Virtual Instrument Software Architecture Research Articles

Experimental research on terahertz scanning imaging system based on S-parameters

Due to the limitations of the detector in the terahertz (THz) scanning imaging process and the problems of low contrast and poor visualization effect of original image, a THz continuous-wave scanning imaging system from 75 to 110 GHz is presented. The system is comprised of vector network analyzer (VNA), spread spectrum module, transmit and receive antennas, scanning stage and host computer. In addition, the automatic acquisition and storage of S-parameters is realized by Virtual Instrument Software Architecture (VISA) protocol, and the gray imaging method based on S-parameters is proposed. High-precision structural resolution test board is designed based on printed circuit board (PCB) method and the imaging experiment for the resolution test board is carried out. By comparing with original imaging results, better imaging quality of the system designed in this paper is obtained and imaging results show that the resolution of 1.8 mm could be achieved.

Performance analysis and enhancement of brain emotion-based intelligent controller and its impact on PMBLDC motor drive for electric vehicle applications

ABSTRACT Growing awareness of electric vehicles insists on the necessity of Permanent Magnet Brushless Direct Current Motor (PMBLDCM) worldwide. This paper involves building a simulation model of the complete PMBLDCM drive system using Matlab/Simulink to control the speed and Torque. Using the Simulink model, speed parameters with various controllers of the drive system are studied and analyzed. The conventional PI controller is capable of controlling the speed of the PMBLDC motor. H1owever, it cannot give assurance of the stability of the motor throughout the load variation. In a speed loop, Improved Brain Emotional Learning Based Intelligent Controller (IBELBIC) is proposed in this paper. The proposed IBELBIC-based PMBLDC motor drive system with a rating of 3 phase, 30 V, 400 W, 3000 RPM is implemented using Spartan 3 Field Programmable Gate Array (FPGA) from Xilinx. This paper presents an IBELBIC design for enhancing the speed performance of the drive system at various set speeds and different load conditions of 1.2 Nm load, 0.6 Nm load, and no load. The proposed PMBLDCM drive system is realized with the help of a Very high speed integrated circuit Hardware Description Language (VHDL) programming algorithm of digital Pulse Width Modulation (PWM) generator topology. Various test cases are evaluated under different operating conditions to demonstrate the learning capability and the applicability of the proposed controller. In this paper, simulation validation is done using hardware setup, and experimental results are monitored on a computer using a customized program developed using LabVIEW (Laboratory Virtual Instrumentation Engineering Workbench). Instead of a Data Acquisition (DAQ) card, the Virtual Instrument Software Architecture (VISA) tool of LabVIEW software is used in this work and results in cost minimization of the experimental setup.

SCPI based integrated test and measurement environment using LabVIEW

Test and Measurement processes play a vital role on the quality of hardware functionality testing. Automating these processes provides a better reduction in “time to market” and is more concerned on achieving higher test coverage area when it comes to mass production. Functional testing deals with the observation on the characteristics of the hardware to determine whether it replicates the needs for which it was actually designed. This can be achieved using set of Test and Measurement Instruments which can replicate the environmental condition in which the hardware is to be deployed. This paper provides an environment to integrate set of measurement instruments in a single platform (LabVIEW) and automate the measurement control using command language know as Standard Command for Programmable Instrumentation (SCPI). Script based control commands provide an easy configuration and remote control of instruments. And also programming interface control using Virtual Instrument Software Architecture (VISA) to control instruments using Ethernet and USB protocol.

A Wireless Instrumentation Control System Based on Low-Cost Single Board Computer Gateways

Nowadays, most of the automatized measurement processes are carried out by VISA (Virtual Instrument Software Architecture) compatible instruments, that execute the instructions provided by a host computer connected through wired standard buses, as USB (Universal Serial Bus), GPIB (General-Purpose Instrumentation Bus), PXI (PCI eXtensions for Instrumentation) or Ethernet. To overcome the intrinsic limitations associated to these wired systems, this work presents an instrumentation control system based on the IEEE 802.11 wireless communications standard. Intended for instruments having a USB control port, this port is connected to a gateway based on a compact Raspberry Single Board Computer (SBC) and thus the instrument can be connected to the host computer via Wireless Fidelity (WiFi), easily allowing the deployment of an ad-hoc instruments communication network in the working area or its connection to a previously deployed general purpose WiFi network. Developed under Python, the operation commands, wireless link protocol, and USB connection allow two modes of operation to provide system flexibility: a live mode, where commands are sent individually from the host computer to the selected instrument; and a standalone mode, where a full measurement process can be entirely downloaded in the gateway to be autonomously executed on the instrumentation. The system performance in both operation modes, distance of operation, time latencies, and operating lifetime in battery operation have been characterized.

Remote Access Web System to VISA Architecture Measurement Equipment

The advancement in studies and research on remote experimentation and remote laboratories is very important in developing communication tools between the users and the remote laboratory. This paper presents the architecture and the implementation of a web system of remote access for measurement equipment which provides in its specifications the architecture VISA (Virtual Instrument Software Architecture). The majority of equipments have this architecture, and it is available in oscilloscopes, function generators and other measurement equipments from the field of electrical engineering. A prototype was created with the added functionality of remotely controlling a measuring equipment with VISA. It is shown that the proposed system brings benefits to the response time, decrease in deployment time and reduction in overall costs.

Network Agent Based on VISA Framework for Instruments

With the rapid development of computer networks,more and more measurements need to relay on the network.But there are only a small amount of instruments with network interface.To access the network,we design a network agent for the instruments with different interfaces. We connect the host with the instrument through the network agent.The agent communicates with the host by using HiSLIP(High-Speed LAN Instrument Protocol ).The client soft front panel controls the instrument based on the VISA(Virtual Instrument Software Architecture) and HiSLIP.We use the Labwindow/CVI to design the soft panel.We can use the soft front panel to manipulate the instrument by the agent quickly and easily.

Network Agent Based on VISA Framework for Instruments

With the rapid development of computer networks,more and more measurements need to relay on the network.But there are only a small amount of instruments with network interface.To access the network,we design a network agent for the instruments with different interfaces. We connect the host with the instrument through the network agent.The agent communicates with the host by using HiSLIP(High-Speed LAN Instrument Protocol ).The client soft front panel controls the instrument based on the VISA(Virtual Instrument Software Architecture) and HiSLIP.We use the Labwindow/CVI to design the soft panel.We can use the soft front panel to manipulate the instrument by the agent quickly and easily.

Microwave System for Head Imaging

A wideband microwave system for head imaging is presented. The system includes an array of 16 corrugated tapered slot antennas that are installed on an adjustable platform. A switching device is used to enable the antennas to sequentially send a wideband 1-4 GHz microwave signal and capture the backscattered signals. Those signals are recorded using suitably designed virtual instrument software architecture. To test the capability of the system to detect brain injuries, a low-cost mixture of materials that emulate the frequency-dispersive electrical properties of the major brain tissues across the frequency band 1-4 GHz are used to construct a realistic-shape head phantom. A target that emulates a realistic hemorrhage stroke is fabricated and inserted in two different locations inside the fabricated head phantom. A preprocessing algorithm that utilizes the symmetry of the two halves of human head is used to extract the target response from the background reflections. A post-processing confocal algorithm is used to get an image of the phantom and to accurately detect the presence and location of the stroke.

Design of the Sub-wavelength Gratings Applying to Optical Current Transducers

In the optical current transformer the sub-wavelength metallic gratings are hopeful to substitute the traditional polarizer because of their excellent optical properties. In this paper, a powerful analysis and design tool used for the sub-wavelength grating is proposed based on Matlab and LabVIEW virtual instrument software architecture. The RCWA (coupled-wave analysis) accompany with the enhanced transmittance matrix approach and the method of Fourier factorization is applied for the analysis of the grating. In the software platform, the users can visually and simply design a grating with arbitrary groove profile or intelligently extract the groove profile from the grating actually produced by image processing. The values of the diffraction efficiency and grating extinction ratio depend on the various parameters of the grating and incident light can be analyzed through the results in the form of charts and tables.

Design of EMC Test Software Based on Configurable File

According to EMC Standard,fulfilling one Test-Item generally includes below process: select and configure the parameters of instrument,form and execute the Test-Flow, therefore the main task of EMC is to configure instrument and form the Test-Item. In this paper the authors present a new method using configuration file to describe EMC Test-Item to improve the expansibility and maintainability of EMC test software. Multi-layered software architecture is designed according to EMC test operating sequence, and COM component technology is used to design the core module of each layer to guarantee plug&play for the new program-controlled instruments. Because of using the form of configuration file to describe Test-Item, the new Test-Item will be produced through Test-Engine calling Test-Item Configuration Generator. The Virtual Instrument Software Architecture is used to design and realize the frame of EMC software, and the Visual C++ software platform is used to realize the above design method. Application using configuration file make EMC software has the features of easy to use, easy update and expandability.

Software architecture for building

Test system developers can benefit greatly from a software architecture that allows for easy interchangeability of instruments in those systems. Using open industry standard software architectures such as Virtual Instrument Software Architecture (VISA), and Interchangeable Virtual Instruments (IVI), developers are able to create systems with interchangeable test instrumentation. This paper describes the VISA and IVI software standards and demonstrates how their use within a broader software architecture, which includes standard development environments and flexible test executive software, facilitates the creation of interchangeable test systems.