Frequency reading 1Hz output Sample 8 StaticFreq IEEE4 Thermistor reading Ohms or DegC Sample 8 Therm IEEE4 Standard Deviation of...

Page 94: ...00 6000 Dim OutForm3 8 As Long 0 0 0 0 0 0 0 0 Dim Mult3 8 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 Dim Off3 8 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Dim SteinA3 8 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Dim SteinB3 8 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Dim SteinC3 8 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Shared rainflow configuration not used but required as configuration arguments Dim RFMB 8 As Long 20 20 20 20 20 20 20 20 Dim RF...

Page 95: ...requencies Public StaticFreq4 8 StaticFreq5 8 StaticFreq6 8 Public Therm1 8 Therm2 8 Therm3 8 Thermistor readings Public Therm4 8 Therm5 8 Therm6 8 Public DynStdDev1 8 DynStdDev2 8 DynStdDev3 8 Dynamic standard deviations Public DynStdDev4 8 DynStdDev5 8 DynStdDev6 8 Setup for First Device CH1 CH2 CH3 CH4 CH5 CH6 CH7 CH8 Dim Enable1 8 As Long 1 1 1 1 1 1 1 1 Dim Max_AMP1 8 0 002 0 002 0 002 0 002 ...

Page 96: ... Dim Off6 8 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Dim SteinA6 8 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Dim SteinB6 8 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Dim SteinC6 8 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Shared rainflow configuration not used but required as configuration arguments Dim RFMB 8 As Long 20 20 20 20 20 20 20 20 Dim RFAB 8 As Long 20 20 20 20 20 20 20 20 Dim RFLL 8 400 0 400 0 400 0 400 0 400 0 400 0 400 0 ...

Page 97: ...M_VW300Static CPI_ADDR2 StaticFreq2 Therm2 DynStdDev2 CDM_VW300Static CPI_ADDR3 StaticFreq3 Therm3 DynStdDev3 CDM_VW300Static CPI_ADDR4 StaticFreq4 Therm4 DynStdDev4 CDM_VW300Static CPI_ADDR5 StaticFreq5 Therm5 DynStdDev5 CDM_VW300Static CPI_ADDR6 StaticFreq6 Therm6 DynStdDev6 CallTable static EndIf NextScan EndProg G 1 5 50 Hz Measurement Example One CDM VW300 Two Channels 50Hz 1Device2Ch_4 25 13...

Page 98: ...0 0 Dim SteinB 2 0 0 0 0 Dim SteinC 2 0 0 0 0 Rainflow configuration not used in this program but required as configuration arguments 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 Configure the CDM VW300 series device Use the variable arrays declared above CDM_VW300Config 0 CPI_ADDR 0 Enable Max_A...

Page 99: ...6000 6000 6000 Output Format Hz vs Hz 2 Value of 0 measured frequency is given in units of Hz Value of 1 measured frequency is squared and given in units of Hz 2 Dim OutForm 8 As Long 0 0 0 0 0 0 0 0 Multiplier factor to be applied to sensor output frequency Dim Mult 8 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 Offset shift to be applied to sensor output frequency Dim Off 8 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 St...

Page 100: ...0 0 0 Dim Mult1 8 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 Dim Off1 8 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Dim SteinA1 8 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Dim SteinB1 8 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Dim SteinC1 8 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Setup for Second Device Dim Enable2 8 As Long 1 1 1 1 1 1 1 1 Dim Max_AMP2 8 0 002 0 002 0 002 0 002 0 002 0 002 0 002 0 002 Dim F_Low2 8 300 300 300 300 300 300 300 300...

Page 101: ...g 50 Hz 20msec scan rate Scan 20 msec 500 0 CDM_VW300Dynamic CPI_ADDR1 Freq1 Diag1 Get dynamic readings CDM_VW300Dynamic CPI_ADDR2 Freq2 Diag2 CDM_VW300Dynamic CPI_ADDR3 Freq3 Diag3 CallTable dynamic If TimeIntoInterval 0 1 Sec Then CDM_VW300Static CPI_ADDR1 StaticFreq1 Therm1 DynStdDev1 Get static readings CDM_VW300Static CPI_ADDR2 StaticFreq2 Therm2 DynStdDev2 CDM_VW300Static CPI_ADDR3 StaticFre...

Page 102: ... bin C 0 Open form Include outside range values in end bins C 1 Closed form Exclude values outside range CDM_VW300Config 0 CPI_ADDR 0 Enable Max_AMP F_Low F_High _ OutForm Mult Off SteinA SteinB SteinC _ RF_mean_bins RF_amp_bins RF_Lo_lim _ RF_Hi_lim RF_Hyst RF_OutForm DataTable static true 1 Sample 2 StaticFreq IEEE4 Sample 2 Therm IEEE4 Sample 2 DynStdDev IEEE4 EndTable DataTable dynamic true 1 ...

Page 103: ... 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Rainflow Histogram configuration Dim RF_mean_bins 8 As Long MBINS MBINS MBINS MBINS MBINS MBINS MBINS MBINS Mean Bins Dim RF_amp_bins 8 As Long ABINS ABINS ABINS ABINS ABINS ABINS ABINS ABINS Amplitude Bins Dim RF_Lo_lim 8 400 0 400 0 400 0 400 0 400 0 400 0 400 0 400 0 Low Limit Dim RF_Hi_lim 8 4000 0 4000 0 4000 0 4000 0 4000 0 4000 0 4000 0 4000 0 High Limit Dim R...

Page 104: ...ided with sensors 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 m...

Page 105: ...le dynamic true 1 Sample 2 Strain IEEE4 Sample 2 DCode IEEE4 Sample 2 ExciteStr IEEE4 EndTable DataTable CalHist NewFieldCal 1 SampleFieldCal EndTable BeginProg 50 Hz 20msec scan rate Scan 20 msec 500 0 CDM_VW300Dynamic CPI_ADDR Strain DCode Get unshifted strain Now shift the given Strain using the Baseline Offset value Strain 1 Strain 1 StrainBL 1 Strain 2 Strain 2 StrainBL 2 Zeroing calibration ...

Page 106: ...rostrain 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 Stat...

Page 107: ... Temp 2 0 TempBL ZeroMode 0 1 100 CallTable dynamic CallTable CalHist 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 ...

Page 108: ...ticFreq 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...

Page 109: ...bleFile_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 Write data to CF card at each event Demonstrate use of TableFile with Option 64 DataEvent and DataInterval to conserve data storage IMPORTANT Ensure that the CPI address coded on the following line matches the address reported for the...

Page 110: ...ash device TableFile CRD Status StationName 1 1 TFStatic _ 64 1 0 15 Min NewStaticFileStored LastStaticFileName Average 2 StaticStrain IEEE4 False Average 2 Temp IEEE4 False Average 2 StrainStdDev IEEE4 False EndTable DataTable dynamic true 1 Using DataEvent only store data in this table when the Microstrain reading is greater than 200 on either channel DataEvent 100 Strain 1 200 OR Strain 2 200 1...

Page 111: ...at which the sensor will be maintained via excitation given in Volts This should be in the range 0 010 to 0 001 Dim Max_AMP 2 0 002 0 002 Low Frequency Boundary sensor frequency should never fall below this value regardless of environmental changes Dim F_Low 2 300 300 High Frequency Boundary sensor frequency should never exceed this value regardless of environmental changes Dim F_High 2 6000 6000 ...

Page 112: ...he CDM VW300 series device Refer to the CDM_VW300Config instruction used below CH1 CH2 CH3 CH4 CH5 CH6 CH7 CH8 Set to true Enabled 1 Disabled 0 only those channels which have sensors connected Dim Enable 8 As Long 1 1 1 1 1 1 1 1 Specify the target desired resonant amplitude at which the sensor will be maintained via excitation given in volts This should be in the range 0 010 to 0 001 Dim Max_AMP ...

Page 113: ...ate Scan 10 msec 500 0 CDM_VW300Dynamic CPI_ADDR Freq Diag Get dynamic readings CallTable dynamic If TimeIntoInterval 0 1 Sec Then Process static data only once per second CDM_VW300Static CPI_ADDR StaticFreq Therm DynStdDev Get static readings CallTable static EndIf NextScan EndProg G 2 Static Measurements G 2 1 1 Hz Measurement Example One CDM VW300 Two Channels 1Hz 1Device2Ch_3 25 13 CR3 CR3000 ...

Page 114: ...he DevConfig or DVWTool software Const CPI_ADDR 1 SET CPI ADDRESS HERE Public StaticFreq 8 Static 1 Hz output frequencies Public Therm 8 Thermistor readings Dim Freq 8 dynamic instruction is required Dim Diag 8 As Long Dim DynStdDev 8 Dim Enable 8 As Long 1 1 1 1 1 1 1 1 Dim Max_AMP 8 0 002 0 002 0 002 0 002 0 002 0 002 0 002 0 002 Dim F_Low 8 300 300 300 300 300 300 300 300 Dim F_High 8 6000 6000...

Page 115: ...e is required Scan 50 msec 500 0 CDM_VW300Dynamic CPI_ADDR Freq Diag dynamic instruction is required If TimeIntoInterval 0 1 Sec Then Process static data once per second CDM_VW300Static CPI_ADDR StaticFreq Therm DynStdDev Get static readings CallTable static EndIf NextScan EndProg ...

Page 116: ...Appendix G CRBasic Program Library G 26 ...

Page 117: ...Appendix G CRBasic Program Library G 27 ...

Page 118: ...lberta T5M 1W7 CANADA www campbellsci ca dataloggers campbellsci ca Campbell Scientific Centro Caribe S A CSCC 300N Cementerio Edificio Breller Santo Domingo Heredia 40305 COSTA RICA www campbellsci cc info campbellsci cc Campbell Scientific Ltd CSL Campbell Park 80 Hathern Road Shepshed Loughborough LE12 9GX UNITED KINGDOM www campbellsci co uk sales campbellsci co uk Campbell Scientific Ltd Fran...

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