High-speed Data Acquisition System Research Articles

DEVELOPMENT OF THE TEST SYSTEM FOR MEASURING THE IMPACT ENERGY OF A HYDRAULIC BREAKER

A hydraulic breaker for construction machinery generally used for the destroying and disassembling of buildings, crashing road pavement, breaking rocks at quarry and so on. So the measurement of the impact energy of a hydraulic breaker is very important thing to prove its capability to manufacturers and customers. In this study, the test system for measuring the impact energy of a hydraulic breaker was designed and constructed. The test system was consisted with hydraulic cylinders for mounting a breaker, impact absorbing base and frames, pressure and flow sensors, high speed and accurate data acquisition system, diesel engine driven hydraulic power pack and etc. The test process of the developed system was carried by measuring guide for tool energy rating for hydraulic breakers which was developed by the CIMA (Construction Industry Manufacturers Association) USA. The developed test system can be applied to measure the impact energy for various kind of hydraulic breakers.

Automatic Data Acquisition System for Offshore Oil Pipeline Magnetic Flux Leakage On-line Inspection

In order to assure the safety of oil pipeline transmission, it is very important to continue routine inspection of offshore pipelines to identify defects or corrosions as early as possible. A high-speed inspection data acquisition system was developed for the magnetic flux leakage (MFL) method, with 12 bit sampling precision and 1.25 M/s sampling frequency. This system consists of a micro-computer, electronic memory, pre-processing circuit, power unit, digital signal processor (DSP), Field Programmable Gate Array (FPGA) and other components. The method adopts hardware and software cooperation to control data acquisition, filtering, encoding, handling, storage and transmission. The main function is MFL signal pre-processing, real-time data acquisition, de-noising and data compression. The basic characteristics of the system, design considerations, data filtering, data compression methods and experiment results are described. Experiments showed the system has a good performance.

A 10 GHz 4:1 MUX and 1:4 DEMUX implemented by a Gigahertz SiGe FPGA for fast ADC

This paper describes the implementation of a scalable SiGe FPGA that serves as an interleaving and deinterleaving block in a high-speed reconfigurable data acquisition system. In this paper, the di...

Pumping criterion and dynamic measurements of an inverted U-shape heat driven pump using microchannels and miniature check valves

We demonstrated an inverted U-shape heat driven pump consisting of a microchannel heat sink, two vertical branches and two miniature check valves. A new criterion, which is governed by the fluid physical properties, the geometry effect and the heat transfer rates at various oscillating stages, was developed. The theory can explain the operating range of the applied heating power. The dynamic measurements with a high speed data acquisition system shows that periodically a full cycle can be subdivided into a short liquid suction stage, a bulk boiling and a fluid discharge stage, followed by a pressure decrease stage with both of the valves closed. The average mass flow rate is small and can be computed by the energy conservation equation. The cycle period is shortened with increasing the applied heating power. The wall temperatures of the microchannel heat sink are oscillating with small amplitudes but they are slightly higher than the saturated temperature of the working fluid by several degrees. Deionized water was selected as the working fluid. Finally a closed loop heat driven pump design incorporating the microchannel heat sink and the condenser fin heat sink is proposed.

Frictional melting can terminate seismic slips: Experimental results of stick‐slips

The appropriate setting of sensors and the use of a high speed data acquisition system enabled us to detect the exact time of melting of the slip surfaces during a stick‐slip event (fault displacement of 0.32 mm, stress drop of 230 MPa, rise time of 23 μs and maximum slip velocity of 40 m/s) in triaxial apparatus at 150 MPa confining pressure. Once slip started, the friction coefficient decreased continuously from 0.55 to 0.3, after which the frictional resistance recovered promptly and remarkably. This strengthening can be attributed to the highly resistive initial melt, a potential mechanism for arresting seismic slips.

A 10 GHz 4:1 MUX and 1:4 DEMUX implemented by a Gigahertz SiGe FPGA for fast ADC

This paper describes the implementation of a scalable SiGe FPGA that serves as an interleaving and de-interleaving block in a high-speed reconfigurable data acquisition system. In this paper, the different generations of SiGe configurable blocks (Basic Cells(BC)) evolved from the Xilinx 6200 are presented and measured. The latest generation has a 94% reduction in power consumption (from 71 to 4.2mW) and an 82.5% reduction of the propagation delay (from 238 to 42ps) compared to the first generation design. To demonstrate the SiGe FPGA's capabilities of handling gigahertz signals, the SiGe FPGAs configured as the 4:1 multiplexer and 1:4 demultiplexer were designed to run at 10Gbps. The comparisons between the SiGe and CMOS FPGAs are also provided. With these design results, the SiGe FPGA is able to process gigahertz signals such as S and K microwave bands.

High-speed data acquisition and digital signal Processing system for PET imaging techniques applied to mammography

This paper is framed into the Positron Emission Mammography (PEM) project, whose aim is to develop an innovative gamma ray sensor for early breast cancer diagnosis. Currently, breast cancer is detected using low-energy X-ray screening. However, functional imaging techniques such as PET/FDG could be employed to detect breast cancer and track disease changes with greater sensitivity. Furthermore, a small and less expensive PET camera can be utilized minimizing main problems of whole body PET. To accomplish these objectives, we are developing a new gamma ray sensor based on a newly released photodetector. However, a dedicated PEM detector requires an adequate data acquisition (DAQ) and processing system. The characterization of gamma events needs a free-running analog-to-digital converter (ADC) with sampling rates of more than 50 Ms/s and must achieve event count rates up to 10 MHz. Moreover, comprehensive data processing must be carried out to obtain event parameters necessary for performing the image reconstruction. A new generation digital signal processor (DSP) has been used to comply with these requirements. This device enables us to manage the DAQ system at up to 80 Ms/s and to execute intensive calculi over the detector signals. This paper describes our designed DAQ and processing architecture whose main features are: very high-speed data conversion, multichannel synchronized acquisition with zero dead time, a digital triggering scheme, and high throughput of data with an extensive optimization of the signal processing algorithms.

Results of the Virgo central interferometer commissioning**Presented by F Bondu for the Virgo Collaboration.

The interferometric gravitational wave detector Virgo has successfully completed the first major step of its commissioning. It consists of a Michelson interferometer with 6 m arms with suspended mirrors. The interferometer is tuned to the dark fringe with a recycling mirror on the other port (bright fringe) to form an equivalent 12 m long Fabry–Perot cavity. This setup has allowed us to validate the major technology choices that have been made: passive seismic attenuators, a light source with a long mode cleaner, many analogue and digital servo loops, control software, high speed data acquisition system. A sensitivity of 8 × 10−17 m Hz−1/2 at 1 kHz together with a duty cycle of 80% has been attained during a 72 h engineering run. The data analysis allowed us to understand the noise contributions, and several improvements have been carried out while proceeding with the end of the installation of vacuum tubes and the remaining suspensions, and before starting the commissioning of the 3 km long Fabry–Perot cavities.

Radioactive source calibration technique for the CMS hadron calorimeter

Relative calibration of the scintillator tiles used in the hadronic calorimeter for the Compact Muon Solenoid detector at the CERN Large Hadron Collider is established and maintained using a radioactive source technique. A movable source can be positioned remotely to illuminate each scintillator tile individually, and the resulting photo-detector current is measured to provide the relative calibration. The unique measurement technique described here makes use of the normal high-speed data acquisition system required for signal digitization at the 40 MHz collider frequency. The data paths for collider measurements and source measurements are then identical, and systematic uncertainties associated with having different signal paths are avoided. In this high-speed mode, the source signal is observed as a Poisson photo-electron distribution with a mean that is smaller than the width of the electronics noise (pedestal) distribution. We report demonstration of the technique using prototype electronics for the complete readout chain and show the typical response observed with a 144 channel test beam system. The electronics noise has a root-mean-square of 1.6 least counts, and a 1 mCi source produces a shift of the mean value of 0.1 least counts. Because of the speed of the data acquisition system, this shift can be measured to a statistical precision better than a fraction of a percent on a millisecond time scale. The result is reproducible to better than 2% over a time scale of 1 month.

Testing the dynamics of shutdown systems instrumentation in reactor trip measurements

Periodic testing of the dynamics of the shutdown systems and their instrumentation is performed in the CANDU nuclear power plants of Ontario Power Generation (OPG) and Bruce Power. Measurements of in-core flux detector (ICFD) and ion chamber (I/C) signals responding to the insertion of shut-off rods (shutdown system No. 1, SDS1), or to the injection of neutron absorbing poison (shutdown system No.2, SDS2) are regularly carried out at the beginning of planned outages. A reactor trip is manually initiated at high power and the trip response signals of ICFDs and I/Cs are recorded by multi-channel high-speed high-resolution data acquisition systems set up temporarily at various locations in the station. The sampling of the seaprate data acquisition systems are synchronized through the headset communication systems of the station. A total of 120 station signals can be sampled simultaneously up to 2500 samples per second. The effective prompt fractions of the ICFDs are estimated from the measured trip response. Effectiveness and the timeline of the trip mechanism are assessed in the measurement as well. The measurement can identify ICFDs with abnormally slow response (under-prompt) or overshooting response (over-prompt) at the beginning of the outage. The time required for the signals to drop to predefined fractions of their pre-trip values (level crossing time) is plotted as a function of detector position and compared against safety requirements. The propagating effect of shut-off rod insertion or poison injection on the flux is monitored by the level crossing times of ICFDs and ion chambers.

Ignition and boost effects on large-bore engine in-cylinder heat transfer

One cylinder of the Colorado State University large-bore test engine was instrumented with fast-response surface thermocouples for heat-transfer analysis. Probes were installed at several locations progressively farther from the ignition source and their outputs were recorded along with combustion pressure using a high-speed data-acquisition system. The engine was operated with two different ignition methods and the manifold boost pressure and cylinder jacket water temperature (JWT) were varied. The recorded surface temperature data were processed to calculate in-cylinder heat transfer. Combustion initiated with a screw-in type pre-combustion chamber resulted in significantly different characteristics than that initiated by a conventional spark plug. The differences in peak heat-flux value could likely be attributed to flame quench distance. Differences in other portions of the cycle could have been caused by significantly increased flame velocities associated with the pre-chamber jet. Increasing boost pressure from 25 to 54 kPa decreased peak heat-flux values about 20–30% and steady-state values about 13%. Increasing JWT 14 K had an insignificant effect on heat flux and combustion pressure.

METSO TO CUT UK MANUFACTURING CAPACITY

Compressive crushing has been proven to be one of the most energy efficient principles for breaking rock particles (Schönert, 1979). In this paper the cone crusher, which utilizes this mechanism, is investigated using the discrete element method (DEM) and industrial scale experiments. The purpose of the work is to develop a virtual simulation environment that can be used to gain fundamental understanding regarding internal processes and operational responses. A virtual crushing platform can not only be used for understanding but also for development of new crushers and for optimisation purposes.Rock particles are modelled using the bonded particle model (BPM) and laboratory single particle breakage tests have been used for calibration. The industrial scale experiments have been conducted on a Svedala H6000 cone crusher operated as a secondary crushing stage. Two different close side settings have been included in the analysis and a high speed data acquisition system has been developed and used to sample control signals such as pressure and power draw in order to enable detailed comparison with simulation results. The crusher has been simulated as a quarter section with a batch of breakable feed particles large enough to achieve a short moment of steady state operation. Novel methods have been developed to estimate the product particle size distribution using cluster size image analysis. The results show a relatively good correspondence between simulated and experimental data, however further work would be need to identify and target the sources of observed variation and discrepancy between the experiments and simulations.

Laboratory research facility for testing hydrodynamic thrust bearings

A research facility has been designed and manufactured to study performance characteristics of industrial hydrodynamic thrust bearings. The facility includes a test rig containing two identical tilting pad thrust bearings operating against separate collars. A shaft supported by two journal bearings is driven by a 143kW variable-speed d.c. motor. The bearings are tested in a balanced pair to accommodate the substantial axial force generated by hydraulic cylinders. Bearing instrumentation encompasses a distribution of thermocouples, pressure transducers and oil-film thickness sensors of eddy current type. Two piezoelectric transducers for pressure profile measurements and three thermistors are mounted in one of the shaft collars. Additional instrumentation includes thermocouples, pressure sensors, flowmeters, a load cell and inductive sensors. Signals from all sensors are logged by a personal computer-based high-speed data acquisition system that acquires the measured data, conditions them and presents the results on line. Power losses are obtained by monitoring bearing friction torque and by the calorimetric technique. A detailed description of the research facility is provided together with some representative results of equalizing tilting pad thrust bearing performance obtained for the steady state and transient operating conditions.

Event building in an intelligent network interface card for the LHCb DAQ system

LHCb is an experiment being constructed at CERN's Large Hadron Collider accelerator for the purpose of studying precisely the charge and parity violation parameters in the B-B meson system. Triggering poses special problems since the interesting events containing B-mesons are immersed in a large background of inelastic p-p reactions. Therefore, a four-level triggering scheme (Level-0 to Level-3) has been implemented. Full event building is performed between Level-1 and Level-2. Powerful embedded processors, used in modern intelligent network interface cards, are attractive to use to handle the event-building protocol in the high-speed data-acquisition system. The implementation of an event-building algorithm developed for a specific gigabit Ethernet network interface controller is presented, and results from performance measurements are discussed.

Assessing metal transfer stability and spatter severity in flux cored arc welding

Five experimental basic type flux cored arc welding consumable wire electrodes were manufactured from the same base formulation. The composition of these electrodes was adjusted in an attempt to improve the operating performance. This involved additions of various ratios of alkali oxides, namely, lithium, magnesium, sodium, and potassium containing ingredients, in the flux formulations. The operating behaviours of these experimental electrodes and two reference products (i.e. one commercial basic T–5 and one commercial rutile T–1 electrode) were thoroughly investigated by recording welding arc signals using a high speed data acquisition system. By comparing these electrodes among themselves, the experimental electrodes were reported to exhibit extremely stable arcs, some showing electrical arc signals even smoother than those for the reference rutile grade electrode. Despite their improved metal transfer consistency, however, basic electrodes were characterised by somewhat higher spatter levels.

Design and performance of a data acquisition system for VUB-PET

A flexible and high-speed VME-based data acquisition system (DAQ) has been designed to process data from the University of Brussels (VUB) small-animal positron emission tomography (PET) system. The core tasks of the system are performed by two custom VME modules: a trigger module and a fast readout module (FRO). Following the detection of a valid coincidence event by the trigger unit, the raw data from all analog-to-digital converter channels involved are read out simultaneously via a FRO. An onboard digital signal processor (DSP) processor checks and calibrates these data. To increase the transfer throughput of the list mode data to a SUN Ultra Sparc 1 workstation, the DSP processor compresses the data format to a 6-byte data packet per event. The maximum average sustained acquisition rate of the system is 200000 counts per second (cps), while peak rates up to 2 Mcps can be handled. The DAQ also provides online measurement of the random event rate, the single event rate and event losses due to electronic dead time.

Measurement of bubble size distribution in protein foam fractionation column using capillary probe with photoelectric sensors.

Bubble size is a key variable for predicting the ability to separate and concentrate proteins in a foam fractionation process. It is used to characterize not only the bubble-specific interfacial area but also coalescence of bubbles in the foam phase. This article describes the development of a photoelectric method for measuring the bubble size distribution in both bubble and foam columns for concentrating proteins. The method uses a vacuum to withdraw a stream of gas-liquid dispersion from the bubble or foam column through a capillary tube with a funnel-shaped inlet. The resulting sample bubble cylinders are detected, and their lengths are calculated by using two pairs of infrared photoelectric sensors that are connected with a high-speed data acquisition system controlled by a microcomputer. The bubble size distributions in the bubble column 12 and 1 cm below the interface and in the foam phase 1 cm above the interface are obtained in a continuous foam fractionation process for concentrating ovalbumin. The effects of certain operating conditions such as the feed protein concentration, superficial gas velocity, liquid flow rate, and solution pH are investigated. The results may prove to be helpful in understanding the mechanisms controlling the foam fractionation of proteins.

Laser-based measurement of liquid temperature or concentration at a solid–liquid interface

Abstract This work presents a real-time, non-contact, laser-based thermoreflectance technique to measure changes in temperature or concentration of stationary or flowing liquids at a transparent solid–liquid interface, e.g., a glass window. Variations in temperature or concentration result in a change in refractive indices of the liquid, which, in turn, alter the reflectivity at the interface. A 3 mW semiconductor laser diode serves as the light source, and a silicon photodiode monitors the intensity variations of the reflected laser beam. The temperature of three liquids, water, ethanol, and 1-propanol, are measured with very good agreement found between the laser technique and a calibrated thermistor. The concentration of a methanol–propanol solution is successfully measured as well. The maximum uncertainty is 0.6°C for the temperature measurement and 0.2% for the concentration measurement, respectively. The presented experimental configuration is simple, inexpensive and reliable. Additionally very high spatial and temporal resolution are possible: the beam spot size can be readily reduced to ∼20 μm or less, and a temporal resolution of ∼1 μs or less can be achieved with a high-speed data acquisition system. Thus, temperature or concentration changes in a flowing liquid in small-scale devices such as microelectro-mechanical-systems (MEMS) and microfluidic structures, and the systems with fast temporal variation, e.g., rapid solidification and fast mixing, can be effectively measured.

High-speed multi-input VME bus data acquisition system

A data acquisition module, developed under a modularorganizational architecture with links to an object-oriented designapproach, is described. The module comprises four independent 250 MHzeight-bit data acquisition channels and a DSP, each channel controlling alarge memory pool for converted data and supporting several trigger andoperating mechanisms. The hardware, although complex, is completelycontrolled through a set of hierarchically organized classes, making use ofthe object-oriented programming paradigm to keep complexity (from theuser's and programmer's points of view) to a minimum.The integration of the module in the data acquisition system of thereflectometry diagnostic in tokamak ASDEX-Upgrade is described, showing thehardware in regular use and the validity of the object-oriented interfacedeveloped for programming.

High-speed data acquisition system for spectroscopic imaging of ionizing particles

The aim of this paper is to describe a very general readout system for one-dimensional ionizing particle detectors. This system is based on a VME (Versa Module Eurocard, IEEE P1014, Mar. 12, 1987) bus which allows us to read and store up to 1000 channels in 1 ms. Thus, two-dimensional images can be recorded in a short time, for example by moving the measurement device composed of the detectors and their onboard electronics. This concept has been applied to a new low-dose X-ray radiology apparatus. A direct numerical radiographic image obtained with this system is presented.