Data Acquisition Board Research Articles

Design of a Magnetic Induction Tomography System by Gradiometer Coils for Conductive Fluid Imaging

Magnetic induction tomography (MIT) is a non-intrusive and non-invasive method that can image the cross-sectional conductivity distribution inside the object without contact. Target applications are conductive fluid testing in biomedical or industrial processes. The gradiometer coil is used as the front-end sensor of the proposed MIT system. As demonstrated through theoretical analysis and numerical simulation, the phase sensitivity to the conductivity of the gradiometer is greatly enhanced by eliminating the primary voltage with differential coils. The sensitivity is tunable by the residual voltage. The experimental test illustrates that 2 °/(Sm -1 ) sensitivity can be achieved at 10 MHz. The eight-channel MIT system MIT hardware is based on a dual-channel data acquisition board PCI-5122 at 100-MS/S sample rate per channel and a waveform generator PCI-5412 as the 10-MHz excitation source. One frame of data contains 64 phase measurements, and each is calculated with the built-in fast Fourier transform (FFT) function on LabVIEW. With full-period sampling and averaging, the sensor array can achieve less than 5-m° phase noise. The system yields good long-term stability with a phase drift less than 20 m° over 4 h. We use a FEM model to solve the forward problem and then reconstruct the 2D images by a one-step Laplacian regularization algorithm. The experimental phantom tests show that the system is capable of imaging the conductivity distribution and also indicate that the images' quality becomes better by tuning an appropriate regularization coefficient.

A Hardware Implemented Autocorrelation Technique for Estimating Power Spectral Density for Processing Signals from a Doppler Wind Lidar System.

A signal processing technique utilizing autocorrelation of backscattered signals was designed and implemented in a 1.5 µm all-fiber wind sensing Coherent Doppler Lidar (CDL) system to preprocess atmospheric signals. The signal processing algorithm’s design and implementation are presented. The system employs a 20 kHz pulse repetition frequency (PRF) transmitter and samples the return signals at 400 MHz. The logic design of the autocorrelation algorithm was developed and programmed into a field programmable gate array (FPGA) located on a data acquisition board. The design generates and accumulates real time correlograms representing average autocorrelations of the Doppler shifted echo from a series of adjustable range gates. Accumulated correlograms are streamed to a host computer for subsequent processing to yield a line of sight wind velocity. Wind velocity estimates can be obtained under nominal aerosol loading and nominal atmospheric turbulence conditions for ranges up to 3 km.

Adjustable Method for Real-Time Gait Pattern Detection Based on Ground Reaction Forces Using Force Sensitive Resistors and Statistical Analysis of Constant False Alarm Rate

A new approach is proposed to detect the real-time gait patterns adaptively through measuring the ground contact forces (GCFs) by force sensitive resistors (FSRs). Published threshold-based methods detect the gait patterns by means of setting a fixed threshold to divide the GCFs into on-ground and off-ground statuses. However, the threshold-based methods in the literature are neither an adaptive nor a real-time approach. To overcome these drawbacks, this study utilized the constant false alarm rate (CFAR) to analyze the characteristics of GCF signals. Specifically, a sliding window detector is built to record the lasting time of the curvature of the GCF signals and one complete gait cycle could be divided into three areas, such as continuous ascending area, continuous descending area and unstable area. Then, the GCF values in the unstable area are used to compute a threshold through the CFAR. Finally, the new gait pattern detection rules are proposed which include the results of the sliding window detector and the division results through the computed threshold. To verify this idea, a data acquisition board is designed to collect the GCF data from able-bodied subjects. Meanwhile, in order to test the reliability of the proposed method, five threshold-based methods in the literature are introduced as reference methods and the reliability is validated by comparing the detection results of the proposed method with those of the reference methods. Experimental results indicated that the proposed method could be used for real-time gait pattern detection, detect the gait patterns adaptively and obtain high reliabilities compared with the reference methods.

FPGA-Based Interface of Digital DAQ System for Double-Scattering Compton Camera.

The double-scattering Compton camera (DSCC) is a radiation imaging system that can provide both unknown source energy spectra and 3D spatial source distributions. The energies and detection locations measured in coincidence with three CdZnTe (CZT) detectors contribute to reconstructing emission energies and a spatial image based on conical surface integrals. In this study, we developed a digital data acquisition (DAQ) board to support our research into coincidence detection in the DSCC. The main components of the digital DAQ board were 12 ADCs and one field programmable gate array (FPGA). The ADCs digitized the analog 96-channel CZT signals at a sampling rate of 50MHz and transferred the serialized ADC samples and the bit and frame clocks to the FPGA. In order to correctly capture the ADC sample bits in the FPGA, we conducted individual sync calibrations for all the ADC channels to align the bit and frame clocks to the right positions of the ADC sample bits. The FPGA logic design was composed of IDELAY and IDDR components, six shift registers, and bit slip buffer resources. Using a Deskew test pattern, the delay value of the IDELAY component was determined to align the bit clock to the center of each sample bit. We determined the bit slip in the 12-bit ADC sample using an MSB test pattern by checking where the MSB value of one is located in the captured parallel data. After sync calibration, we tested the interface between the ADCs and the FPGA with a synthetic analog Gaussian signal. The 96 ADC channels yielded a mean R 2 goodness-of-fit value of 0.95 between the Gaussian curve and the captured 12-bit parallel data.

Tribometric Device for Determining Friction Forces and Friction Coefficients in the Case of Dry Friction of Materials

Abstract The aim of the paper was to develop a device (“pin-on-disc” type) for the measurement of friction in plane friction couplings with sliding movement. On tribometric device (made in our laboratory) we can measure the friction force, friction coefficient and wear, for different loading conditions, speeds, time and material coupling. For the measurement of the frictional force as well as of the coefficients of friction, mainly the method with a resistive tensiometric transducer is used. With a DataQ DI 245 data acquisition board it is possible to record up to 2 kHz frequencies in the range of -10 ÷ +10 mV with a resolution of 13 bits. To test the functionality of the device, a preliminary test was carried out for a steel pin- on- cast iron disc, for different values of the normal pushing force. The device was calibrated and the measurement results were recorded and processed on the computer.

Development of high-precision distributed wireless microseismic acquisition stations

Abstract. In recent years, owing to the shortage of oil and gas resources and increasing difficulty in mining, traditional (wired) microseismic monitoring equipment has been unable to meet the needs of energy exploitation. Therefore, it is necessary to develop new high-precision seismic exploration and data acquisition systems. In this study, we combined advanced acquisition systems with wireless technology to develop a new wireless microseismic acquisition system. The hardware circuit of the acquisition system mainly includes a data acquisition board and a main control board. High-precision analog-to-digital conversion and digital filtering technologies are used to provide data with high signal-to-noise ratios, resolution, and fidelity to the acquisition stations. Key technologies were integrated into the ARM (Advanced RISC Machines) of the main control board: reliable GPS technology was employed to realize synchronous acquisitions among various acquisition stations, and WIFI technology was used to achieve wireless data communication between acquisition stations and the central station, thus improving the data transmission speed and accuracy. After conducting a series of evaluation tests, it was found that the system was stable, convenient to use, and had high data accuracy, therefore providing significant support for the solution to problems encountered in current oil and gas exploration processes, such as the complicated environment and inconvenient construction.

Monitoring the Chloride Concentration in International Scheldt River Basin District Water Using a Low-Cost Multifunction Data Acquisition Board

In analytical chemistry laboratories, to gather in the shortest time as many data as possible with the utmost accuracy and precision, high throughput automated setups are indispensable. In the present study, to determine the chloride concentration in the international Scheldt river basin district, experiments are carried out utilizing a thermostatically controlled semi-automated setup. A novel ICT-based method is developed using a low-cost multifunction Data Acquisition Board (DAQ) controlled by a homebuilt LabVIEW™ program. Specifically, this approach enables a correlation between different parameters i.e., droplet volume, temperature, A/D voltage conversions. Here, processing experimental data of a potentiometric precipitation titration utilizing a silver nitrate standard solution as titrant in a manual burette equipped with a controllable electronic valve allows for a preliminary indication of the titration end point via the Virtual Instrument (VI) numerical first derivative tool in the LabVIEW software. The LabVIEW tool is compared with the well-known Gran method implemented in the LabVIEW program, emphasizing an accurate performance of the setup to determine the chloride concentration in fresh river water. We are confident that our findings are evidence of the versatile and powerful features of the LabVIEW controlled DAQ in the analytical chemistry laboratory.

An integrated IoT-Wi-Fi board for remote data acquisition and sharing from innovative immunosensors. Case of study: Diagnosis of celiac disease

A new compact diagnostic device exploiting the integration of screen printed electrode-based immunosensors and remote-controlled IoT-WiFi acquisition board has been realized and validated for diagnosis of Celiac Disease as case of study. The immunodevice is based on chemisorption of open tissue transglutaminase enzyme on the surface of gold nanoparticles-functionalized carbon screen printed electrodes. IgA and IgG anti-tissue transglutaminase target antibodies are recognized by the immobilized bioreceptor as highly specific biomarkers related to Celiac Disease. The signal from the amperometric sensor is acquired and processed through on-purpose developed IoT-WiFi integrated board, allowing for real-time data sharing on cloud services to directly notify all users (physicians, caregivers, etc.) on device outcome. The proposed solution does not require customized hardware or software.The analytical performances of the immunosensors were optimized by experimental design, obtaining diagnostically useful limit of detection (LOD) and limit of quantitation (LOQ) values (LODIgA = 3.2 AU mL−1; LODIgG = 1.4 AU mL−1; LOQIgA = 4.6 AU mL−1; LOQIgG = 2.3 AU mL−1) as well as good intermediate precision (RSD < 5%).The high discrimination capability of the IoT-Wi-Fi device between positive and negative serum control resulted to be suitable for diagnostic purposes, with outstanding statistical significance (p < 0,001)

Portable exhaled breath analyzer employing fluctuation-enhanced gas sensing method in resistive gas sensors

This paper presents a portable exhaled breath analyser, developed to detect selected diseases. The set-up employs resistive gas sensors: commercial MEMS sensors and prototype gas sensors made of WO3 gas sensing layers doped with various metal ingredients. The set-up can modulate the gas sensors by applying UV light to induce physical changes of the gas sensing layers. The sensors are placed in a tiny gas chamber of a volume of about 22 ml. Breath samples can be either injected or blown into the gas chamber when an additional pump is used to select the last breath phase. DC resistance and resistance fluctuations of selected sensors using separate channels are recorded by an external data acquisition board. Low-noise amplifiers with a selected gain were used together with a necessary bias circuit. The set-up monitors other atmospheric parameters interacting with the responses of resistive gas sensors (humidity, temperature, atmospheric pressure). The recorded data may be further analysed to determine optimal detection methods.

Influence of Hygroscopic expansion on cuspal deflection of tooth composite restoration (an in vitro study)

Purpose: This study evaluates the effect of hygroscopic expansion on the cusp deflection of tooth composite restoration. Materials and Methods: Eighty (80) human premolars extracted for orthodontic reasons stored in normal saline were used. Large Mesiooccluso distal cavity (MOD) cavity was prepared. The specimens were divided into two main groups (40 each). each main group divided into two groupsaccording to bonding used (G-bond & composite consensual adhesive) each group (20 each), subdivided into four equal subgroups as follows: group A: Using low shrinkable resin composite (Filtek™ P90 Silorane shade A2; 3M ESPE,St Paul, MN, USA) with its adhesive system. group B: Using low shrinkable composite (Filtek P90 Silorane shade A2; 3M ESPE) with Gbond (GC, Tokyo, Japan). group C: Using Filtek™ Z350 (3M ESPE) composite with Gbond (GC). group D: Using Filtek Z350 (3M ESPE) composite with Adhe SE (Ivoclar Vivadent , Schaan, Liechtenstein). Specimens were stored in water for four time interval (immediate, 1, 2, 4&12) weeks. Each group was further divided into equal subgroup (5 teeth per each) according to immersion in normal saline. Cuspal deflection was detected by Universal measuring microscope (Carl Zeiss, Jena, Germany) and Universal horizontal metroscope (Universal Langenmesser; Carl Zeiss). The buccal and lingual cusp movements were recorded for 2000 s and the measured value (as a function of time) was stored on a computer through a data acquisition board. The buccal and lingual cusp movements were recorded again after the specimens were immersed in deionized water. The results were statistically analyzed using ANOVA followed by Student–Newman–Keuls post hoc tests. Results: The cavities which restored with the silorane (P90) resin-based composites recorded less cuspal deflection than the methacrylate-based (Filtek Z350) group the cavities which restored with silorane (P90) resin-based composites and bonded with its consensual adhesive recoreded the least cuspal deformations. cuspal deformation of the restored teeth gradually decreased, reversing the shrinkage deformation. The two hydrophobic resin composite restored teeth showed a gradual decrease of the shrinkage deformation due to hygroscopic expantion. Conclusion: Polymerization shrinkage deformationwas compensated by hygroscopic expansion within 4 weeks in teeth restored with a hydrophobic resin composite, while a hydrophilic restorative over-compensated polymerization shrinkage within 1 week causing tooth expansion.

Разработка программного компонента трассоискателя на базе устройства сбора данных Л КАРД E502

Разработка программного компонента трассоискателя на базе устройства сбора данных Л КАРД E502

Characterization of Respiratory Conditions Using Labview and Digital Spirometer

&lt;p&gt;One of the effective ways to diagnose various respiratory diseases is using spirometry test. Good spirometer comes with excellent graphical user interface. Spirometer is used to measure lung parameters such as Forced Expiratory Volume in the first second and the sixth seconds (FEV1 and FEV6). This paper presents an algorithm with Graphical User Interface (GUI) for characterization of respiratory conditions using LabVIEW Software. The whole spirometry system consists of a breathing circuitry with pressure sensor and a data acquisition board (NI sbRIO FPGA board). Results obtained from three different volunteers with different health performances are also presented in this paper. The FEV1/FEV6 ratio of a healthy volunteer is 81.1%, an asthma volunteer is 72.04%, and suspected bronchitis volunteer is 33.4%. Based on these results, the unhealthy volunteers tend to have smaller value of FEV1 with lower area under the curve when compared to healthy volunteer.&lt;/p&gt;

Bond graph modelling of a 4-parameter photovoltaic array

ABSTRACTA new model for simulating photovoltaic (PV) systems is presented. Bond Graph modelling is used as a basis technique. The proposed model allows prediction of generated energy under nonstandard conditions of temperature and irradiance. The proposed model is based on a 4-parameters model of the equivalent circuit of one diode. The proposed model has the property of being able to simulate the behaviour of a given PV module based only on information provided in the manufacturer datasheet. The proposed model also allows studying the effect of partial shading. As an advantage over other existing models of PV systems, the proposed model presents an extensive interconnection capacity. This feature allows simultaneous simulation with other subsystems to study the overall operation. For purposes of experimental validation of the proposed model, the construction of a tracer based on MOSFET that acts as a variable load is performed. The hardware control and reading of the curves are made using a data acquisition board.

A LabVIEW-based real-time acquisition system for crack detection in conductive materials

Large number of measurement techniques involves the scanning of a probe, while a physical quantity is measured. Data acquisition therefore requires high acquisition rates, together with an accurate synchronization between the probe control and the measurement. LabVIEW-based graphical programming language provides the flexibility of integration of data acquisition software/hardware for automated test and measurement applications using National Instruments (NI) high-speed data acquisition boards. This paper describes a new LabVIEW-Based automatic test system that can be used for eddy current testing (ECT) tests and measurements. The system deals with a pancake type coil, placed above a flat conductive plate with a crack. In order to achieve the crack detection, the probe scans the target and signals are collected by a NI data acquisition board. The software of the system has been developed using LabVIEW in order to realize the real time data acquisition of coil’s impedance. To verify the experimental results, simulations were performed using 3D finite element method. The system designed can be used for both education and specific research purposes.

The Squirrel-Cage Induction Motor Model and Its Parameter Identification Via Steady and Dynamic Tests

One of the most important bases for designing robust closed-loop controllers applied to induction motor with high performance is establishing its mathematical model and state observers, as well as the parameter identification with high accuracy. In this paper, a step-by-step mathematical model of the squirrel-cage induction motor is described at αβ coordinate frame where the parameters are defined in detailed form; the rotor flux linkages and load torque are estimated via an asymptotic observer; the induction motor parameter identification is performed via a data acquisition board, applying dynamic and steady-state tests. Inductances of the induction motor model are calculated using the proposed relationships between the magnetically coupled circuit and equivalent circuit model. The mathematical model, state observers, and parameter identification procedure of squirrel-cage induction motor are validated via comparison of simulation signals with their corresponding real-time signals. This validation is made experimentally by a steady-state test, where load conditions are changed via a dynamometer which is belt coupled with the squirrel-cage induction motor.

Experimental industrial signal acquisition board in a large scientific device

In order to measure the industrial signal of neutrino experiment, a set of general-purpose industrial data acquisition board has been designed. It includes the function of switch signal input and output, and the function of analog signal input. The main components are signal isolation amplifier and filter circuit, ADC circuit, microcomputer systems and isolated communication interface circuit. Through the practical experiments, it shows that the system is flexible, reliable, convenient and economical, and the system has characters of high definition and strong anti-interference ability. Thus, the system fully meets the design requirements.

Use of capacitive sensors with the instantaneous profile method to determine hydraulic conductivity

Due to the need to monitor soil water tension continuously, the instantaneous profile method is considered laborious, requiring a lot of time, and especially manpower, to set up and maintain. The aim of this work was to evaluate the possibility of using capacitive sensors in place of tensiometers with the instantaneous profile method in an area of the Lower Acarau Irrigated Perimeter. The experiment was carried out in a Eutrophic Red-Yellow Argisol. The sensors were installed 15, 30, 45 and 60 cm from the surface, and powered by photovoltaic panels, using a power manager to charge the battery and to supply power at night. Records from the capacitive sensors were collected every five minutes and stored on a data acquisition board. With the simultaneous measurement of soil moisture obtained by the sensors, and the total soil water potential from the soil water retention curve, it was possible to determine the hydraulic conductivity as a function of the volumetric water content for each period using the Richards equation. At the end of the experiment, the advantage of using capacitive sensors with the instantaneous profile method was confirmed as an alternative to using a tensiometer. The main advantages of using capacitive sensors were to make the method less laborious and to allow moisture readings at higher tensions in soils of a sandy texture.

Detecting Signals With Direct Fast Fourier Transform for Microarray Data Collection

Small signals are routinely detected at a frequency away from the 1/f noise. Typically, the signal source is modulated at a suitable frequency, and the harmonics of the modulation frequency in the signal are analyzed with phase sensitive detectors such as Lock-in amplifiers. Yet, the high cost and poor portability of stand-alone Lock-in amplifiers are obstacles to making such an approach of harmonic detection into a widely usable instrumentation. In this letter, we show that for many applications where signals are not too small (e.g., more than tens of micro-volts) the direct fast Fourier transform using a commercially available, general-purpose data acquisition board serves as a cost-effective alternative to Lock-in amplifiers without sacrificing the signal-to-noise ratio.

Human Sweat Analysis Using a Portable Device Based on a Screen‐printed Electrolyte Sensor

AbstractAnalysis of ammonium in human sweat during physical strain using a portable sensor device and enzymatic measurements are compared. The portable device is based on a screen‐printed electrolyte sensor connected with an evaluation board for data acquisition and transfer. During performance tests with artificial sweat, the sensor shows a low detection limit of 0.3 mM. Thus, the typical concentration range of ammonium in sweat lies within the working range of the sensor. We also demonstrate the necessity of the comparison measurement for verification of the correct performance of screen‐printed sensors and show how other components of human sweat influence the measured potential. Regarding the change in ammonium concentration during different levels of work out intensity, we point out a different behavior of what is expected physiologically. With this the importance of consideration of several parameters during sweating, like the sweat rate and other ingredients in human sweat, was demonstrated for correct determination of the ammonium concentration.

Closed Loop Experiment Manager (CLEM)-An Open and Inexpensive Solution for Multichannel Electrophysiological Recordings and Closed Loop Experiments.

There is growing need for multichannel electrophysiological systems that record from and interact with neuronal systems in near real-time. Such systems are needed, for example, for closed loop, multichannel electrophysiological/optogenetic experimentation in vivo and in a variety of other neuronal preparations, or for developing and testing neuro-prosthetic devices, to name a few. Furthermore, there is a need for such systems to be inexpensive, reliable, user friendly, easy to set-up, open and expandable, and possess long life cycles in face of rapidly changing computing environments. Finally, they should provide powerful, yet reasonably easy to implement facilities for developing closed-loop protocols for interacting with neuronal systems. Here, we survey commercial and open source systems that address these needs to varying degrees. We then present our own solution, which we refer to as Closed Loop Experiments Manager (CLEM). CLEM is an open source, soft real-time, Microsoft Windows desktop application that is based on a single generic personal computer (PC) and an inexpensive, general-purpose data acquisition board. CLEM provides a fully functional, user-friendly graphical interface, possesses facilities for recording, presenting and logging electrophysiological data from up to 64 analog channels, and facilities for controlling external devices, such as stimulators, through digital and analog interfaces. Importantly, it includes facilities for running closed-loop protocols written in any programming language that can generate dynamic link libraries (DLLs). We describe the application, its architecture and facilities. We then demonstrate, using networks of cortical neurons growing on multielectrode arrays (MEA) that despite its reliance on generic hardware, its performance is appropriate for flexible, closed-loop experimentation at the neuronal network level.