Strain Measurement Instrumentation:

Many commercial and experimental transducers utilise resistance wire strain gauges to measure the small changes in physical form that result from the application of physical loading.  Transducers for the measurement of pressure, tensile, rotational and compressive force, angular displacement and acceleration are all commercially available and the field measurement environment demands portable readout systems that retain the accuracy of laboratory instruments with practical operator features.

CADEANCO manufactures a range of readout devices for both single and multi-channel applications to cover all of the basic measurement configurations of resistance wire strain gauge circuits.  All of these readouts employ the same proven design components and our designs can be adapted  to accommodate unusual or experimental measurement applications.

The collection of data has become a science in its own right and there are many commercial data logging systems for the myriad of sensors available.  CADEANCO and its network partners have over 25 years of practical experience in the design, manufacture and application of data acquisition systems, many designed for unique or unusual applications in the mining and geotechnical field.  These include IP67 Systems for both submerged and buried installations as well as OEM Systems that are intrinsically safe and approved for use in petroleum and coal mining applications.

By combining our field experience and design techniques, we can generate a solution to almost any data acquisition problem and then complete the design cycle by producing an integrated hardware and software package tailored to your specific requirements.

A great number of laboratory testing applications require the determination of the properties of samples taken in the field for both investigative and quality assurance purposes.  CADEANCO has designed and manufactured measurement systems to determine the strength of rock core samples and incorporation of microprocessor technology into these systems greatly reduces operator workload for recording of sample data.  The integration of the measurement system with personal computers ensures the integrity of test data which is available for processing immediately without having to be copied into spreadsheet applications.

Measurement of in-situ loads, especially roof loads of underground excavations such as mines and tunnels, has been made easier through the development of strain gauge load cells.  CADEANCO can supply two basic cells to suit both conventional roof bolt (26mm ID) and high strength cable strand bolts (17mm ID) load measurement applications.  These cells are manufactured using NC machining techniques which produces a repeatable loading performance curve.  Each cell has a matched spherical-seat washer to remove asymmetrical loading and give a true indication of axial load on the tension member.  Both cells share a common physical specification and can be read using either the multi-channel IS2000 readout with FBC Interface or the single channel LCM1 readout.

The measurement of sample displacement under varying load conditions is a basic requirement of many laboratory test procedures.   CADEANCO can design, manufacture and install custom displacement measurement sensors using a variety of transducers to suit most specifications.  We are also able to integrate sensors with signal conditioning systems to provide a convenient manual or automatic data presentation interface.

The rapid development of microprocessor technology over the last six years has given these tiny components much of the processing power of full desktop personal computers of only a few years ago.  CADEANCO and its alliance partners have been utilising these advances to develop systems that carry out their measurements as close to the point of application as possible, thus reducing errors in the measurement process and recording data without the need for operator intervention.  Such systems are able to record data in a reliable and repetitive manner, ensuring that variances due to the operator are minimised.  This capability has provided data trends on background parameters such as tidal influences to be monitored and corrections to target data to be made for more precise results, a task impossible to perform with manual data monitoring.

Although automated data logging systems have been employed for many years, this new generation of systems allows the measurement to be calibrated over its range for a corrected data output directly in engineering units.   This technique can be utilised for local display of data on multi-line alphanumeric displays which can also provide  preferred output dimensions, simple instructions, warning signs and on-line help to the operator.

The microprocessor also allows instruments to be run by remote control from a personal computer connected via an RS232 or RS485 serial interface.  This active interface enables data to be recorded directly to data files, included into existing databases or appended to screen charts if required.  In addition to dispensing with manual recording of output data, the remote control facility ensures operator safety during hazardous sample testing.

Many laboratories employ instrumentation systems housed in 19" rack-mount modules that enable complete systems to be moved around the sample testing area as required.

CADEANCO has developed a selection of electronic sub-systems that can be readily housed in rack-mount cases to create custom instrumentation solutions for almost any particular need.  We can design the layout of front and rear panel components to your specification and oversee all aspects of the design including mechanical drafting, panel metalwork, custom screen-printing and integration of the rack components into the existing testing environment.

Modules manufactured for customers have included power supplies, stepping motor controllers, signal patch panel boards, temperature controllers and communications interfaces as well as signal conditioning modules for displacement transducers, pressure transducers, LVDT transducers, DCDT transducers and strain gauge circuits.

CADEANCO uses LabVIEW Virtual Interface software supplied by National Instruments exclusively for the design of Windows software used to communicate with its intelligent instrument devices.  This state-of -the-art software has all of the features required to design an instrumentation system within the computer, communicating to the testing environment through the existing serial interfaces or via proprietary interface cards available from National Instruments.  All controls and indicators are available to the operator on the monitor display and control outputs can be changed by dragging the displayed knobs and dials to the required values with the computer mouse.

The Virtual Interface (VI) allows instrumentation systems to have an unlimited life as software can be amended or extended to include new features as required.  Similarly, operator safety can be enhanced by astute design of the interface to prevent hazardous sequences of events to occur, while operator error is greatly diminished by removing access to unimportant or distracting panel functions at critical phases of the test process.  When combined with the versatility of microprocessor controlled testing hardware, the LabVIEW Interface makes possible additional features such as password protection to selected system functions, high speed data recovery and remote access via landline, radio and GSM telemetry.

CADEANCO is a member of the National Instruments User Group and we would be pleased to discuss the application of Virtual Instrumentation to your particular instrumentation problem.

In August 1996, CADEANCO and its alliance partners were approached by the Airport Authority Hong Kong to design an automatic instrumentation system to monitor settlement measurement devices installed in the reclaimed landfill material forming the expanded island of Chek Lap Kok.  This man-made island of 1248 hectares was created to carry the new Hong Kong International Airport (HKIA) and was the largest civil engineering project ever proposed to that time.  By November 1996, construction of the platform was complete and a prototype of the Automatic Magnetic Extensometer Controller (AMEC) system to monitor both magnetic extensometers and vibrating wire piezometers was presented to the Geotechnical Engineering Section for their approval.  The design of the platform was the first of its kind and there will continue to be considerable interest in its performance for the first five to ten years of its operational life.  Instruments were installed in clusters at twenty-five selected sites across the platform and these were read manually during the construction phase of the project.  Once the airport infrastructure began to take shape however, access to these sites became more difficult and will be severely restricted once aircraft are using the facility.

After presentations and discussion with a number of Hong Kong based instrument companies, approval for the system was finally granted and the first instrument was installed in April 1998, continuing in stages for the next three months.  The specification called for battery powered instrumentation that could operate unattended for extended periods of time, submerged in up to 2m of water.  The original design was amended after an evaluation of the initial data and continues to provide high quality data that will contribute to the evaluation of design parameters for future reclamation projects throughout the world.