Campbell CDM-VW300 Series User Manual

USER MANUAL

Issued: 29.10.13

Copyright © 2013 Campbell Scientific Inc.

Printed under licence by Campbell Scientific Ltd.

CSL 995

CDM-VW300 Series

Dynamic Vibrating-Wire

Analyzers

Guarantee

This equipment is guaranteed against defects in materials and workmanship.
This guarantee applies for twelve months from date of delivery. We will repair
or replace products which prove to be defective during the guarantee period
provided they are returned to us prepaid. The guarantee will not apply to:



Equipment which has been modified or altered in any way without the

written permission of Campbell Scientific



Batteries



Any product which has been subjected to misuse, neglect, acts of God or

damage in transit.

Campbell Scientific will return guaranteed equipment by surface carrier
prepaid. Campbell Scientific will not reimburse the claimant for costs incurred

in removing and/or reinstalling equipment. This guarantee and the Company’s

obligation thereunder is in lieu of all other guarantees, expressed or implied,
including those of suitability and fitness for a particular purpose. Campbell
Scientific is not liable for consequential damage.

Please inform us before returning equipment and obtain a Repair Reference
Number whether the 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 Material and Decontamination” form will be issued

for completion.

When returning equipment, the Repair Reference Number must be clearly

marked on the outside of the package. Complete the “Declaration of

Hazardous Material and Decontamination” form and ensure a completed copy
is returned with your goods. Please note your Repair may not be processed if
you do not include a copy of this form and Campbell Scientific Ltd reserves
the right to return goods at the customers’ expense.

Note that goods sent air freight are subject to Customs clearance fees which
Campbell Scientific will charge to customers. In many cases, these charges are
greater than the cost of the repair.

Campbell Scientific Ltd,

Campbell Park, 80 Hathern Road,

Shepshed, Loughborough, LE12 9GX, UK

Tel: [phone]

Fax: [phone]

Email: [e-mail]

www.campbellsci.co.uk

PLEASE READ FIRST

About this manual

Please note that this manual was originally produced by Campbell Scientific Inc. primarily for the
North American market. Some spellings, weights and measures may reflect this origin.

Some useful conversion factors:

Area: 1 in2 (square inch) = 645 mm2

Length: 1 in. (inch) = 25.4 mm

1 ft (foot) = 304.8 mm
1 yard = 0.914 m
1 mile = 1.609 km

Mass: 1 oz. (ounce) = 28.35 g
1 lb (pound weight) = 0.454 kg

Pressure: 1 psi (lb/in2) = 68.95 mb

Volume: 1 UK pint = 568.3 ml

1 UK gallon = 4.546 litres
1 US gallon = 3.785 litres

In addition, while most of the information in the manual is correct for all countries, certain information
is specific to the North American market and so may not be applicable to European users.

Differences include the U.S standard external power supply details where some information (for
example the AC transformer input voltage) will not be applicable for British/European use. Please note,

however, that when a power supply adapter is ordered it will be suitable for use in your country.

Reference to some radio transmitters, digital 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
special installations. Please quote the full part number with the # when ordering.

Recycling information

At the end of this product’s life it should not be put in commercial or domestic refuse
but sent for recycling. Any batteries contained within the product or used during the
products life should be removed from the product and also be sent to an appropriate
recycling facility.

Campbell Scientific Ltd can advise on the recycling of the equipment and in some cases
arrange collection and the correct disposal of it, although charges may apply for some

items or territories.

For further advice or support, please contact Campbell Scientific Ltd, or your local agent.

Campbell Scientific Ltd, Campbell Park, 80 Hathern Road, Shepshed, Loughborough, LE12 9GX, UK

Tel: [phone] Fax: [phone]

Email: [e-mail]

www.campbellsci.co.uk

i

Contents

PDF viewers: These page numbers refer to the printed version of this document. Use the
PDF reader bookmarks tab for links to specific sections.

1. Introduction ................................................................ 1

2. Cautionary Statements .............................................. 2

3. Initial Inspection ........................................................ 2

4. Overview ..................................................................... 2

4.1 Channel Allocations ............................................................................. 3

4.2 Measurement Rates .............................................................................. 3

4.3 Integrated Thermistor Measurement .................................................... 4

4.4 Laboratory Mode .................................................................................. 4

4.5 Field Mode ........................................................................................... 5

4.6 Data Uses ............................................................................................. 5

4.6.1 Static Measurements ..................................................................... 5

4.6.2 Dynamic Measurements ................................................................ 5

4.6.3 Thermistor Measurements ............................................................. 6

4.6.4 Rainflow Histograms .................................................................... 6

4.6.5 System Diagnostics ....................................................................... 6

5. Specifications ............................................................ 6

5.1 Features ................................................................................................ 6

5.2 Specifications ....................................................................................... 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 Connection is Active ............................................ 24

7.1.2.2 DVWTool Settings Editor ................................................ 25

7.1.2.3 Button and Field Descriptions .......................................... 25

7.1.3 Using DevConfig ........................................................................ 26

7.1.3.1 Ensure Connection is Active ............................................ 26

7.1.3.2 DevConfig Settings Editor ............................................... 27

7.2 Using the Datalogger .......................................................................... 27

7.3 Using the SC-CPI Interface ................................................................ 28

7.4 Using Power Supplies ........................................................................ 28

7.4.1 CDM-VW300 Series Analyzer Power ........................................ 28

7.4.2 Data-Acquisition System Power ................................................. 28

ii

7.5 Configuring the CDM-VW300 Analyzer ........................................... 29

7.5.1 Device Name ............................................................................... 31

7.5.2 CPI Bus Speed ............................................................................ 31

7.5.3 Operating System Version .......................................................... 31

7.5.4 Operating System Date ............................................................... 32

7.5.5 Analyzer Serial Number ............................................................. 32

7.5.6 Display Rate ................................................................................ 32

7.5.7 Dynamic Sample Rate ................................................................. 32

7.5.8 Device Type ................................................................................ 32

7.5.9 CPI Bus Address ......................................................................... 32

7.5.10 System Options ........................................................................... 32

7.5.11 Channels Enabled........................................................................ 32

7.5.12 Desired Resonant Amplitude ...................................................... 33

7.5.13 Minimum- and Maximum Cut-Off Frequencies ......................... 33

7.5.14 Frequency-Output Format ........................................................... 33

7.5.15 Multipliers and Offsets ............................................................... 33

7.5.16 Steinhart-Hart Coefficients ......................................................... 33

7.5.17 Rainflow-Histogram Output Configurations ............................... 33

7.6 Sensor Selection ................................................................................. 33

7.6.1 Frequency Considerations ........................................................... 34

7.6.2 Noise Performance ...................................................................... 34

7.7 System Connections ........................................................................... 34

7.7.1 CDM-VW300 to PC Connection ................................................ 34

7.7.2 CDM-VW300 to Sensor Connection .......................................... 35

7.7.3 CDM-VW300 to SC-CPI Connection ......................................... 37

7.7.4 CDM-VW300 to Power Connection ........................................... 39

7.7.5 Earth Ground 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 System Validation .............................................................................. 46

7.12.1 Sensor Validation ........................................................................ 46

7.12.2 Monitoring System Performance ................................................ 46

7.12.2.1 Monitoring with DVWTool Software .............................. 48

7.12.2.1.1 Fault Detection ...................................................... 49

8. Troubleshooting ...................................................... 49

8.1 Connections ........................................................................................ 50

8.2 Power ................................................................................................. 50

8.3 Isolating Components ........................................................................ 50

8.4 Filtering Harmonics ........................................................................... 50

8.5 Diagnostic Outputs ............................................................................. 51

8.5.1 Diagnostic Codes (Dynamic) ...................................................... 51

8.5.1.1 Description of Diagnostic Parameters .............................. 51

8.5.1.2 Calculating Low- and High-Frequency Boundaries ......... 52

8.5.1.3 Using Diagnostic Parameters ........................................... 53

8.5.1.4 Decoding the Diagnostic Code ......................................... 53

8.5.1.4.1 Excitation Strength ................................................ 53

8.5.1.4.2 Low-Amplitude Warning Flag .............................. 53

8.5.1.4.3 High-Amplitude Warning Flag .............................. 54

8.5.1.4.4 Low-Frequency Warning Flag ............................... 54

iii

8.5.1.4.5 High-Frequency Warning Flag .............................. 54

8.5.1.4.6 Interpreting the Diagnostic Code ........................... 54

8.5.2 Standard Deviation of Dynamic Output ...................................... 55

8.6 Factory Default Reset ......................................................................... 55

9. Glossary ................................................................... 56

10. References and Attributions ................................... 56

Appendices

A. Measurement Theory ............................................. A-1

A.1 Dynamic Vibrating-Wire Measurements ........................................ A-1

A.1.1 Dynamic and Static Frequencies .............................................. A-2

B. SC-CPI Datalogger to CPI Interface ...................... B-1

B.1 Introduction ...................................................................................... B-1

B.2 Quickstart ......................................................................................... B-1

B.3 Overview .......................................................................................... B-1

B.4 Specifications ................................................................................... B-3

C. CDM Devices and CPI Bus .................................... C-1

C.1 CDM Interconnection and Datalogger Connection .......................... C-1

C.1.1 Power ........................................................................................ C-1

C.1.2 Interconnect Cable .................................................................... C-1

C.1.3 Speed as a Function of Distance ............................................... C-2

C.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: Geokon 4420 Crack Meter .................. E-2

E.5 Example Error Calculation: DGSI Piezometer 52611099 ................ E-3

F. Thermistor Information .......................................... F-1

F.1 Converting Resistance to Temperature ............................................ F-1

F.1.1 Resistance Conversion Example – Geokon Sensor ................... F-1

F.2 Accuracy and Resolution ................................................................. F-1

G. CRBasic Program Library ..................................... G-1

G.1 Dynamic Measurements ................................................................ .. G-1

G.1.1 20 Hz Measurement Example — One CDM-VW300, Two Channels

.............................................................................................. G-1

G.1.2 20 Hz Measurement Example — One CDM-VW305, Eight Channels

.............................................................................................. G-2

iv

G.1.3 20 Hz Measurement Example — Three CDM-VW305s, 24 Channels

............................................................................................... G-3

G.1.4 20 Hz Measurement Example — Six CDM-VW305s, 48

Channels ................................................................................ G-5

G.1.5 50 Hz Measurement Example — One CDM-VW300, Two Channels

............................................................................................... G-7

G.1.6 50 Hz Measurement Example — One CDM-VW305, Eight Channels

............................................................................................... G-9

G.1.7 50 Hz Measurement Example — Three CDM-VW305s, 24 Channels

............................................................................................. G-10

G.1.8 50 Hz Measurement Example — One CDM-VW300, Two Channels,

Rainflow Histogram ............................................................ G-11

G.1.9 50 Hz Measurement Example — One CDM-VW305, Eight Channels,

Rainflow Histogram ............................................................ G-12

G.1.10 50 Hz Diagnostic Example — One CDM-VW300, Two

Geokon 4000 Sensors with FieldCal()................................. G-14

G.1.11 50 Hz Measurement Example — One CDM-VW300, Two

Geokon 4000 Sensors with FieldCal()................................. G-16

G.1.12 50 Hz Measurement Example — One CDM-VW300, Two

Geokon 4000 Sensors with FieldCal() and CardOut() to

CF ........................................................................................ G-18

G.1.13 50 Hz Measurement Example — One CDM-VW300, Two

Geokon 4000 Sensors with FieldCal() and TableFile() to

CF ........................................................................................ G-19

G.1.14 100 Hz Measurement Example — One CDM-VW300, Two Channels

............................................................................................. G-21

G.1.15 100 Hz Measurement Example — One CDM-VW305,

Eight Channels .................................................................... 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

4-5. Laboratory-mode measurement system diagram................................ .. 5

4-6. Field-mode data-acquisition system diagram ....................................... 5

6-1. Laboratory-mode measurement system.............................................. 10

6-2. 12 Vdc power connection on the CDM-VW300 ................................ 11

6-3. USB receptacle on CDM-VW300 and Type-Micro-B connector

of USB cable .................................................................................. 11

6-4. Sensor connection on a CDM-VW305 ............................................... 14

6-5. Three-wire vibrating-wire sensor connections ................................... 15

6-6. Five-wire vibrating-wire sensor connections ..................................... 15

6-7. Field data-acquisition system ............................................................. 17

6-8. CPI communications links ................................................................. 19

6-9. Datalogger to SC-CPI connection ...................................................... 19

6-10. Connecting the CPI ports of the SC-CPI and CDM-VW300 ............. 20

6-11. Install CPI bus terminator .................................................................. 20

6-12. Power connection ............................................................................... 21

6-13. Earth ground connections ................................................................... 21

7-1. DVWTool Settings Editor and Data Display ..................................... 25

7-2. DevConfig Settings Editor ................................................................. 27

7-3. 12 Vdc power transformer for laboratory-mode installation .............. 28

v

7-4. USB port on the CDM-VW300 .......................................................... 35

7-5. Three-wire vibrating-wire sensor leads .............................................. 35

7-6. Three-wire vibrating-wire sensor connection ..................................... 36

7-7. Five-wire, vibrating-wire sensors leads .............................................. 36

7-8. Five-wire vibrating-wire sensor connection ....................................... 37

7-9. SC-CPI and CDM-VW300 CPI ports with RJ45 cable marked

with yellow tape.............................................................................. 38

7-10. CPI terminator installed ..................................................................... 38

7-11. Multiple analyzers on a CPI bus ........................................................ 39

7-12. Installing 12 Vdc transformer on the CDM-VW300 .......................... 40

7-13. Daisy-chaining 12 Vdc power input on the CDM-VW300 ................ 40

7-14. Earth ground connections ................................................................... 41

7-15. CR3000 and SC-CPI connections ...................................................... 42

7-16. LoggerNet connect screens showing frequencies from

CDM-VW300 ................................................................................. 47

7-17. RTDAQ screens showing frequencies in Public table ....................... 48

7-18. Dynamic Vibrating-Wire Tool Box Fault Indicators ......................... 49

A-1. Timing of dynamic vibrating-wire measurements .......................... A-2

B-1. Connection to the SC-CPI in DevConfig ......................................... B-2

C-1. CPI pin assignments ......................................................................... C-2

C-2. Long cable lengths of a distributed CPI bus ..................................... C-4

D-1. Geokon Calibration 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 measurement error on a 5000 foot Lead. Wire is

22 AWG with 16 ohms per 1000 feet. .......................................... F-4

Tables

5-1. CDM-VW300 / Datalogger Compatibility ........................................... 7

5-2. CDM-VW300/305 Sensor Resonant Frequency Range (Hz) ............... 8

5-3. CDM-VW300/305 Effective Frequency Measurement Resolution4 .... 8

6-1. CDM-VW300 Status LED States ....................................................... 15

6-2. DVWTool and CRBasic Settings ....................................................... 17

7-1. Summary of CDM-VW300 Configuration Settings ........................... 30

7-2. Relationship of Sample Rate and Sensor Frequency .......................... 34

7-3. Number of Analyzers and Channels Supported by a Datalogger

Writing to CF Card ......................................................................... 42

7-4. CDM-VW300 Scan Rate / Datalogger Scan() Interval Pairings ........ 44

7-5. CDM-VW300 Channel-Status LED States ........................................ 46

8-1. Scan Rate and Boundary Resolution .................................................. 53

8-2. Diagnostic Code Ranges .................................................................... 55

C-1. Maximum Potential Speed as a Function of Distance1 ..................... C-2

1

CDM-VW300 Series Dynamic Vibrating­Wire Analyzers

Configuring a dynamic vibrating-wire measurement system requires an integrated
system-wide approach. Please review this manual before connecting hardware
together or to the PC. The ResourceDVD, which ships free of charge with most
Campbell Scientific instrumentation orders, contains the following tools that will
help you configure a dynamic vibrating-wire analyzer system:

 A copy of this manual
 DVWTool Dynamic Vibrating-Wire Toolbox software for CDM-VW300

support

 DevConfig Device Configuration Utility software
 Required datalogger operating systems

Other support information and downloads are available at

www.campbellsci.com/cdm-vw300-support.

1. Introduction

Vibrating-wire sensors are commonly used in geotechnical or structural
monitoring applications to measure strain, load, tilt, inclination, temperature,
pressure, extension, and crack movement. CDM-VW300 Series 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

o Manual operation
o Does not require a datalogger
o Requires a PC
o Used in short-term evaluation
o Real-time data and metadata are monitored with PC

 Field mode

o Automated operation
o Requires a datalogger
o PC used only for setup and collection of data from datalogger
o Used in long-term monitoring applications
o Time-series data and metadata stored in datalogger memory

Two analyzer models are available in the CDM-VW300 series:

 CDM-VW300 (two channels)
 CDM-VW305 (eight channels)

See Table 5-1, CDM / Datalogger Compatibility, in Section 5, Specifications, for
datalogger compatibility information.

Other than a few clearly noted exceptions, any discussion in this manual of the
CDM-VW300 also applies to the CDM-VW305.

CDM-VW300 Series Dynamic Vibrating-Wire Analyzers

2

Before using the CDM-VW300, please study

 Section 2, Cautionary Statements
 Section 3, Initial Inspection

Detailed installation, operation, and troubleshooting information can be found in
the remaining sections.

2. Cautionary Statements

 CAUTION — Do not connect power to the system until it is completely

assembled.

 IMPORTANT — Do not connect the CDM-VW300 analyzer or SC-CPI

interface to a PC until AFTER installing DVWTool or DevConfig on the PC.
Consult Section 7.1.1, Software and Driver Installation, for more
information.

 All references to DVWTool mean Dynamic Vibrating-Wire Tool Box software

version 1.0 or later. DVWTool is available on current versions of the
ResourceDVD that ships with CDM-VW300 series analyzers. All references
to DevConfig mean Device Configuration Utility software version 2.04 or
later. DevConfig is available from the these three sources:

o ResourceDVD shipped with CDM-VW300 series analyzers
o www.campbellsci.com/downloads (no charge)
o Installations of LoggerNet, PC400, PC200W, or RTDAQ

software. Check the Help | About screen in DevConfig 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 model and part numbers, and product descriptions against the
shipping documents. Model or part numbers are found on each product.
Cable numbers are normally found at the end of the cable that connects to the
measurement device. Check that expected cable lengths were received.
Contact Campbell Scientific immediately concerning any discrepancies.

4. Overview

Single-coil vibrating-wire sensors are preferred in many applications because they
are stabile, accurate, and durable. CDM-VW300 Series Dynamic Vibrating-Wire
Analyzers make accurate high-speed measurements of the resonant frequencies of
these sensors at sub-second intervals using advanced excitation and signal
processing techniques, including spectral analysis. Resonant frequency data are
passed with diagnostics to a Campbell Scientific datalogger. Applications include
characterization of events that require rapid measurements and data storage, and

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.

CDM-VW300 Series Dynamic Vibrating-Wire Analyzers

4

Figure 4-3. Measurement speeds of the AVW200 and CDM-VW300

analyzers

4.3 Integrated Thermistor Measurement

Many vibrating-wire sensors include an integrated thermistor to allow for
temperature compensation of the vibrating-wire measurement. The CDM-VW300
supports thermistor measurements and the associated temperature compensation
required in some applications.

Figure 4-4. Single-coil vibrating-wire sensor including coil and thermistor

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-VW300 to
measure sensors. Specific procedures can be found in Section 6.1.2, Laboratory-
Mode Installation Procedure.

Vibrating Wire

Thermistor

Stainless Steel Housing

4-Conductor Cable

Filter

Plucking and Pickup Coils

Diaphragm

Internal Bulkhead Seal

Two Coil Outputs

Two Thermistor

Outputs

User Manual

5

Figure 4-5. Laboratory-mode measurement system diagram

4.5 Field Mode

Field mode is used for long-term measurement and data acquisition. As shown in
Figure 4-6, a connection is made from the CDM-VW300 to a Campbell Scientific
datalogger through the SC-CPI interface. A Campbell Scientific datalogger with a
customized CRBasic program configures, controls, and collects data from the
CDM-VW300. Specific installation procedures are found in Section 6.2.2, Field-
Mode Installation Procedure.

Figure 4-6. Field-mode data-acquisition system diagram

4.6 Data Uses

Users should consult authoritative sources concerning the use of vibrating-wire
data in structural 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 detecting the rare case, for example, in which a noise frequency very
near the resonant frequency affects dynamic sampling measurements.

4.6.2 Dynamic Measurements

Each analyzer can be configured in a 20, 50, 100, 200, or 333.3 Hz sampling
mode. By capturing multiple readings each second from a vibrating-wire sensor,
rapid changes or events can be captured and evaluated. Due to the Nyquist
sampling theorem, only responses equal to or less than half of the sampling

CDM-VW300 Series Dynamic Vibrating-Wire Analyzers

6

frequency can be detected and characterized. Event-based data capture techniques
programmed into the controlling datalogger can be helpful to ensure useful data
are captured under the right event conditions. In this way, storage and retrieval of
less-useful data are avoided.

4.6.3 Thermistor Measurements

Each vibrating-wire sensor input channel has inputs for the thermistor that is
usually built into a vibrating-wire sensor. The temperature measurement is
normally used to correct the frequency measurement for temperature changes. A
24-bit measurement circuit ensures high-accuracy resistance measurements, which
are converted to temperature. Guidance about the impact of temperature on the
vibrating wire is usually provided by the manufacturer in documentation provided
with each individual sensor. Contact the sensor manufacturer if more information
is required.

4.6.4 Rainflow Histograms

Rainflow histograms are 3-D representations of the rainflow counting algorithm of
Matsuiski and Endo (1968). Rainflow histograms can be used to monitor fatigue
levels of structures under stress, such as components of a large-scale
transportation 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
are provided for each dynamic measurement. A standard deviation is provided
once each second.

Excitation level is bounded by setting the amplitude at which the wire in the
sensor is to be maintained. That figure is reported so that excitation levels can be
monitored. If the analyzer-sensor system experiences a low amplitude, high
amplitude, low-frequency, or high frequency condition, that information is also
provided.

Once each second, a standard deviation of a dynamic measurement is provided.
Unexplained changes in the standard deviation from baseline levels may indicate
noise or other interference.

5. Specifications

5.1 Features

 Measurement of standard, single-coil circuit, vibrating-wire sensors
 Dynamic-sampling rates of 20 to 333.3 Hz
 On-board frequency-output conversion
 Two (CDM-VW300) or eight (CDM-VW305), simultaneously-sampled

channels per module

 Time synchronization of multiple modules using one datalogger
 Thermistor input for each vibrating-wire channel measured at 1 Hz

User Manual

7

 On-board temperature conversion
 Rainflow-histogram compilation
 Superior noise immunity and effective measurement resolution (precision)
 Continuous resonant vibration in the sensor
 Spectral analysis method protected under U.S. patent no. 7,779,690. An

additional U.S. patent that relates to the dynamic vibrating-wire measurement
technique is pending.

5.2 Specifications

Electrical specifications are valid from –25 to 50 °C unless otherwise specified.
Non-condensing environment required. Specifications are subject to change.

Compatibility:

Table 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. The wire is maintained in a
continuously vibrating state. Excitation
voltage varies automatically to maintain
the desired return signal strength.

Dynamic measurement
rates:

20, 50, 100, 2003, and 333.33 Hz

Accuracy:

±(0.005% of reading + effective
measurement resolution)

Input resistance:

5 kΩ

Excitation voltage

Range:

0 to ±3 V (6 V peak-to-peak)

Resolution:

26 mV

CDM-VW300 Series Dynamic Vibrating-Wire Analyzers

8

Sensor resonant frequency

range:

Table 5-2. CDM-VW300/305

Sensor Resonant Frequency Range (Hz)

Sample Rate

Minimum Sensor

Frequency

Maximum Sensor

Frequency

20

290

6000

50

290

6000

100

580

6000

2003

1150

6000

333.33

2300

6000

Effective resolution (precision):

Table 5-3. CDM-VW300/305

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 CDM­VW305 analyzers.

Accuracy:

0.15% of reading6

Resolution:

0.002 Ω RMS @ 5 kΩ thermistor

resistance

Bridge resistor:

4.99 kΩ 0.1%

Excitation voltage:

1.5 V

Measurement rate:

1 Hz

User Manual

9

Operating temperature

Standard:

–25° to 50°C

Extended:

–55° to 85°C

Power requirement

Voltage:

9.6 to 32 Vdc

Typical current drain

CDM-VW300:

115 mA @ 12 Vdc

CDM-VW305:

190 mA @ 12 Vdc

Output

CPI:

Connects to datalogger. Baud rate
selectable from 50 kbps to 1 Mbps.
Cable length varies depending on
baud rate, number of nodes, cable
quality, and noise environment.
2500 ft maximum.

USB:

Connects to PC. USB 2.0 full speed.
Provided for configuration, updates,
and communication with DVWTool
software. The USB port does not
support collection of time-series
data.

Weight:

< 1 kg, < 2 lb

Dimensions:

20.3 x 12.7 x 5.1 cm (8 x 5 x 2 in)

Mounting:

One-inch grid. Optional DIN rail
mounting is available using
Campbell Scientific pn #29388.

1

SC-CPI module connects to terminals C1, C2, C3 (not SDM-C1, SDM-C2, SDM-C3).

2

CR3000 is the recommended datalogger.

3

These rates 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 field data­acquisition system using a Campbell Scientific CR3000 datalogger. When sensors
are sampled at slower rates equal to or less than 50 Hz, a CR1000 or CR800
datalogger can be used.

Pre-configure and test the system before taking it to the field. Issues that are
unresolved before placing instrumentation in the field will usually be more
difficult to resolve. Data-acquisition systems, from the sensors to the
telecommunications equipment, are complex. Campbell Scientific equipment and
software are among the best available, but the integration process can be
demanding and involves trial and error; contingencies should be developed to

CDM-VW300 Series Dynamic Vibrating-Wire Analyzers

10

address possible problems. Do the bulk of the integration work in a comfortable
and dry location that has a communications link with Campbell Scientific during
regular business hours. If you are experienced with field deployments, set aside at
least a full day for pre-configuration work. Otherwise, set aside three to seven
days for system development before travelling to the field.

6.1 Laboratory-Mode Installation

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 Installation, for more information.

Laboratory mode allows for easy examination and validation of measurements.
To ensure a successful field deployment, perform 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 measurement system

6.1.1 Laboratory-Mode Installation Equipment

The following equipment is used in a laboratory-mode installation:

 Vibrating-wire sensors
 CDM-VW300 measurement module
 PC
 DVWTool software

6.1.2 Laboratory-Mode Installation Procedure

The following procedure sets up the measurement system in laboratory mode:

1. Install DVWTool software on the PC. Do this before connecting the CDM-

VW300 to the PC. DVWTool installation automatically installs drivers for the
CDM-VW300 USB connection.

Reference Section 7.1.1, Software and Driver Installation.

2. Connect 12 Vdc power to the CDM-VW300 as shown in Figure 6-2.

User Manual

11

Reference Section 7.4, Using Power Supplies.

Campbell Scientific pn #29796, a 24 Vdc, 1670 mA wall charger, is
recommended.

Figure 6-2. 12 Vdc power connection on the CDM-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.

CDM-VW300 Series Dynamic Vibrating-Wire Analyzers

12

With the driver installed (step 1) and the power connected and live (step 2),

connecting the USB cable will start an automatic process that creates a new
communication (COM) port for the CDM-VW300 on the PC. Watch the
Windows® system tray to see that the PC completes the process. Once
complete, a new port will appear as an available communication port in
DVWTool.

4. Test to see 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 the lower left of the DVWTool window. If DVWTool

connects with the CDM-VW300, the channel list on the DVWTool interface
becomes available and the button at lower left reads Disconnect as shown in
the following figure.

NOTE

User Manual

13

Notice that the fields Device Type, Serial Number, Device Name, and CPI
address are active and populated in the lower portion of the DVWTool
window. Otherwise, the channel list remains dimmed and the notice Not
connected... No data available is displayed 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 DVWTool Help | About screen, which is sampled in the
following figure.

CDM-VW300 Series Dynamic Vibrating-Wire Analyzers

14

6. If DVWTool 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

User Manual

15

Figure 6-5. Three-wire vibrating-wire sensor connections

Figure 6-6. Five-wire vibrating-wire sensor connections

8. Reconnect 12 Vdc power to the CDM-VW300.

9. Confirm sensor operation.

Reference Section 7.12.1, Sensor Validation.

Two status LED lights are provided on the CDM-VW300 for each sensor
connection. Eight are provided on the CDM-VW305. The following table
lists LED functions and interpretations:

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 the DVWTool window. Check the box associated with
each channel to which a sensor is connected. If all sensor systems are
operational, the DVWTool main window will appear much as it does in the
following figure:

CDM-VW300 Series Dynamic Vibrating-Wire Analyzers

16

a. Frequency reading of each sensor will correspond to the frequency

range specified by the sensor manufacturer.

b. No faults are indicated. If faults are indicated (Diagnostic Bits does

not equal 0x00, measurement results are in red type, or cells are
shaded red), consult Section 7.12.2.1, Monitoring with DVWTool
Software, for troubleshooting help.

6.2 Field-Mode Installation

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 Installation, for more information.

A simple field-mode configuration, using one CDM-VW300, is covered in this
section. Additional details concerning field-mode configuration and daisy­chaining 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 components are used in a field-mode installation:

 Vibrating-wire sensors
 CDM-VW300 measurement modules
 SC-CPI interface
 Datalogger
 Datalogger power supply
 Personal computer (PC)
 DVWTool analyzer software
 Datalogger support software (LoggerNet, PC400, or RTDAQ)

6.2.2 Field-Mode Installation Procedure

Figure 6-7 illustrates the final form of a simplified field-mode installation. With
reference to this figure, work through the following procedure. Reference Section

7.7, System Connections, for more information.

User Manual

17

Figure 6-7. Field data-acquisition system

Procedure:

1. Install DVWTool before connecting the SC-CPI or CDM-VW300 to the PC.

Reference Section 7.1.1, Software and Driver Installation.

2. Before proceeding, follow the procedure outlined in Section 6.1, Laboratory-

Mode Installation for all sensors connected to the CDM-VW300. Record
settings determined in DVWTool for later use in the CRBasic program. The
following work sheet (Table 6-2) lists DVWTool settings and corresponding
CRBasic instruction 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

Interval

1

No corresponding setting

Units = msec

No corresponding setting

Buffer = 500

No corresponding setting

Count = 0

CDM_VW300Config()

Device Type (auto-detected)

DeviceType

CPI Address

CPIAddress

No corresponding setting

SysOptions

Channel X Enable check box

ChanEnable

Resonant Amplitude (V)

ResonAmp

Minimum Frequency (Hz)

LowFreq

Maximum Frequency (Hz)

HighFreq

Output Format (Hz or Hz2)

ChanOptions

CDM-VW300 Series Dynamic Vibrating-Wire Analyzers

18

Multiplier

Mult

Offset

Offset

Steinhart-Hart Thermistor
Coeff A

SteinA

Steinhart-Hart Thermistor
Coeff B

SteinB

Steinhart-Hart Thermistor
Coeff C

SteinC

Rainflow | Number of Mean
Bins

RF_MeanBins

Rainflow | Number of Amp
Bins

RF_AmpBins

Rainflow | Low Limit

RF_LowLim

Rainflow | High Limit

RF_HighLim

Rainflow | Minimum Change

RF_Hyst

RF_Form

Rainflow | Rainflow Form |
reset list

A

Rainflow | Rainflow Form |

total list

B

Rainflow | Rainflow Form |

form list

C

1

Scan rate is automatically set based on the datalogger CRBasic Scan() instruction
Interval parameter. Set the Interval parameter such that the desired CDM-VW300
scan rate is achieved. Relationship between Scan Rate and Interval is:

CRBasic 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-acquisition system requires a reliable power supply. CDM-

VW300 analyzers consume more power than do many Campbell Scientific
products, so the power supplies often used with other data-acquisition
systems may not be adequate. Consult Section 7.4, Using Power Supplies, for
sizing guidance. For large systems, consult with a Campbell Scientific
application engineer.

6. The following figure illustrates the connections between the datalogger, SC-

CPI interface, and CDM-VW300. With this figure as a reference, work
through the following procedure.

User Manual

19

Figure 6-8. CPI communications links

a. Connect the SC-CPI to the datalogger. Reference Figure 6-9, Datalogger

to SC-CPI Connection.

CR3000, CR1000, and CR800 dataloggers require that a SC-CPI
interface the datalogger to the CDM-VW300. Connect 12V, G, C1, C2,
and C3 from the SC-CPI to the corresponding 12V, G, C1, C2 , and C3
ports of the datalogger.

SC-CPI module connects to terminals C1, C2, C3 (not SDM-C1,
SDM-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 for CPI bus communications
from cables used for Ethernet communications.

NOTE

SC-CPI to Datalogger

12V to 12V

G to G
C1 to C1
C2 to C2
C3 to C3

SC-CPI to CDM-VW300

CPI to CPI

(RJ-45 to RJ-45)

CPI Bus

Terminator

CDM-VW300 Series Dynamic Vibrating-Wire Analyzers

20

Figure 6-10. Connecting the CPI ports of the SC-CPI and CDM-VW300

c. As shown in Figure 6-11, place a CPI terminator in the remaining open

CPI port of the CDM-VW300 unless more CDM-VW300 devices will be
daisy-chained.

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 face of the datalogger.

Connect SC-CPI to CDM-VW300:

RJ-45 to RJ-45

User Manual

21

Figure 6-12. Power connection

8. As shown in Figure 6-13, connect earth grounds.

Ground lugs are provided for tying 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.

CDM-VW300 Series Dynamic Vibrating-Wire Analyzers

22

CDM-VW300 and CDM-VW305 programs use the following CRBasic
instructions:

CDM_VW300Config()

CDM_VW300Dynamic()
CDM_VW300Static()

The CRBasic program must be enabled specifically for the CDM-VW300 or
the CDM-VW305. Programs enabled for a CDM-VW300 use a DeviceType
argument of 0 in the CDM_VW300Config() instruction. Programs enabled
for a CDM-VW305 use a DeviceType of 1. Check that other settings
recorded in step 2 are integrated into the CRBasic program.

Do not attempt to use a program written 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 programs can be used. These programs measure only basic
frequency:

 Appendix G.1.1, 20 Hz Measurement Example – One CDM-VW300,

Two Channels

 Appendix G.1.2, 20 Hz Measurement Example – One CDM-VW305,

Eight Channels

10. Send the CRBasic program to the datalogger using the program Send

command in the datalogger support software (RTDAQ, LoggerNet, or
PC400).

NOTE

User Manual

23

11. Monitor the operation of the system.

Reference Section 7.12.2, Monitoring System Performance.

Using the datalogger support software, monitor the datalogger Public table as
indicated in the following figure. In the Public table, frequency data can be
displayed that correspond to the channels selected for measurement. The
following figure shows Public table variables Freq(1), Diag(1),
StaticFreq(1), Therm(1), DynStdDev(1) as active with frequency data from
one sensor. The sensor is connected to channel 1 of the CDM-VW305.

A clean display of data, as shown in the previous figure, is obtained by
deactivating all but channel 1 in the CRBasic program. If channels 2 through 8
had not been deactivated, erroneous, but perhaps seemingly-real, data would be
displayed. Channels 2 through 8 are deactivated by setting line 24 in the CRBasic
example in Appendix G.1.2, 20 Hz Measurement Example – 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 AFTER installing DVWTool 1.0 or later or DevConfig 2.04 or later.
Consult Section 7.1.1, Software and Driver Installation, for more information.

7.1 PC Based Tools

All PC software is for use on Windows® XP, Windows® Vista, Windows® 7, or
Windows® 8 operating systems.

7.1.1 Software and Driver Installation

USB communication between the PC and the CDM-VW300 analyzer, and
between the PC and the SC-CPI interface, require that USB drivers be installed on
the PC. For driver installation to work seamlessly, the drivers must be installed
before making the physical USB connections. These drivers are installed
automatically when DVWTool 1.0 software or DevConfig 2.04 software or later
are installed.

CDM-VW300 Series Dynamic Vibrating-Wire Analyzers

24

 If the physical USB connection is attempted before the installation of the

drivers, a non-functional placeholder definition is created in the
Windows® USB device list. This placeholder prevents that device from
becoming active during subsequent driver installs and device connections
via USB. The following procedure should correct this condition:

1. Install either DVWTool 1.0 or later or DevConfig 2.04 or later.

2. Connect the device to the computer with the USB cable.

3. Open the Windows® Device Manager. In Windows® 7, this is

done by choosing Control Panel | Hardware and Sound, and
then clicking on the Device Manager icon found in the Devices
and Printers section.

4. 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 Scan for

hardware changes or Update Driver Software....

5. The driver will be found and the disabled placeholder will be

overridden.

 If USB drivers are installed on Windows® 8:

The installation of the USB drivers can fail silently on the Windows® 8
platform under certain circumstances. This problem is indicated by the
absence of the CDM-VW300 COM port from the list 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

The Dynamic Vibrating-Wire Tool Box (DVWTool) is a software package that
enables a PC to communicate with the CDM-VW300 via USB, configure CDM­VW300 settings, and display the output of attached sensors. No datalogger is
required. Data are output in the main window table, on a line graph, and in a
rainflow histogram.

Users of the CDM-VW300 should become familiar with the function and
operation of DVWTool. Detailed information about this software can be found in
the DVWTool Help system.

7.1.2.1 Ensure Connection is Active

The installation of DevConfig 2.04 or later or DVWTool 1.0 or later automatically
installs the drivers required to make a connection between the CDM-VW300 and
the PC. Do not connect a USB cable between your CDM-VW300 and the PC
until after DevConfig or DVWTool has been installed. Before starting DVWTool ,
ensure that the CDM-VW300 analyzer is connected to the PC via USB cable.
After opening DVWTool, choose the CDM-VW300 port from the Com Port
dropdown list, as indicated in Figure 7-1. Click the Connect button.

User Manual

25

Figure 7-1. DVWTool Settings Editor and Data Display

If CDM-VW300 does not appear in the available selections for
Com Port, 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.

7.1.2.2 DVWTool Settings Editor

See Table 7-1, Summary of CDM-VW300 Configuration Settings, for a listing of
settings that can be viewed and edited with DVWTool.

7.1.2.3 Button and Field Descriptions

Enable — select each checkbox to turn on the respective channel.

Dynamic Frequency is the resonant frequency of the vibrating-wire sensor

sampled at the specified scan rate. This is the primary output of the attached
analyzer. If the Output Format field is set to Freq 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 for the slower rate at which it is computed.

Static Thermistor (ohms) is a measure of the resistance across the thermistor
inputs. It is measured once per second. If the Steinhart-Hart Thermistor
Coefficients (A, B, and C) are entered for the channel, then they are used to

convert the measured resistance to degrees Celsius.

Standard Deviation of Dynamic Frequency (Hz or Hz2) is the standard
deviation of the Dynamic Frequency field computed on one-second data. It is
output once per second. It is computed after the Output Format, Multiplier, and
Offset have been applied.

NOTE

CDM-VW300 Series Dynamic Vibrating-Wire Analyzers

26

Resonant Amplitude (V) sets the desired amplitude of the steady-state signal
response from the sensor.

Excitation Strength (V) is the peak-to-peak amplitude of the excitation waveform
that is required to produce the desired response amplitude. An increase in the

Scan Rate corresponds to a decrease in the excitation strength needed.

Diagnostic Bits provides information on the operation of the module and can

indicate conditions during which the data may be suspect.

The Minimum Frequency (Hz) and Maximum Frequency (Hz) are the bounds
in which the resonant frequency of the sensor is expected to fall during its
operation. Signal frequencies measured outside of this range are not included in
the spectral analysis, except as noted in Section 8.5.1.1, Description of Diagnostic
Parameters.

Graph button brings up a graphical display of the frequency output of the sensors.

Pressing the Rainflow button and selecting a channel brings up a rainflow
histogram of the 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 of the CDM-VW300 should become familiar with the function and
operation of DevConfig. Detailed information about this software can be found in
the DevConfig Help system and the LoggerNet software manual, which is
available at www.campbellsci.com.

7.1.3.1 Ensure Connection is Active

The installation of DevConfig 2.04 or later or DVWTool 1.0 or later automatically
installs the drivers required to make a connection between the CDM-VW300 and
the PC. Do not connect a USB cable between your CDM-VW300 and the PC
until after DevConfig or DVWTool has been installed. Before starting DevConfig,
ensure that the CDM-VW300 analyzer is connected to the PC via USB cable.
After opening DevConfig, choose the CDM-VW300 port from the

Communication Port dropdown list as indicated in Figure 7-2. Click the
Connect button.

User Manual

27

Figure 7-2. DevConfig Settings Editor

Details about using DevConfig can be found in DevConfig Help or in the
LoggerNet datalogger support software manual, which is available at

www.campbellsci.com.

If a COM port CDM-VW300 does not appear in the available
selections for Communications Port, then 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.

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 outputs is loaded into the datalogger.

Write or obtain a CRBasic program for the datalogger. Reference Section 7.10,

CRBasic Programming. Example programs are available in Appendix G,
CRBasic Program Library, and at www.campbellsci.com/cdm-vw300-support.

NOTE

CDM-VW300 Series Dynamic Vibrating-Wire Analyzers

28

7.3 Using the SC-CPI Interface

See Appendix B, SC-CPI Datalogger to CPI Interface.

7.4 Using Power Supplies

See Section 7.7.4, CDM-VW300 to Power Connection, for instructions and
precautions when connecting power.

7.4.1 CDM-VW300 Series Analyzer Power

The purchase of a CDM-VW300 series analyzer does not include a power supply.
A 12 Vdc power source must be specifically ordered or provided by other means.
Power supplies providing 9.6 to 32 Vdc, with a 200 mA or greater current rating,
can be used. Transformer pn #29796, which is illustrated in Figure 7-3, is a 24
Vdc, 1.67 A wall charger. It can be purchased from Campbell 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 a battery base (Campbell Scientific pn #9591), does
not have the correct power output for the CDM-VW300.

7.4.2 Data-Acquisition System Power

Power supply requirements will vary depending on system configuration and
location. The following power supplies are typically adequate to power a data­acquisition system consisting of one datalogger, one CDM-VW300, and the SC­CPI interface:

 PS100 connected to ac
 PS200 connected to ac
 CR3000 rechargeable base connected to ac

NOTE

User Manual

29

CR3000 with alkaline base is NOT an adequate power supply and
will fail shortly after deployment.

A solar powered system requires careful planning including a power budget. For
example, to power a data-acquisition system consisting of a CR3000 datalogger,
an SC-CPI interface, and a CDM-VW300 series analyzer, the following battery
and solar panel specifications are required to operate the system year-round in a
remote installation in northern Utah using standard silicon cell solar panels, lead­acid rechargeable batteries, and industry accepted reserve margins:

 CDM-VW300, two channels enabled

o 60 watts of solar panel capacity
o 91 ampere-hours of battery reserve

 CDM-VW305, eight channels enabled

o 84 watts of solar panel capacity
o 130 ampere-hours of battery reserve.

Many applications will require the use of several analyzers. A carefully
considered power budget in these applications is essential to ensuring system
reliability 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 more information about the software. See Section 7.10, CRBasic
Programming, for more information about using the datalogger.

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 Installation, for more information.

If using software to configure the analyzer, which is recommended, physically
connect the CDM-VW300 to the PC with a USB cable. See Section 7.7.1, CDM-
VW300 to PC Connection, for assistance in making this connection. Check that
the software is pointing to the correct communications port.

Table 7-1, summarizes the configuration settings. Each configuration setting is
discussed in the following sections.

NOTE

CDM-VW300 Series Dynamic Vibrating-Wire Analyzers

30

Table 7-1. Summary of CDM-VW300 Configuration Settings

Setting Description

DVWTool PC Software

Setting Name

DevConfig PC Software

Setting Name

CRBasic Datalogger

Instructions /

Parameters

Device name

Device Name

Device Name

ncs

CPI bus speed (kbps)

CPI Bit Rate

CPI Bit Rate

CPISpeed()

Operating system
version

ncs1

OS Version

ncs
Operating system date

ncs

OS Date

ncs

Analyzer serial
number

Serial Number

Board Serial Number

ncs

Display rate

DVWTool Decimation

DevConfig 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 Amplitude (V)

RMS Amplitude Set
Point

CDM_VW300Config()

ResonAmp

Minimum cut-off
frequency

Minimum Frequency (Hz)

Low Freq. bound

CDM_VW300Config()

LowFreq

Maximum cut-off
frequency

Maximum Frequency (Hz)

High Freq. bound

CDM_VW300Config()

HighFreq

Frequency-output
format

Output Format (Hz or
Hz2)

Output Format

CDM_VW300Config()

ChanOptions

User Manual

31

Setting Description

DVWTool PC Software

Setting Name

DevConfig PC Software

Setting Name

CRBasic Datalogger

Instructions /

Parameters

Multiplier

Multiplier

Multiplier

CDM_VW300Config()

Mult

Offset

Offset

Offset

CDM_VW300Config()

Offset

Steinhart-Hart
coefficients

Steinhart-Hart
Thermistor Coeff A

Thermistor A

CDM_VW300Config()

SteinA

Steinhart-Hart
Thermistor Coeff B

Thermistor B

CDM_VW300Config()

SteinB

Steinhart-Hart
Thermistor Coeff C

Thermistor C

CDM_VW300Config()

SteinC

Rainflow-histogram
output configuration

Rainflow | Number of
Mean Bins

Rainflow Mean Bins

CDM_VW300Config()

RF_MeanBins

Rainflow | Number of
Amp Bins

Rainflow Amp Bins

CDM_VW300Config()

RF_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 the CRBasic datalogger instruction setup.

7.5.2 CPI Bus Speed

This setting specifies the speed at which the CDM-VW300 communicates with the
CPI bus. Speed options are 50, 125, 250, 500, and 1000 kbps. In a CRBasic
program, use the CPISpeed() instruction to set this setting. Shorter CPI cable
lengths allow for a faster CPI bus speed.

7.5.3 Operating System Version

This field reports the version of the CDM-VW300 operating system. This setting
is viewable only in DevConfig.

CDM-VW300 Series Dynamic Vibrating-Wire Analyzers

32

7.5.4 Operating System Date

This field reports the release date of the CDM-VW300 operating system. This
setting is viewable only in DevConfig.

7.5.5 Analyzer Serial Number

This field reports the serial number of the CDM-VW300. The same serial number
is on a tag on CDM-VW300 case. This setting is viewable DVWTool and
DevConfig.

7.5.6 Display Rate

This setting specifies the rate at which PC displays are updated. This is not an
option in the CRBasic datalogger instruction setup.

7.5.7 Dynamic Sample Rate

This setting is entered in units of Hz (hertz) in DVWTool and DevConfig. Options
are 20, 50, 100, 200, or 333.3 kHz. This is set for lab mode using DVWTool. In
field mode, it is determined automatically from the Interval argument CRBasic
program Scan() instruction. It is calculated for the Interval parameter as:

Interval = (1 / DVWTool Scan Rate • 1000).

7.5.8 Device Type

This setting specifies whether the analyzer is a CDM-VW300 (Option 0) or CDM­VW305 (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 Interface. Addresses range from
1 to 120.

7.5.10 System Options

This setting determines if a numeric value or NAN will be stored in the datalogger
when a flag condition occurs, and whether or not the diagnostic LEDs are on or
off. This option is available for only the CRBasic datalogger program. Options
are 0, 1, 10, and 11.

7.5.11 Channels Enabled

Each channel on a CDM-VW300 series analyzer can be individually enabled for
measurement. If a channel is not enabled, the LED corresponding to it will not
flash. If the channel is enabled, but there is a diagnostic warning, the LED will
flash red. If the device is enabled and obtaining a reading properly from the
attached sensor, the LED will flash green. Channels are enabled either with check
boxes or Boolean values.

User Manual

33

7.5.12 Desired Resonant Amplitude

This is the target amplitude, measured in volts, for keeping the wire of the sensor
in constant excitation. The excitation voltage is adjusted automatically by the
analyzer to accommodate the target resonant amplitude. This is set to a minimum
of 100 µV and a maximum of 10 mV. Default is 2 mV.

7.5.13 Minimum- and Maximum Cut-Off Frequencies

Band-pass filters can be set to isolate a certain frequency range within which a
reading is expected to fall. See Section 7.11.1, Frequency Range, for more
information. Settings are frequency values.

7.5.14 Frequency-Output Format

Use this setting to select whether the output from the sensor will be given as
frequency (Hz) or frequency squared (Hz2). Settings are selected from lists in the
PC software. Entry in CRBasic is Boolean (0 = Hz, 1 = Hz2).

7.5.15 Multipliers and Offsets

Multipliers (gain, slope, or scaling) and offsets (y-intercept or shifting) allow for
linear scaling of the frequency output of each sensor. Some vibrating-wire sensors,
however, require polynomial calculations to obtain the desired engineering units.
If transformation other than linear scaling is required, the multiplier should be set
to 1 and the offset to 0, and the transformation made 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.

7.5.16 Steinhart-Hart Coefficients

These coefficients are used to convert thermistor resistance from ohms to
temperature in degrees Celsius. See Appendix F, Thermistor Information, for
more information.

7.5.17 Rainflow-Histogram Output Configurations

Output configuration settings in DevConfig and CRBasic are three digit values.
For example, an entry of 100 means reset histogram, divide bins by total count,
and use open form.

Options:

 0 = reset histogram each output / 1 = Do not reset histogram.
 0 = Divide bins by total count / 1 = use the total of each bin.
 0 = Open form (includes half cycles) / 1 = Closed form (use full cycles)

Settings in DVWTool are selected from lists.

7.6 Sensor Selection

CDM-VW300 series analyzers work well with standard vibrating-wire sensors
that use a single-coil circuit design. In this design, two sensor leads are used to
both excite the sensor and read back the resonant frequency. When selecting a
vibrating-wire sensor, consider its frequency range and the sample rate at which
that frequency will be sampled by the datalogger or PC.

CDM-VW300 Series Dynamic Vibrating-Wire Analyzers

34

7.6.1 Frequency Considerations

In general, sensors with higher resonant-frequency ranges are more versatile when
used with a CDM-VW300 series analyzer. Higher sample rates require a higher­frequency range on the sensor.

Based on the dynamic rate used to sample the sensor, be aware of the low-end
(minimum) frequency limitations of the CDM-VW300 as given in the following
table:

Table 7-2. Relationship of Sample Rate and Sensor Frequency

Sample

Rate (Hz)

Min Sensor

Freq (Hz)

Max Sensor

Freq (Hz)

20

290

6000

50

290

6000

100

580

6000

200

1150

6000

333.3

2300

6000

Be sure that the expected frequency response of the sensor does not fall outside
the specified limits even when responding to maximum or minimum 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 Installation, for more information.

7.7.1 CDM-VW300 to PC Connection

A PC to CDM-VW300 USB connection is used in a laboratory-mode installation
and in the initial setup and troubleshooting of field-mode installations.

Connect a male-USB to type-micro-B male-USB cable between the PC and the
CDM-VW300 analyzer; pn #27555, provided in the CDM network kit (pn
#29370), which is shipped with each analyzer, can be used. The type-micro-B
male-USB connector connects to the CDM-VW300. The USB port is located on
the analyzer as shown in Figure 7-4, USB port on the CDM-VW300.

User Manual

35

Figure 7-4. USB port on the CDM-VW300

When the connection is made, DVWTool or DevConfig can be used to
communicate with and configure the analyzer. DVWTool is the preferred software
tool.

7.7.2 CDM-VW300 to Sensor Connection

Typical single-coil vibrating-wire sensors come with either three- or five-wire
connection leads. Refer to the 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 polarity position of the two signal wires. Two coil
connections (C) are provided on each channel on the CDM-VW300 to which these
leads are connected.

CDM-VW300 Series Dynamic Vibrating-Wire Analyzers

36

Figure 7-6. Three-wire vibrating-wire sensor connection

The third lead is the shield wire, or sensor ground, and should be connected 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.

User Manual

37

Figure 7-8. Five-wire vibrating-wire sensor connection

Since temperature is a factor that can influence the frequency output of a
vibrating-wire sensor, a temperature measurement is often part of the calculation
used to convert the frequency output of the sensor to 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) can be used to identify an RJ45 cable that is being used for CPI bus
communications.

CDM-VW300 Series Dynamic Vibrating-Wire Analyzers

38

Figure 7-9. SC-CPI and CDM-VW300 CPI ports with RJ45 cable marked

with yellow tape

Place a terminator in the remaining open CPI port 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

User Manual

39

Figure 7-11. Multiple analyzers on a CPI bus

7.7.4 CDM-VW300 to Power Connection

Connect 12 Vdc power to the Power In connector on the side of the CDM­VW300. 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

CDM-VW300 Series Dynamic Vibrating-Wire Analyzers

40

Figure 7-12. Installing 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.

User Manual

41

7.7.5 Earth Ground Connections

Earth grounding provides protection from static discharge, transients, and power
surges. Ground lugs are provided on the CDM-VW300 and the datalogger for
connection to earth ground with high-gauge wire. Minimum 14 AWG ground
wire is recommended. The earth side of the connection should be to a grounding
rod or other grounded device. Consult the datalogger manual for more
information on earth grounding.

Figure 7-14. Earth ground connections

7.7.6 Communication Connections

A CDM-VW300 analyzer can connect to both PC software via USB (DVWTool or
DevConfig) and the datalogger (through the SC-CPI, via RJ-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 not be executed at the hardware level, so it will have no impact on the
operation of the device.

7.7.6.1 SC-CPI to CPI Bus Connection

See Appendix B, SC-CPI Datalogger to CPI Interface.

7.7.6.2 Datalogger to SC-CPI Connection

CR3000, CR1000, and CR800 dataloggers require a SC-CPI interface to connect
with the CDM-VW300. Connect 12V, G, C1,C2 and C3 from the SC-CPI to the
corresponding 12V, G, C1, C2, C3 ports of the datalogger, as shown in Figure
7-15.

CDM-VW300 Series Dynamic Vibrating-Wire Analyzers

42

Figure 7-15. CR3000 and SC-CPI connections

SC-CPI module connects to terminals C1, C2, C3 (not SDM-C1,
SDM-C2, SDM-C3).

7.7.7 Maximum Number of Analyzers on a Datalogger

The maximum number of active CDM-VW300 or CDM-VW305 analyzers and
channels that can be managed by a single datalogger is a function of the dynamic
sample or scan rate. The following table lists example configurations that have a
full complement of analyzers.

Table 7-3. Number of Analyzers and Channels Supported by a

Datalogger Writing to CF Card

Measurement

Rate

CR3000

Datalogger

CR1000

Datalogger

CR800

Datalogger

20 Hz

48 Channels on

6 CDM-VW305s

32 Channels on

4 CDM-VW305s

32 Channels on

4 CDM-VW305s

50 Hz

24 channels on

3 CDM-VW305s

8 channels on

1 CDM-VW305

8 channels 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 controlling eight CDM-VW305 analyzers with two active channels on
each analyzer making measurements at 20 Hz. The number of active channels is
16, but the system fails because the maximum number of analyzers (6) has been
exceeded, even though the maximum number of channels has not.

Two notes about CR1000 and CR800 dataloggers with a full analyzer
compliment:

 Final storage will significantly lag behind real time — several minutes in

some cases.

 These dataloggers get into a state wherein they measure and store so

intensely that little time remains to communicate with LoggerNet or RTDAQ
software.

NOTE

User Manual

43

The CR3000 datalogger is the only datalogger currently available (as of August

2013) that will allow near real-time monitoring of events.

7.8 Operating System

The following components of a dynamic vibrating-wire data-acquisition system
require an operating system (OS):

 CDM-VW300 series analyzer
 Datalogger
 SC-CPI interface

Operating systems may be updated on occasion to address new or enhanced
features, or bugs fixes. The frequency of updates decreases as a product matures.
If a product is received within six to twelve months of its first shipment, check the
operating system identifiers against those listed at

www.campbellsci.com/downloads upon receipt. The CDM-VW300 series

analyzers and SC-CPI interface were first shipped in April of 2013.

Updating an operating system usually clears all settings. Always
save the current settings of the device before loading an operating
system.

Use DevConfig to update the CDM-VW300 operating system. In the DevConfig
CDM-VW300 option, check the operating system version in the Settings Editor
tab. Download operating system updates in the Send OS tab by following the
instruction outlined therein.

7.9 Power-Up Sequence

Switch power to the CDM-VW300 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 light on the analyzers may flash both green and red
intermittently. When the SC-CPI is finished initializing the network, the CPI
Status and Serial Status LEDs will flash green, as will the COMM Status light
for each analyzer. If initialization fails, LEDs on all devices will flash red.

If the datalogger or SC-CPI interface loses power, and the CDM-VW300
analyzers do not, the COMM Status light on each device will change to red
indicating that the connection to the CPI network is lost. Usually, restoring power
to the datalogger (assuming it is still running a CDM-VW300 enabled program)
and SC-CPI will automatically reinitialize the network.

7.10 CRBasic Programming

7.10.1 Writing Programs

In field-mode installations, the system datalogger requires a user-entered CRBasic
program. Programs can be written either from scratch using CRBasic instructions
or copied from the example programs provided in Appendix G, CRBasic Program
Library. The following CRBasic instructions are used. For details concerning

NOTE

CDM-VW300 Series Dynamic Vibrating-Wire Analyzers

44

each instruction, consult CRBasic Editor Help. CRBasic Editor is included with
PC400, LoggerNet, and RTDAQ datalogger support software.

CDM_VW300Config() sends configuration settings to the CDM-VW300. It is
placed before the BeginProg statement in the CRBasic program. Before starting
the datalogger program, the datalogger configures the specified analyzer according
to the arguments in this instruction.

CDM_VW300Config() cannot be used to set the CPI address of the CDM­VW300. See Section 7.5.9, CPI Bus Address, for information on how to set the
CPI address.

CDM_VW300Config(DeviceType, CPIAddress, SysOptions, ChanEnable,

ResonAmp, LowFreq, HighFreq, ChanOptions, Mult, Offset, SteinA,
SteinB, SteinC, RF_MeanBins, RF_AmpBins, RF_LowLim, RF_HighLim,
RF_Hyst, RF_Form)

Scan() sets the scan interval to match the desired scan rate used for CDM-VW300
dynamic readings. For example:

Scan(50,msec,100,0)

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 dynamic readings from sensors. It is used in
the main scan of the CRBasic program.

CDM_VW300Dynamic(CPIAddress, DestFreq, DestDiag)

CDM_VW300Static() captures static readings such as thermistor, static
frequency, and standard deviation of dynamic frequencies at 1 Hz. It is used in
the main scan inside of a TimeIntoInterval() conditional statement. Set
TimeIntoInterval() to capture static data at 1 Hz. Capturing static data less
frequently is possible, but when doing so, only the latest static frequency sample
will be available.

CDM_VW300Static(CPIAddress, DestFreq, DestTherm, DestStdDev)

CDM_VW300RainFlow() obtains rainflow-histogram data. It is used in a slow
sequence.

CDM_VW300RainFlow(CPIAddress, RF1, RF2, RF3, RF4, RF5, RF6, RF7, RF8)

NOTE

User Manual

45

RainFlowSample() writes the rainflow-histogram data to a data table. A typical
rate for obtaining rainflow data is once per minute (60 s interval).

RainFlowSample(Source, DataType)

For more information, see the CRBasic Editor Help topics for each instruction.

Sample CRBasic programs for the CR3000 datalogger and CDM-VW300 and
CDM-VW305 combinations are listed in Appendix G, CRBasic Program Library.
These programs are examples and will likely need to be adapted for a specific
application.

CPISpeed() controls the speed of the CPI bus. Use of this instruction is optional.

CPISpeed(BitRate)

7.10.2 Sending Programs to the Datalogger

Several options are available for sending programs to dataloggers. Detailed
information can be found in the manuals for those options. Manuals are available
at www.campbellsci.com. Software options are preferred and assume that the
datalogger has an active communications link with a PC. The following
datalogger support software have Send Program utilities to send programs 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 the maximum and minimum
frequency response of a sensor (that is, what frequency values are returned when
the sensor experiences maximum and minimum phenomena or stimulus
conditions), the minimum and maximum frequency settings (LowFreq and
HighFreq in CRBasic CDM_VW300Config() instruction) can be used to
implement further noise reduction of the sensor response. For example, at 100 Hz,
the CDM-VW300 is capable of measuring frequencies between 580 and 6000 Hz.
However, if a sensor frequency will always fall between 2000 and 3000 Hz, even
for the lowest or highest reasonable readings, the minimum frequency (LowFreq)
can be set to 2000 Hz, and the maximum frequency (HighFreq) set to 3000 Hz.
The result will be that unwanted signals, such as noise, between 580 and 2000 Hz,
and between 3000 and 6000 Hz will be filtered out.

CDM-VW300 Series Dynamic Vibrating-Wire Analyzers

46

7.12 System Validation

7.12.1 Sensor Validation

Confirm sensors are working with the CDM-VW300 by using a USB connection
with DevConfig or DVWTool software. Status-indicating LED lights are provided
for each sensor channel — two on the CDM-VW300 and eight on the CDM­VW305. Table 7-5 lists meanings of these indicators.

Table 7-5. CDM-VW300 Channel-Status LED States

Flash green or red at 3 s interval

Channel set to actively measure.

Flash green

Response received from sensor.

Flash red

Diagnostic flags indicate there may
be a problem.

No flash, unlit

Channel not 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 available at www.campbellsci.com.

To use the tools for datalogger monitoring provided in RTDAQ or LoggerNet, start
the software and open a numeric display of the Public table (LoggerNet: Num
Display, RTDAQ: Monitor Data tab). In the Public table, observe the
frequencies or readings that correspond to the analyzer channels selected for
measurement. Figure 7-16 and Figure 7-17 shows a data displays in LoggerNet
and RTDAQ.

User Manual

47

Figure 7-16. LoggerNet connect screens showing frequencies from CDM-

VW300

CDM-VW300 Series Dynamic Vibrating-Wire Analyzers

48

Figure 7-17. RTDAQ screens showing frequencies in Public table

If proper frequencies are showing, 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

User Manual

49

sensors. The output data can be graphed on a line graph or in a rainflow
histogram. For more information, refer to Section 7.1.2, Using DVWTool.

7.12.2.1.1 Fault Detection

Fault indication are shown in Figure 7-18, Dynamic Vibrating-Wire Tool Box
Fault Indicators. A value other than 0x00 in the DVWTool Diagnostic Bits field

indicates a fault. The fault is emphasized by measurement results appearing in red
type, as illustrated in the following figure. Occasionally, the display of the
measurement values will also be flashing. A fault is accompanied by an
information icon (i inside a blue circle) in the Diagnotic Bits field. Click on the i
to view a short decription of the fault. An argument input error is indicted by a
red field and a ! inside a yellow triangle. Click on the ! to view a short description
of the error.

When the frequency of a sensor changes quickly (corresponding to rapid changes
of the phenomenon under test), the energy in the vibrating wire 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-amplitude
diagnostic codes that occur for long continuous periods require investigation.

See Section 8.5, Diagnostic Outputs, for more detail about the faults that are
displayed in the Diagnostic Bits field.

Figure 7-18. Dynamic Vibrating-Wire Tool Box Fault Indicators

8. Troubleshooting

CDM-VW300 series analyzers are designed to give years of trouble-free service
with reasonable care. However, if factory repair is needed, you must first contact
a Campbell Scientific application engineer to obtain an RMA (Return Materials
Authorization) number. See the Assistance statement at the beginning of this
manual for more information.

If the procedures in Section 6, Installation, do not lead to successful
measurements, review the following suggestions. If these suggestions do not

CDM-VW300 Series Dynamic Vibrating-Wire Analyzers

50

resolve the problem, please contact a Campbell Scientific application engineer.
Essential troubleshooting tools include a PC and a volt-ohm meter (multimeter).

8.1 Connections

Re-check all connections:

 Sensor wiring
 Analyzer wiring and connections
 Datalogger wiring and connections
 Communications interface and PC connections

8.2 Power

Use a volt meter to check that adequate power is provided to:

 CDM-VW300 analyzer
 SC-CPI communications interface
 Datalogger

8.3 Isolating Components

Isolating components is an effective troubleshooting strategy. The following
procedure isolates various components for independent verification.

1. Isolate the CDM-VW300 and sensors from the datalogger. Disconnect the

analyzer from the datalogger and connect it to a PC with DevConfig or
DVWTool software installed (ensure that the CDM-VW300 driver is installed
properly on the PC Windows® operating system before going to the field).

2. Attempt to measure sensors in the lab-mode configuration (refer to Section

6.1, Laboratory-Mode Installation).

If the above procedure results in successful measurements, the problem likely
resides with the datalogger. Otherwise, the problem likely resides with the CDM­VW300 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 LoggerNet.

4. If temperature and battery measurements in step 1 are successful, reconnect

the CDM-VW300 to the datalogger and send the 1 Hz program listed in
Appendix G.2, Static Measurements, to the datalogger. If the temperature and
battery measurement are unsuccessful, contact a Campbell Scientific
application engineer.

8.4 Filtering Harmonics

Occasionally, a sensor output can consistently report a harmonic instead of the
fundamental frequency. Most vibrating-wire sensors are designed such that
harmonic frequencies are much less prominent in the signal than the fundamental.
However, especially in worn or damaged sensors, harmonics can become a
significant part of wire motion. A knowledge of the spectral response of a sensor
will help set the maximum and minimum response frequencies properly. See
Section 7.11.1, Frequency Range, and Section 8.5.1.2, Calculating Low- and
High-Frequency Boundaries, for more details. If adjustment of max and min

User Manual

51

response settings does not remedy the problem, force the CDM-VW300 device to
re-assess the primary frequency by a) disabling and re-enabling a channel, or b)
re-sending the CRBasic program to the datalogger.

8.5 Diagnostic Outputs

Diagnostic outputs given by CDM-VW300 series analyzers include:

 Long integer diagnostic codes output at 20, 50, 100, 200 or 333.3 Hz for

each enabled channel.

 Standard deviation calculated from the dynamic readings output at 1 Hz

for each enabled channel.

8.5.1 Diagnostic Codes (Dynamic)

Diagnostic codes are returned with each dynamic frequency measurement made
by the CDM-VW300 analyzer. Each diagnostic code is a 32-bit unsigned integer
encoded with five diagnostic parameters. This method of reporting diagnostics
minimizes data sent over the CPI bus, which helps to maximize measurement
throughput rates. The five diagnostic parameters are:

1. Excitation strength

2. Low-amplitude warning flag

3. High-amplitude warning flag

4. Low-frequency warning flag

5. High-frequency warning flag

Each parameter is explained fully in Section 8.5.1.1, Description of Diagnostic
Parameters. The third argument of the CDM_VW300Dynamic() instruction
specifies the variable array to which the 32-bit diagnostic codes are written. This
array is dimensioned 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 Parameters

Excitation strength — reports the voltage applied by the CDM-VW300 analyzer
to keep the vibrating-wire of a sensor in motion. Excitation strength is reported as
bit values between 0 and 255, which represent excitation voltages between 0 and 6
V.

Excitation voltage is set indirectly by the user when the user enters
the Resonant Amplitude of the vibrating wire in DVWTool or the
ResonAmp parameter of the CDM_VW300Config() CRBasic
instruction. The excitation level is calculated by the analyzer and
applied each time a measurement is made.

To translate the bit value to volts, divide the bit value by 42.5. For example, an
excitation bit value of 180 is equivalent to an excitation voltage of 4.235 V. To
reduce the computational load on the datalogger processor, multiply the bit value
by the reciprocal of 42.5, which is 0.02353. A multiplication operation consumes
less datalogger processor time than a division operation, which is a consideration
in fast throughput applications. Results will be substantially the same as those
obtained by a division operation.

NOTE

CDM-VW300 Series Dynamic Vibrating-Wire Analyzers

52

Low-amplitude warning flag — flag is set true when the resonant amplitude of
the vibrating wire falls to or below 50% of the value entered in DVWTool or
CDM_VW300Config(). Resonant amplitude must be maintained higher than
50% to ensure an accurate measurement.

High-amplitude warning flag — flag is set true when the resonant amplitude of
the vibrating wire reaches or exceeds 200% of the value entered in DVWTool or
CDM_VW300Config(). Resonant amplitude must be maintained less than 200%
to ensure an accurate measurement.

Low-frequency warning flag — flag is set true when the frequency of the
vibrating wire falls between the Actual Min Freq (Hz) shown in DVWTool and
the Minimum Frequency (Hz) entered in DVWTool. The
CDM_VW300Config() instruction equivalent to Minimum Frequency (Hz) is
the LowFreq parameter. When a low-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 (Minimum Frequency or LowFreq) and
the frequency cut-off the analyzer can actually establish (Actual Min Freq). If a
measured frequency falls within the error band, the low-frequency warning flag is
set true. For example, if a low-frequency limit of 500 Hz is entered, and the
closest the analyzer can come to complying is to set the limit at 476.85 Hz, any
frequency below 476.85 Hz is discarded, and any frequency above 476.85 Hz is
used. However, any frequency between 476.85 Hz and 500 Hz will activate the
low-frequency warning flag, indicating that the data includes at least one
measurement below the user set limit. See Section 8.5.1.2, Calculating Low- and
High-Frequency Boundaries, for more information.

High-frequency warning flag — flag is set true when the frequency of the
vibrating 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 HighFreq)
and the frequency cut-off the analyzer can actually establish (Actual Max Freq).
If a measured frequency falls within the error band, the high-frequency warning
flag is set true. For example, if a high-frequency limit of 1000 Hz is entered, and
the closest the analyzer can come to complying is to set the limit at 1049.07 Hz,
any frequency above 1049.07 Hz is discarded, and any frequency below 1049.07
Hz is used. However, any frequency between 1000 Hz and 1049.07 Hz will
activate the high-frequency warning flag, indicating that the data include at least
one measurement above the user set limit. See Section 8.5.1.2, Calculating Low-
and High-Frequency Boundaries, for more information.

8.5.1.2 Calculating Low- and High-Frequency Boundaries

The easiest way to minimize the size of the low- and high-frequency error
windows is to enter estimated limits into the Minimum Frequency and
Maximum Frequency columns in the DVWTool main screen, record the resulting
values displayed in the Actual Min Freq and Actual Max Freq columns, then
turn around and enter those values back into the Minimum Frequency and

Maximum Frequency columns or the LowFreq and HighFreq parameters in the
CDM_VW300Config() CRBasic instruction.

However, to calculate the actual-minimum and actual-maximum frequencies, use
the information in Table 8-1 to size the value. For example, to calculate the
actual-minimum frequency, assuming a measurement is to be taken at a scan rate
of 20 Hz, use an integer multiple of 47.68 to calculate the actual-minimum
frequency. If the low-frequency limit is estimated to be 150 Hz, enter 3 x 47.68,

User Manual

53

or 143.04 Hz, as the Minimum Frequency in DVWTool or as the LowFreq
argument in the CDM_VW300Config() CRBasic instruction.

To calculate the actual-maximum frequency, assuming a measurement is to be
taken at a scan rate of 20 Hz, use an integer multiple of 47.68 to calculate the
actual-maximum frequency. If the high-frequency limit is estimated to be 500 Hz,
enter 10 x 47.68, or 476.80 Hz, as the Maximum Frequency in DVWTool or as
the HighFreq argument in the CDM_VW300Config() CRBasic instruction.

Table 8-1. Scan Rate and Boundary Resolution

Scan Rate (Hz)

Boundary Resolution (Hz)1

20

47.68

50

95.37

100

190.73

1

The low-frequency limit or the high-frequency limit must be an integer multiple of this frequency.

8.5.1.3 Using Diagnostic Parameters

Although a frequency reading may be provided when an amplitude or frequency
warning flag is true, the measurement should be accepted only with caution.
Rather than risk accepting bad data, consider setting the SysOptions argument of
the CDM_VW300Config() instruction to force the analyzer to report the
frequency measured under these conditions as NAN. A low- or high-amplitude
warning flag can be set for any one measurement, but not both. A low- or high­frequency 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 eight least-significant bits (20 through 27) of the diagnostic code represent the
excitation strength (0 to 255). When no low- or high-amplitude or frequency
warning flags are true, the diagnostic code has a value between 0 and 255. If
amplitude- or frequency-warning flags are set, the integer will be larger than 255.
To strip the warning flags out of the diagnostic code, a bit-masking operation is
performed.

The bit-masking operation uses the AND operator in CRBasic. The following
CRBasic statement decodes excitation strength in volts from the integer:

ExciteStrengthV = (DiagCode AND 255) / 42.5

where DiagCode is the diagnostic code and ExciteStrengthV is assigned a Float
data type. This ensures that only the eight least-significant bits are considered,
resulting in an intermediate value between 0 to 255 and a result between 0 and
6 V.

8.5.1.4.2 Low-Amplitude Warning Flag

The ninth bit (28 or 256) corresponds to the low-amplitude warning flag. Use the
following expression to isolate the state of this bit:

CDM-VW300 Series Dynamic Vibrating-Wire Analyzers

54

(DiagCode AND 256)

This expression results in zero if the bit is not set (in other words, low-amplitude
warning flag is false) and 256 if the bit is set (in other words, low-amplitude
warning flag is set true). Since many diagnostic codes are given each second, a
counter is normally used to track occasional instances of this flag being set. The
following CRBasic statement counts the number of times a low-amplitude
warning flag is set true.

If (DiagCode AND 256) Then LowAmpCount=LowAmpCount + 1

where LowAmpCount is assigned a Long data type. An alternative is to assign
the expression to a Boolean value. However, seeing the warning will be difficult
if it is set and reset too rapidly:

LowAmpWarning = (DiagCode AND 256)

where LowAmpWarning is assigned a Boolean data type.

8.5.1.4.3 High-Amplitude Warning Flag

The tenth bit (29 or 512) corresponds to the high-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 low­amplitude 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 AND 1024)

Similar techniques to those described in the preceding section for the low­amplitude warning flag can be used with this expression.

8.5.1.4.5 High-Frequency Warning Flag

The twelfth bit (211 or 2048) corresponds to the high-frequency warning flag and
can be isolated with this expression:

(DiagCode AND 2048)

Similar techniques to those described in the preceding section for the low­amplitude warning flag can be used with this expression.

8.5.1.4.6 Interpreting the Diagnostic Code

Although the above techniques constitute the preferred way for processing and
communicating the state of diagnostic parameters, examining the ranges of values
within which the returned code falls may be useful.

User Manual

55

The following table summarizes these ranges and their meaning:

Table 8-2. Diagnostic Code Ranges

If diagnostic

code falls

within this

range:

Low-

amplitude

warning

flag is:

High-

amplitude

warning

flag is:

Low-

frequency

warning

flag is:

High-

frequency

warning

flag is:

0 – 255

(0 – FF Hex)

256 – 511

(100 – 1FF Hex)

True

512 – 767

(200 – 2FF Hex)

True

1024 – 1279

(400 – 4FF Hex)

True

1280 – 1535

(500 – 5FF Hex)

True True

1536 – 1791

(600 – 6FF Hex)

True

True

2048 – 2303

(800 – 8FF Hex)

True

2304 – 2559

(900 – 9FF Hex)

True

True

2560 – 2815

(A00 – AFF

Hex)

True True

The excitation level associated with a diagnostic code can be calculated. This is
done by subtracting the low diagnostic code boundary value (shown in the first
column) from the raw diagnostic value and dividing the difference by 42.5. For
example, a raw diagnostic value of 1650 falls within the range 1536 to 1791.
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 readings can be
obtained from the output of the CDM_VW300Static() instruction. A significant
increase in standard deviation from a baseline may indicate a problem with either
the sensor or the structure or phenomena being measured. Take appropriate steps
to identify the source of any unexpected change in standard deviation.

8.6 Factory Default Reset

Products that use an operating system and memory may occasionally require a
reset to factory defaults. A default reset is probably near the end of the list of
troubleshooting techniques used when some aspect of a data-acquisition system is
not functioning or returning the expected results.

CDM-VW300 Series Dynamic Vibrating-Wire Analyzers

56

Use DevConfig to reset Campbell Scientific products to factory defaults. The
following procedure is a guide to resetting factory defaults. When resetting to
factory defaults, first preserve the current state of the device.

1. Connect the product to the PC. For the CDM-VW300 and SC-CPI interface,

connection is made via a male-USB to type-micro-B male USB cable.

2. To reset the product to factory defaults,
i. From the list at the left of the main DevConfig window, select the

product that was just physically connected. A series of tabs related
to the selected product is displayed.

ii. Select the Communication Port associated with the physical

connection.

iii. Click Connect. A series of tabs is presented. Select Settings

Editor.

iv. Save the old settings by clicking Summary, then Save in the lower

portion of the Settings Editor tab.

v. To reset factor defaults, click Factory Defaults, then click Apply.

9. Glossary

DevConfig — Device Configuration Utility. Use version 2.04 or later with
dynamic vibrating-wire data-acquisition systems. When DevConfig is installed,
USB drivers for CDM-VW300 series analyzers and the SC-CPI interface 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 and the SC­CPI interface are automatically sent to the PC. running Windows® XP, Windows®
Vista, Windows® 7, or Windows® 8 operating system

Datalogger support software — for the purposes of Campbell Scientific dynamic
vibrating-wire data-acquisition systems, this includes RTDAQ, LoggerNet, and
PC400. RTDAQ is preferred.

AWG — gauge. Units used when expressing the thickness of wire. The higher
the AWG value, the thinner the wire. 20 AWG to 24 AWG wire is often used in
all connections except power and earth ground. Power connections often use 16
AWG to 18 AWG wire. Earth ground connections usually use 14 AWG or larger
diameter.

NAN — not a number. An indication that an invalid measurement has been made.

10. References and Attributions

Matsuishi, M. and T. Endo, "Fatigue of Metals Subjected to Varying Loading,"
Japan Society of Mechanical Engineers, Fukuoka, Japan, 1968.

Israelsen, D. L., L. E. Jacobsen, J. A. Swenson, "Vibrating Wire Sensor Using
Spectral Analysis", U.S. Patent 7779690, Oct 24, 2010.

User Manual

57

Microsoft and Windows 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.

CDM-VW300 Series Dynamic Vibrating-Wire Analyzers

58

A-1

Appendix A. Measurement Theory

A.1 Dynamic Vibrating-Wire Measurements

The key components of standard, single-coil vibrating-wire sensors are 1) a taut
wire suspended between two anchor points, and 2) an electromagnetic coil
positioned at the centre of the wire. The coil serves two functions: first as an
actuator to put energy into the wire and, second, as a pickup to detect the motion
of the wire. Static vibrating-wire measurements are typically performed in a two­step process of exciting the wire and then measuring the wire response for a period
of time to determine its resonant frequency. The excitation waveform must be
spectrally broad, such as a swept-frequency sine wave, so as to provide sufficient
energy at the unknown resonant frequency of the wire. After the excitation, the
resonant motion of the wire is sampled, the frequency is determined, and then the
resonant energy dissipates prior to making the next measurement. The time
required for these steps typically limits this measurement method to rates slower
than 1 Hz.

Dynamic measurements 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 with a small amplitude can maintain the resonance
of the wire. If the excitation is not phase-aligned to the wire motion, then the
resonance will be dampened rather than reinforced. In between these excitation
windows, the wire motion can be sampled and the resonant frequency determined.
Using the newly calculated frequency, the excitation is adjusted slightly as needed
to track the changes in the resonant frequency of the wire. The excitation
mechanism has very fine frequency resolution to precisely track even very subtle
changes in the resonant frequency. As can be seen in Figure A-1, there are usually
only a few oscillation cycles of the wire available for determining the wire
resonant frequency. This difficulty is overcome by the spectral analysis
algorithm, which can determine the frequency of the wire precisely, even with this
short data sample.

Appendix A. Measurement Theory

A-2

Figure A-1. Timing of dynamic vibrating-wire measurements

An important aspect of dynamic measurement timing is synchronizing the process
to an external timing source that is independent of the wire oscillation.
Synchronization has intrinsic benefits to the measurement quality and also allows
simultaneous sampling of multiple channels. Figure A-1 shows that the
datalogger sample period dictates when the excitations are introduced and when
the frequency measurement is made. Since this sample period is independent of
the wire motion, the excitation may begin at any point in the phase of the
oscillation. When measuring single-coil sensors, inclusion of the excitation in the
measurement can skew the measured frequency and result in increased noise and a
diminished dynamic response. The remedy to excitation noise is synchronization,
which guarantees that the frequency measurement never overlaps the excitation
window. The multi-channel simultaneity enabled by time-synchronization 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 given once each
second. The same multiplier and offset apply to both the static and dynamic
frequency outputs.

Since only a few cycles of the wire are sampled each time a dynamic reading is
made (less than 50 ms, 20 ms, or 10 ms is available for sampling, depending on
the dynamic sample frequency used), the resolution in the spectrum is larger
(coarser) than the spectral resolution obtained when using all of the data captured
during a one-second period. As a result, there can occasionally be noise
frequencies that end up in the same FFT (Fast Fourier Transform) bin as the signal
of interest, causing measurement error. To detect such conditions, a static, one­second frequency is provided by the analyzer. This finer resolution reading can be
examined to detect and respond to cases such as those described above.

B-1

Appendix B. SC-CPI Datalogger to CPI
Interface

B.1 Introduction

The SC-CPI is designed to interface the CR3000, CR1000, and CR800
dataloggers to a network of CDMs (Campbell Distributed Modules) using the CPI
bus communications protocol. Only one SC-CPI interface is required per
datalogger. The datalogger and the SC-CPI should be installed in the same
enclosure.

B.2 Quickstart

The following figure shows SC-CPI to CR3000, CR1000, or CR800 series
datalogger connection wiring. Cable length should not exceed five feet.

SC-CPI module connects to terminals C1, C2, C3 (not the CR3000
SDM-C1, SDM-C2, SDM-C3).

B.3 Overview

The SC-CPI allows Campbell Scientific CR3000, CR1000, and CR800
dataloggers to interface to CDM modules. The datalogger communicates with the
SC-CPI module using control ports C1, C2 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 one
device to the other. Power can come from the datalogger, but may also be
provided by another source. A ground connection to the datalogger is required for
a reference for the data signals. A ground-wire connection from the ground lug to
a suitable ground should be made. Cabling between the datalogger and the SC­CPI should be as short as possible.

To configure the SC-CPI with a PC requires a software driver be installed on the
PC. This driver is automatically installed when DVWTool or DevConfig software
is installed. Once the driver is installed, a USB cable can be connected between

NOTE

Appendix B. SC-CPI Datalogger to CPI Interface

B-2

the PC and the SC-CPI. As indicated in Figure B-1, DevConfig can then be used
to check the SC-CPI OS version 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.

Appendix B. SC-CPI Datalogger to CPI Interface

B-3

B.4 Specifications

Compatibility

Dataloggers:

CR800 Series
CR1000
CR3000

Operating temperature:

–25° to 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)

Appendix B. SC-CPI Datalogger to CPI Interface

B-4

C-1

Appendix C. CDM Devices and CPI Bus

Campbell Scientific is introducing the CDM (Campbell Distributed Module) line
of peripherals, starting with the CDM-VW300 series of vibrating-wire analyzers.
As multiple CDM devices become available, they will be able to be networked to
communicate measurement information to a central datalogger. The
communications protocol used is the CAN (Controller Area Network) Peripheral
Interface (CPI) protocol.

CPI is a proprietary interface for communications between Campbell Scientific
dataloggers and Campbell Scientific CDM peripheral devices. It consists of a
physical layer definition and a data protocol. CDM devices are similar to
Campbell Scientific SDM devices in concept, but the use of the CPI bus enables
higher data-throughput rates and use of longer cables. CDM devices require more
power to operate in general than do SDM devices.

C.1 CDM Interconnection and Datalogger Connection

C.1.1 Power

The transmission of dc power to CDM modules is not governed by the CPI
specification but is left to the system integrator to implement. Most CDMs require
modest power from a regulated dc voltage between 11 and 32 Vdc. This power
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 longest
transmission distances. Ideally, four twisted-pair (data, synchronization, clock,
and ground) are contained in a single shielded cable.

The data pair carries data between the SC-CPI and CDM using the CAN protocol
with ISO 11898 as the electrical standard. The CAN protocol covers device
addressing, bus arbitration, prioritization, bit-error checking, and failed-message
retransmission. The synchronization pair uses the RS-485 (TIA/EIA-485A)
electrical standard. This signal is a pulse that marks the beginning of each scan.
CDMs use this precision timing to remain synchronized, to latch, and to buffer
and transmit data to the datalogger unprompted over the data pair.

Use a pn #28558 termination resistor plug (included with the pn #29370 CPI
network kit) on the final device of a CPI chain to ensure cable communications are
working at high speeds and over very long distances. CPI pin assignments are
provided in the following figure as implemented with Cat5e cabling.

Appendix C. CDM Devices and CPI Bus

C-2

Figure C-1. CPI pin assignments

C.1.3 Speed as a Function of Distance

Table C-1. Maximum Potential Speed as a Function of Distance1

Bit Rate (kbps)

Cable Length, m (ft)

1000

45 (150)

500

91 (300)

250

182 (600)

125

365 (1200)

50

914 (3000)

25

1219 (4000)

1

for a two-node CDM network under optimal conditions

Cable lengths shown in the preceding table can usually be adapted to CPI
networks containing multiple CDM devices if the total distance for all cable in a
network does not exceed the given length.

For most CPI bus deployments, all CDM devices should be set with 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 SC­CPI 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
CDM device that is set to a bit rate that differs from the current SC-CPI setting
will not operate on the CPI network, and the COMM Status indicator light on the
CDM device will flash red.

1

The SC-CPI interface and all CDM devices can be configured using Campbell Scientific
Device Configuration Utility (DevConfig). CDM-VW300 series analyzers can also be
configured using DVWTool software.

Appendix C. CDM Devices and CPI Bus

C-3

C.1.4 CPI Grounding

To keep the common mode of the signals in range, a common reference (ground)
connection is advised for any non-isolated communication link. If a ground
potential difference exists, then current will flow on the common wire from one
end of the cable to the other. This current is restricted only by the dc resistance of
the common wire which is often quite low. To increase this resistance, a 100-Ω
resistor is placed inside each CDM device, SC-CPI interface, or CDM equipped
datalogger between the CPI ground and the local ground. This is a compromise
between directly connecting the two points and leaving the common connection
entirely disconnected. It limits current while still helping to prevent the two node
voltage potentials from drifting too far apart.

C.1.6 Addressing

The CPI bus uses an addressing scheme that supports up to 120 CDM devices on
the bus connected to a single SC-CPI interface. In the case of the CDM-VW300,
fewer devices must be used because of limitations of bandwidth caused by high­speed measurement rates. Future CDM devices may be used on a CPI bus
managed by a SC-CPI interface device connected to a datalogger.

C.2 Distributed 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 device. The network kit supplied with each CDM device
provides yellow tape with which to optionally mark RJ45cables dedicated to CPI
communications.

A single CDM device can be connected to a CR800 series, CR1000, or CR3000
datalogger using an SC-CPI interface. One CPI port on the CDM device connects
to a CPI port on the SC-CPI. The other CPI port is terminated with a CPI
terminator (supplied with pn #29370 network kit). When multiple CDM devices
are used in a daisy-chain topology, one CPI port of the CDM device nearest the
datalogger connects to the SC-CPI interface and the other CPI port connects to a
neighbouring CDM device. Any CDM devices in the middle of the chain will
have both CPI ports connected to neighbouring CDM devices. Once CPI port of
the CDM device at the end of the CPI bus/chain connects to a neighbouring CPI
device, and the other port is fitted with a termination plug (pn #28558). Contact a
Campbell Scientific application engineer for information about using an optional
star topology.

Appendix C. CDM Devices and CPI Bus

C-4

Figure C-2. Long cable lengths of a distributed CPI bus

D-1

Appendix D. Digits Conversion

Vibrating-wire sensors are typically supplied with a calibration report from the
manufacturer. Use the calibration data to convert the frequency output of the
CDM-VW300 to engineering units. While basic measurement of CDM-VW300
analyzers is frequency, which is expressed in hertz (Hz), some calibration reports
express the base measurement in terms of 'digits'. If this is the case, first convert
the frequency output of the CDM-VW300 to a digits equivalent using the
following formula,

digits = Hz2 / 1000.

Use gauge factor and polynomial 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 shows the calibration report for
the sensor. The relationship of sensor output to displacement, s, is expressed as,

s = (3.598e–9) • digits2 + (1.202e–3) • digits + (–3.1682)

First, 2400 Hz is converted to digits using the following formula:

digits = (2400 Hz) 2 / 1000 = 5760

Next, the digits value is placed in the polynomial equation:

s = (9.139E–08) • (5760)2 + (0.03054) • 5760 + (–80.471)

s = 98.53 mm

Appendix D. Digits Conversion

D-2

Figure D-1. Geokon Calibration Report of a Sensor without a Thermistor

E-1

Appendix E. Calculating Measurement
Error

When using a CDM-VW300 analyzer, the basic output of a measurement is
frequency (Hz) or frequency squared (Hz2). Vibrating-wire sensors are usually
designed with a linear relationship between wire tension and the phenomenon
being measured. Further, wire tension usually has a linear relationship to the
square of the resonant frequency (f2). Manufacturers typically provide a formula
for converting frequency to an engineering unit (UE) in the form,

UE = Kf2, Eq. 1

where K is a constant determined from sensor specifications.

So, for a very small change in frequency, ∆f, change in output, ∆UE, is given by,

∆U

E

= 2Kf∆f Eq. 2

where Eq. 2 is obtained by taking the first derivative of Eq.1 with respect to f, and
f is 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 using a Geokon strain gauge, constant K is given by,

K = GB / 1000

Where G is the gauge factor 4.062 or 0.391, dependent on gauge type, and B is a
batch factor (a number usually near 1, such as 0.97), given on the sensor
calibration sheet.

Substituting into Eq. 1 using engineering units of microstrain (µε):

µε = GBf

2

/ 1000,

The effective resolution, Re, of the output, or ∆µε, is:

∆µε = 2GBfN / 1000

or

∆µε = GBfN / 500,

where N is the noise value given in Table 5-3, CDM-VW300/305 Effective
Frequency Measurement Resolution, corresponding to the sample rate being used.

Appendix E. Calculating Measurement Error

E-2

E.2 Example Error Calculation: DGSI Embedment

Strain Gauge

For Durham Geo Slope Indicator embedment strain gauges, K = G, where G =

4.0624E–03.

So, for microstrain,

µε = Gf

2

And for effective resolution,

∆ µε = 2GfN

E.3 Example Error Calculation: DGSI Spot-Welded

Strain Gauge

For Durham Geo Slope Indicator spot-welded strain gauges,

µε = Af

2

+ C

Where A = 7.576E–04 and C = –2030.1

So, K = A, and the above formula stands as it is for specifying the output.

When calculating the effective 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 sensor. During a short measurement interval, the assumption is made that
there is no change in the temperature of the sensor. So, for small changes in
sensor displacement, K is assumed to be constant, and the Kt term is ignored when
calculating the output error. The resulting equation is,

∆s = 2GfN / 1000

or

∆s = GfN / 500

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
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

Appendix E. Calculating Measurement Error

E-4

F-1

Appendix F. Thermistor Information

F.1 Converting Resistance to Temperature

The CDM-VW300 outputs a resistance value for sensors that contain a thermistor.
Temperature is normally calculated by applying the resistance to the Steinhart­Hart equation, which converts resistance to temperature.

The Steinhart-Hart equation for converting resistance to degree Celsius is as
follows:

Temperature = 1/(A + B • LN(resistance) + C • (LN(resistance))^3) - 273.15

Where A, B, and C are coefficients for the Steinhart-Hart equation.

The coefficients for the Steinhart-Hart equation are specific to the thermistor
contained in your sensor and are obtained from the 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(resistance))^3) – 273.15

If the measured resistance is 2221 Ω, the calculated temperature in degree Celsius
is:

Temperature = 1/(1.4051E–03 + 2.369E–04 • LN(2221) +

1.019E–07 • (LN(2221))^3) – 273.15

Temperature = 31.98°C

F.2 Accuracy and Resolution

The accuracy of the temperature measurement is a function of the following
factors:

1. Thermistor interchangeability

2. Resistance of the wire

3. Steinhart-Hart equation error

4. Precision of the bridge resistors

NOTE

Appendix F. Thermistor Information

F-2

5. Accuracy of the datalogger voltage measurement

6. Temperature coefficient of the bridge resistors

Errors three through six are usually sufficiently small that they can be ignored.
The wire resistance is primarily an offset error 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 a

function of lead length. Wire is 22 AWG with 16 ohms per 1000 feet.

Appendix F. Thermistor 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.

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.

G-1

Appendix G. CRBasic Program Library

The following example programs are compatible with CR3000, CR1000, and
CR800 dataloggers without modification. The programs are available for
download at www.campbellsci.com/downloads. Look for "CDM-VW300
Example Programs." The programs are named with a .CR3 extension and can be
renamed as .CR1 or .CR8 without modification to run on the CR1000 or CR800
dataloggers. To use programs from this library,

1. Select the desired program and save it to your PC.

2. Open CRBasic Editor.

3. Open the program file just downloaded to edit, if necessary.

4. Send the program to the datalogger using the program Send command in

RTDAQ or LoggerNet.

5. Monitor the operation of the system with the numeric and graphical

monitors available with RTDAQ or LoggerNet.

G.1 Dynamic Measurements

G.1.1 20 Hz Measurement Example — One CDM-VW300, Two

Channels

'===20Hz-1Device2Ch_4-25-13.CR3===
'CR3000 datalogger
'CDM-VW300 vibrating-wire analyzer
'Program to read 20 Hz dynamic data from one CDM-VW300 analyzer measuring two channels

'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

Public Freq(2) 'dynamic 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=0) only those channels which have sensors connected

Dim Enable(2) As Long = { 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(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}

'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(2) As Long = { 0, 0}

'Multiplier (factor) to be applied to sensor output frequency

Dim Mult(2) = { 1.0, 1.0}

'Offset (shift) to be applied to sensor output frequency

Dim Off(2) = { 0.0, 0.0}

'Steinhart-Hart coefficients [A,B,C] for converting thermistor ohms to
'temperature in Celsius. Specifying zeroes for A,B,C results in a reading in Ohms.

Dim SteinA(2) = { 0.0, 0.0}
Dim SteinB(2) = { 0.0, 0.0}

Appendix G. CRBasic Program Library

G-2

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_AMP(),F_Low(),F_High(), _

OutForm(),Mult(),Off(), SteinA(),SteinB(),SteinC(), _
RFMB(),RFAB(),RFLL(),RFHL(),RFHY(),RFOF())

DataTable (static,true,-1)

'Static Frequency reading (1 Hz output)
Sample (2,StaticFreq(),IEEE4)
'Thermistor reading : Ohms or DegC
Sample (2,Therm(),IEEE4)
'Standard Deviation of dynamic readings
'taken during the most recent second
Sample (2,DynStdDev(),IEEE4)

EndTable

DataTable (dynamic,true,-1)

'Dynamic Frequency (20 Hz output)
Sample (2,Freq(),IEEE4)
'Diagnostic code for the current dynamic reading
Sample (2,Diag(),IEEE4)

EndTable

BeginProg

'20 Hz/50msec scan rate
Scan(50,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.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 line matches the address
'reported for the attached analyzer in the DevConfig or DVWTool software.

Const CPI_ADDR = 1 '<<<<<<<<<<<<<<SET CPI ADDRESS HERE

Public Freq(8) 'dynamic frequencies
Public Diag(8) As Long 'diagnostic code

Public StaticFreq(8) 'Static (1Hz output) frequencies
Public Therm(8) 'Thermistor readings

'Standard Deviation of the dynamic readings that occurred during the latest one-second interval

Public DynStdDev(8)

'The following arrays are used to configure the 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(8) = { 0.002, 0.002, 0.002, 0.002, 0.002, 0.002, 0.002, 0.002}

Appendix G. CRBasic Program Library

G-3

'Low Frequency Boundary (sensor frequency should never fall below
'this value regardless of environmental changes)

Dim F_Low(8) = { 300, 300, 300, 300, 300, 300, 300, 300}

'High Frequency Boundary (sensor frequency should never exceed
'this value regardless of environmental changes)

Dim F_High(8) = { 6000, 6000, 6000, 6000, 6000, 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}

'Steinhart-Hart coefficients [A,B,C] for converting thermistor ohms to
'temperature in Celsius. Specifying zeroes for A,B,C results in a reading in Ohms.

Dim SteinA(8) = { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0}
Dim SteinB(8) = { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0}
Dim SteinC(8) = { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0}

'Rainflow configuration (not used in this program, 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, 400.0}
Dim RFHL(8) = {4000.0,4000.0,4000.0,4000.0,4000.0,4000.0,4000.0,4000.0}
Dim RFHY(8) = { 0.005, 0.005, 0.005, 0.005, 0.005, 0.005, 0.005, 0.005}
Dim RFOF(8) As Long = { 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 dynamic readings taken during the most recent second
Sample (8,DynStdDev(),IEEE4)

EndTable

DataTable (dynamic,true,-1)

'Dynamic Frequency (20Hz output)
Sample (8,Freq(),IEEE4)
'Diagnostic code for the current dynamic reading
Sample (8,Diag(),IEEE4)

EndTable

BeginProg

'20 Hz/50msec scan rate
Scan(50,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.1.3 20 Hz Measurement Example — Three CDM-VW305s, 24

Channels

'===20Hz-3Devices8Ch_3-25-13.CR3===
'CR3000 datalogger
'CDM-VW305 vibrating-wire analyzer
'Program to read 20-Hz dynamic data from three CDM-VW305 analyzers (8x3=24 channels)

'IMPORTANT -- Ensure that the CPI addresses coded on the following lines matches the addresses
'reported for each attached analyzer in the DevConfig or DVWTool software.

Const CPI_ADDR1 = 5
Const CPI_ADDR2 = 15
Const CPI_ADDR3 = 25

Public Freq1(8), Freq2(8), Freq3(8) 'dynamic frequencies
Public Diag1(8) As Long, Diag2(8) As Long, Diag3(8) As Long 'diagnostic codes

Public StaticFreq1(8), StaticFreq2(8), StaticFreq3(8) 'Static (1Hz output) frequencies

Appendix G. CRBasic Program Library

G-4

Public Therm1(8), Therm2(8), Therm3(8) 'Thermistor readings
Public DynStdDev1(8), DynStdDev2(8), DynStdDev3(8) 'Dynamic Standard Deviations

'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, 0.002, 0.002, 0.002, 0.002}
Dim F_Low1(8) = { 300, 300, 300, 300, 300, 300, 300, 300}
Dim F_High1(8) = { 6000, 6000, 6000, 6000, 6000, 6000, 6000, 6000}
Dim OutForm1(8) As Long = { 0, 0, 0, 0, 0, 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}
Dim F_High2(8) = { 6000, 6000, 6000, 6000, 6000, 6000, 6000, 6000}
Dim OutForm2(8) As Long = { 0, 0, 0, 0, 0, 0, 0, 0}
Dim Mult2(8) = { 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0}
Dim Off2(8) = { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0}
Dim SteinA2(8) = { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0}
Dim SteinB2(8) = { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0}
Dim SteinC2(8) = { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0}

'Setup for Third Device

Dim Enable3(8) As Long = { 1, 1, 1, 1, 1, 1, 1, 1}
Dim Max_AMP3(8) = { 0.002, 0.002, 0.002, 0.002, 0.002, 0.002, 0.002, 0.002}
Dim F_Low3(8) = { 300, 300, 300, 300, 300, 300, 300, 300}
Dim F_High3(8) = { 6000, 6000, 6000, 6000, 6000, 6000, 6000, 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 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, 400.0}
Dim RFHL(8) = {4000.0,4000.0,4000.0,4000.0,4000.0,4000.0,4000.0,4000.0}
Dim RFHY(8) = { 0.005, 0.005, 0.005, 0.005, 0.005, 0.005, 0.005, 0.005}
Dim RFOF(8) As Long = { 100, 100, 100, 100, 100, 100, 100, 100}

'Configure First Device

CDM_VW300Config(1,CPI_ADDR1,0,Enable1(),Max_AMP1(),F_Low1(),F_High1(), _

OutForm1(),Mult1(),Off1(), SteinA1(),SteinB1(),SteinC1(), _
RFMB(),RFAB(),RFLL(),RFHL(),RFHY(),RFOF())

'Configure Second Device

CDM_VW300Config(1,CPI_ADDR2,0,Enable2(),Max_AMP2(),F_Low2(),F_High2(), _

OutForm2(),Mult2(),Off2(), SteinA2(),SteinB2(),SteinC2(), _
RFMB(),RFAB(),RFLL(),RFHL(),RFHY(),RFOF())

'Configure Third Device

CDM_VW300Config(1,CPI_ADDR3,0,Enable3(),Max_AMP3(),F_Low3(),F_High3(), _

OutForm3(),Mult3(),Off3(), SteinA3(),SteinB3(),SteinC3(), _
RFMB(),RFAB(),RFLL(),RFHL(),RFHY(),RFOF())

DataTable (static,true,-1)

Sample (8,StaticFreq1(),IEEE4)
Sample (8,Therm1(),IEEE4)
Sample (8,DynStdDev1(),IEEE4)
Sample (8,StaticFreq2(),IEEE4)
Sample (8,Therm2(),IEEE4)
Sample (8,DynStdDev2(),IEEE4)
Sample (8,StaticFreq3(),IEEE4)
Sample (8,Therm3(),IEEE4)
Sample (8,DynStdDev3(),IEEE4)

EndTable

DataTable (dynamic,true,-1)

Sample (8,Freq1(),IEEE4)
Sample (8,Diag1(),IEEE4)
Sample (8,Freq2(),IEEE4)
Sample (8,Diag2(),IEEE4)
Sample (8,Freq3(),IEEE4)
Sample (8,Diag3(),IEEE4)

EndTable

BeginProg

Appendix G. CRBasic Program Library

G-5

'20 Hz/50msec scan rate
Scan(50,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,StaticFreq3(),Therm3(),DynStdDev3())
CallTable static
EndIf

NextScan

EndProg

G.1.4 20 Hz Measurement Example — Six CDM-VW305s, 48

Channels

'===20Hz-6Devices8Ch_4-25-13.CR3===
'CR3000 datalogger
'CDM-VW305 vibrating-wire analyzer
'Program to read 20-Hz dynamic data from six CDM-VW305 analyzers (8x6=48 channels)

'IMPORTANT -- Ensure that the CPI addresses coded on the following lines matches the addresses
'reported for each attached analyzer in the DevConfig or DVWTool software.

Const CPI_ADDR1 = 5 '<<<<<<<<<<<<<<SET CPI ADDRESSES HERE
Const CPI_ADDR2 = 15
Const CPI_ADDR3 = 25
Const CPI_ADDR4 = 35
Const CPI_ADDR5 = 45
Const CPI_ADDR6 = 55

Public Freq1(8), Freq2(8), Freq3(8) 'dynamic frequencies
Public Freq4(8), Freq5(8), Freq6(8)
Public Diag1(8) As Long, Diag2(8) As Long, Diag3(8) As Long 'diagnostic codes
Public Diag4(8) As Long, Diag5(8) As Long, Diag6(8) As Long

Public StaticFreq1(8), StaticFreq2(8), StaticFreq3(8) 'Static (1-Hz output) frequencies
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, 0.002, 0.002, 0.002, 0.002}
Dim F_Low1(8) = { 300, 300, 300, 300, 300, 300, 300, 300}
Dim F_High1(8) = { 6000, 6000, 6000, 6000, 6000, 6000, 6000, 6000}
Dim OutForm1(8) As Long = { 0, 0, 0, 0, 0, 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}
Dim F_High2(8) = { 6000, 6000, 6000, 6000, 6000, 6000, 6000, 6000}
Dim OutForm2(8) As Long = { 0, 0, 0, 0, 0, 0, 0, 0}
Dim Mult2(8) = { 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0}
Dim Off2(8) = { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0}
Dim SteinA2(8) = { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0}
Dim SteinB2(8) = { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0}
Dim SteinC2(8) = { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0}

'Setup for Third Device

Dim Enable3(8) As Long = { 1, 1, 1, 1, 1, 1, 1, 1}
Dim Max_AMP3(8) = { 0.002, 0.002, 0.002, 0.002, 0.002, 0.002, 0.002, 0.002}
Dim F_Low3(8) = { 300, 300, 300, 300, 300, 300, 300, 300}
Dim F_High3(8) = { 6000, 6000, 6000, 6000, 6000, 6000, 6000, 6000}

Appendix G. CRBasic Program Library

G-6

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}

'Setup for Fourth Device

Dim Enable4(8) As Long = { 1, 1, 1, 1, 1, 1, 1, 1}
Dim Max_AMP4(8) = { 0.002, 0.002, 0.002, 0.002, 0.002, 0.002, 0.002, 0.002}
Dim F_Low4(8) = { 300, 300, 300, 300, 300, 300, 300, 300}
Dim F_High4(8) = { 6000, 6000, 6000, 6000, 6000, 6000, 6000, 6000}
Dim OutForm4(8) As Long = { 0, 0, 0, 0, 0, 0, 0, 0}
Dim Mult4(8) = { 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0}
Dim Off4(8) = { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0}
Dim SteinA4(8) = { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0}
Dim SteinB4(8) = { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0}
Dim SteinC4(8) = { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0}

'Setup for Fifth Device

Dim Enable5(8) As Long = { 1, 1, 1, 1, 1, 1, 1, 1}
Dim Max_AMP5(8) = { 0.002, 0.002, 0.002, 0.002, 0.002, 0.002, 0.002, 0.002}
Dim F_Low5(8) = { 300, 300, 300, 300, 300, 300, 300, 300}
Dim F_High5(8) = { 6000, 6000, 6000, 6000, 6000, 6000, 6000, 6000}
Dim OutForm5(8) As Long = { 0, 0, 0, 0, 0, 0, 0, 0}
Dim Mult5(8) = { 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0}
Dim Off5(8) = { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0}
Dim SteinA5(8) = { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0}
Dim SteinB5(8) = { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0}
Dim SteinC5(8) = { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0}

'Setup for Sixth Device

Dim Enable6(8) As Long = { 1, 1, 1, 1, 1, 1, 1, 1}
Dim Max_AMP6(8) = { 0.002, 0.002, 0.002, 0.002, 0.002, 0.002, 0.002, 0.002}
Dim F_Low6(8) = { 300, 300, 300, 300, 300, 300, 300, 300}
Dim F_High6(8) = { 6000, 6000, 6000, 6000, 6000, 6000, 6000, 6000}
Dim OutForm6(8) As Long = { 0, 0, 0, 0, 0, 0, 0, 0}
Dim Mult6(8) = { 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0}
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, 400.0}
Dim RFHL(8) = {4000.0,4000.0,4000.0,4000.0,4000.0,4000.0,4000.0,4000.0}
Dim RFHY(8) = { 0.005, 0.005, 0.005, 0.005, 0.005, 0.005, 0.005, 0.005}
Dim RFOF(8) As Long = { 100, 100, 100, 100, 100, 100, 100, 100}

'Configure First Device

CDM_VW300Config(1,CPI_ADDR1,0,Enable1(),Max_AMP1(),F_Low1(),F_High1(), _

OutForm1(),Mult1(),Off1(), SteinA1(),SteinB1(),SteinC1(), _
RFMB(),RFAB(),RFLL(),RFHL(),RFHY(),RFOF())

'Configure Second Device

CDM_VW300Config(1,CPI_ADDR2,0,Enable2(),Max_AMP2(),F_Low2(),F_High2(), _

OutForm2(),Mult2(),Off2(), SteinA2(),SteinB2(),SteinC2(), _
RFMB(),RFAB(),RFLL(),RFHL(),RFHY(),RFOF())

'Configure Third Device

CDM_VW300Config(1,CPI_ADDR3,0,Enable3(),Max_AMP3(),F_Low3(),F_High3(), _

OutForm3(),Mult3(),Off3(), SteinA3(),SteinB3(),SteinC3(), _
RFMB(),RFAB(),RFLL(),RFHL(),RFHY(),RFOF())

'Configure Fourth Device

CDM_VW300Config(1,CPI_ADDR4,0,Enable4(),Max_AMP4(),F_Low4(),F_High4(), _

OutForm4(),Mult4(),Off4(), SteinA4(),SteinB4(),SteinC4(), _
RFMB(),RFAB(),RFLL(),RFHL(),RFHY(),RFOF())

'Configure Fifth Device

CDM_VW300Config(1,CPI_ADDR5,0,Enable5(),Max_AMP5(),F_Low5(),F_High5(), _

OutForm5(),Mult5(),Off5(), SteinA5(),SteinB5(),SteinC5(), _
RFMB(),RFAB(),RFLL(),RFHL(),RFHY(),RFOF())

'Configure Sixth Device

CDM_VW300Config(1,CPI_ADDR6,0,Enable6(),Max_AMP6(),F_Low6(),F _High6(), _

OutForm6(),Mult6(),Off6(), SteinA6(),SteinB6(),SteinC6(), _
RFMB(),RFAB(),RFLL(),RFHL(),RFHY(),RFOF())

DataTable (static,true,-1)

Sample (8,StaticFreq1(),IEEE4)
Sample (8,Therm1(),IEEE4)
Sample (8,DynStdDev1(),IEEE4)
Sample (8,StaticFreq2(),IEEE4)
Sample (8,Therm2(),IEEE4)
Sample (8,DynStdDev2(),IEEE4)
Sample (8,StaticFreq3(),IEEE4)
Sample (8,Therm3(),IEEE4)

Appendix G. CRBasic Program Library

G-7

Sample (8,DynStdDev3(),IEEE4)
Sample (8,StaticFreq4(),IEEE4)
Sample (8,Therm4(),IEEE4)
Sample (8,DynStdDev4(),IEEE4)
Sample (8,StaticFreq5(),IEEE4)
Sample (8,Therm5(),IEEE4)
Sample (8,DynStdDev5(),IEEE4)
Sample (8,StaticFreq6(),IEEE4)
Sample (8,Therm6(),IEEE4)
Sample (8,DynStdDev6(),IEEE4)

EndTable

DataTable (dynamic,true,-1)

Sample (8,Freq1(),IEEE4)
Sample (8,Diag1(),IEEE4)
Sample (8,Freq2(),IEEE4)
Sample (8,Diag2(),IEEE4)
Sample (8,Freq3(),IEEE4)
Sample (8,Diag3(),IEEE4)
Sample (8,Freq4(),IEEE4)
Sample (8,Diag4(),IEEE4)
Sample (8,Freq5(),IEEE4)
Sample (8,Diag5(),IEEE4)
Sample (8,Freq6(),IEEE4)
Sample (8,Diag6(),IEEE4)

EndTable

BeginProg

'20 Hz/50msec scan rate
Scan(50,msec,500,0)

CDM_VW300Dynamic(CPI_ADDR1,Freq1(),Diag1()) 'Get dynamic readings
CDM_VW300Dynamic(CPI_ADDR2,Freq2(),Diag2())
CDM_VW300Dynamic(CPI_ADDR3,Freq3(),Diag3())
CDM_VW300Dynamic(CPI_ADDR4,Freq4(),Diag4())
CDM_VW300Dynamic(CPI_ADDR5,Freq5(),Diag5())
CDM_VW300Dynamic(CPI_ADDR6,Freq6(),Diag6())
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,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.CR3===
'CR3000 datalogger
'CDM-VW300 vibrating-wire analyzer
'Program to read 50-Hz dynamic data from one CDM-VW300 analyzer measuring two channels

'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

Public Freq(2) 'dynamic frequencies
Public Diag(2) As Long 'diagnostic code

Public StaticFreq(2) 'Static (1Hz 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 series device. Refer to the
'CDM_VW300Config instruction used below.
'
' CH1 CH2
' --- --­'Set to true (Enabled=1, Disabled=0) only those channels which have sensors connected

Appendix G. CRBasic Program Library

G-8

Dim Enable(2) As Long = { 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(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}

'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(2) As Long = { 0, 0}

'Multiplier (factor) to be applied to sensor output frequency

Dim Mult(2) = { 1.0, 1.0}

'Offset (shift) to be applied to sensor output frequency

Dim Off(2) = { 0.0, 0.0}

'Steinhart-Hart coefficients [A,B,C] for converting thermistor ohms to
'temperature in Celsius. Specifying zeroes for A,B,C results in a reading in Ohms.

Dim SteinA(2) = { 0.0, 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_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 (2,StaticFreq(),IEEE4)
'Thermistor reading : Ohms or DegC
Sample (2,Therm(),IEEE4)
'Standard Deviation of dynamic readings
'taken during the most recent second
Sample (2,DynStdDev(),IEEE4)

EndTable

DataTable (dynamic,true,-1)

'Dynamic Frequency (50Hz output)
Sample (2,Freq(),IEEE4)
'Diagnostic code for the current dynamic reading
Sample (2,Diag(),IEEE4)

EndTable

BeginProg

'50 Hz/20msec scan rate
Scan(20,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

Appendix G. CRBasic Program Library

G-9

G.1.6 50 Hz Measurement Example — One CDM-VW305, Eight

Channels

'===50Hz-1Device8Ch_3-25-13.CR3===
'CR3000 datalogger
'CDM-VW305 vibrating-wire analyzer
'Program to read 50-Hz dynamic data from one CDM-VW305 analyzer measuring eight channels

'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

Public Freq(8) 'dynamic frequencies
Public Diag(8) As Long 'diagnostic code

Public StaticFreq(8) 'Static (1Hz output) frequencies
Public Therm(8) 'Thermistor readings

'Standard Deviation of the dynamic
'readings that occurred during the latest
'1 second interval

Public DynStdDev(8)

'The following arrays are used to configure the 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(8) = { 0.002, 0.002, 0.002, 0.002, 0.002, 0.002, 0.002, 0.002}

'Low-Frequency Boundary (sensor frequency should never fall below
'this value regardless of environmental changes)

Dim F_Low(8) = { 300, 300, 300, 300, 300, 300, 300, 300}

'High-Frequency Boundary (sensor frequency should never exceed
'this value regardless of environmental changes)

Dim F_High(8) = { 6000, 6000, 6000, 6000, 6000, 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}

'Steinhart-Hart coefficients [A,B,C] for converting thermistor ohms to
'temperature in Celsius. Specifying zeroes for A,B,C results in a reading in Ohms.

Dim SteinA(8) = { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0}
Dim SteinB(8) = { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0}
Dim SteinC(8) = { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0}

'Rainflow configuration (not used in this program, 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, 400.0}
Dim RFHL(8) = {4000.0,4000.0,4000.0,4000.0,4000.0,4000.0,4000.0,4000.0}
Dim RFHY(8) = { 0.005, 0.005, 0.005, 0.005, 0.005, 0.005, 0.005, 0.005}
Dim RFOF(8) As Long = { 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 dynamic readings taken during the most recent second.
Sample (8,DynStdDev(),IEEE4)

EndTable

DataTable (dynamic,true,-1)

'Dynamic Frequency (50Hz output)
Sample (8,Freq(),IEEE4)
'Diagnostic code for the current dynamic reading.
Sample (8,Diag(),IEEE4)

EndTable

BeginProg

'50 Hz/20msec scan rate

Appendix G. CRBasic Program Library

G-10

Scan(20,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.1.7 50 Hz Measurement Example — Three CDM-VW305s, 24

Channels

'===50Hz-3Devices8Ch_4-25-13.CR3===
'CR3000 datalogger
'CDM-VW305 vibrating-wire analyzer
'Program to read 50-Hz dynamic data from three CDM-VW305 analyzers (8x3=24 channels)

'IMPORTANT -- Ensure that the CPI addresses coded on the following lines matches the addresses
'reported for each attached analyzer in the DevConfig or DVWTool software.

Const CPI_ADDR1 = 5 '<<<<<<<<<<<<<<SET CPI ADDRESSES HERE
Const CPI_ADDR2 = 15
Const CPI_ADDR3 = 25

Public Freq1(8), Freq2(8), Freq3(8) 'dynamic frequencies
Public Diag1(8) As Long, Diag2(8) As Long, Diag3(8) As Long 'diagnostic codes

Public StaticFreq1(8), StaticFreq2(8), StaticFreq3(8) 'Static (1Hz output) frequencies
Public Therm1(8), Therm2(8), Therm3(8) 'Thermistor readings
Public DynStdDev1(8), DynStdDev2(8), DynStdDev3(8) 'Dynamic Standard Deviations

'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, 0.002, 0.002, 0.002, 0.002}
Dim F_Low1(8) = { 300, 300, 300, 300, 300, 300, 300, 300}
Dim F_High1(8) = { 6000, 6000, 6000, 6000, 6000, 6000, 6000, 6000}
Dim OutForm1(8) As Long = { 0, 0, 0, 0, 0, 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}
Dim F_High2(8) = { 6000, 6000, 6000, 6000, 6000, 6000, 6000, 6000}
Dim OutForm2(8) As Long = { 0, 0, 0, 0, 0, 0, 0, 0}
Dim Mult2(8) = { 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0}
Dim Off2(8) = { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0}
Dim SteinA2(8) = { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0}
Dim SteinB2(8) = { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0}
Dim SteinC2(8) = { 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0}

'Setup for Third Device

Dim Enable3(8) As Long = { 1, 1, 1, 1, 1, 1, 1, 1}
Dim Max_AMP3(8) = { 0.002, 0.002, 0.002, 0.002, 0.002, 0.002, 0.002, 0.002}
Dim F_Low3(8) = { 300, 300, 300, 300, 300, 300, 300, 300}
Dim F_High3(8) = { 6000, 6000, 6000, 6000, 6000, 6000, 6000, 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 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, 400.0}
Dim RFHL(8) = {4000.0,4000.0,4000.0,4000.0,4000.0,4000.0,4000.0,4000.0}
Dim RFHY(8) = { 0.005, 0.005, 0.005, 0.005, 0.005, 0.005, 0.005, 0.005}
Dim RFOF(8) As Long = { 100, 100, 100, 100, 100, 100, 100, 100}