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Data Acquisition and Processing
Published in Ethirajan Rathakrishnan, Instrumentation, Measurements, and Experiments in Fluids, 2020
For a data acquisition system configured for laboratory applications, the personal computer (PC) may be employed as the controller. A number of measuring instruments, probes, and transducers can be connected to it through appropriate interfaces. In the case of digital instruments, they can be accessed and controlled remotely by a PC. In fact, all the operations which have to be done manually by pressing buttons on the operation panel of any digital instrument can be controlled by a PC. Ready-made standard interfaces are available for controlling digital instruments and also for digitizing analogue signals – A to D cards – and transferring them to the PC. The general purpose interface bus (GPIB) is the most widely used interface for the control of digital measuring equipment. This was developed by the Hewlett-Packard (HP) company in 1972 under the name of HP-IB for the interconnection of instruments. It served as the trend setter for further work in standardizing instrument interfaces and the IEEE-488 standard was finally published in 1975. Presently, GPIB is also called as IEEE-488 bus or HP-IB. For A to D conversion, several ADC/DAC cards are available from various manufacturers, which are IBM-PC compatible. These interface cards can directly be connected to the slots provided in the PC. Most of the cards offer 8 or 16 ADC channels, 1 or 2 DAC channels, and 8 or 16 channels of digital input/output. Additional features such as programmable gain in amplification, sample-and-hold, single ended or differential inputs and DMA are also available with these cards.
Digital Interfaces in Measurement Systems
Published in Robert B. Northrop, Introduction to Instrumentation and Measurements, 2018
The IEEE-488 bus was developed by HP in the early 1970s as a standard, 8-bit, bidirectional, asynchronous bus (HP-IB) to enable a number of HP-IB-compatible instruments to communicate with a controlling computer and with each other. Not only can measured data be sent to the host computer for storage and processing, but in certain GPIB-compatible instruments, the computer can be used to set the instrument’s front panel controls and to control the measurements. The original IEEE-488 standard was defined by the IEEE Standards Committee in 1975, and it was revised in 1978 and again in 1987 as IEEE Std. 488.2-1987. The IEEE 488.2 standard is also called the Standard Commands for Programmable Instruments (SCPI). The SCPI Consortium voted to become part of the IVI™ Foundation in late 2002, and the IVI Board of Directors voted to accept the merger in the spring of 2003, IVI assumed control of the SCPI specifications. (IVI stands for Interchangeable Virtual Instruments.) (See www.ivifoundation.org/ [accessed April 23, 2013.) The latest IVI specifications may be found at www.ivifoundation.org/specifications/default.aspx/ (accessed April 23, 2013).
Drivers
Published in Rick Bitter, Taqi Mohiuddin, Matt Nawrocki, LabVIEW™ Advanced Programming Techniques, 2017
Rick Bitter, Taqi Mohiuddin, Matt Nawrocki
The General Purpose Interface Bus (GPIB) is a standard method of communication between computer/controller and test equipment. The GPIB consists of 16 signal lines and 8 ground return lines. The 16 signal lines are made up of 8 data lines, 5 control lines, and 3 handshake lines. The GPIB interface was adopted as a standard (IEEE 488). The maximum GPIB data transfer rate is about IMbyte/sec. A later version of the standard with added features was defined in 1987. This standard is the ANSI/IEEE 488.2. This enhancement to the standard defines how the controller should manage the bus. The new standard includes definitions of standard messages for all compliant instruments, a method for reporting errors and other status information, and the protocols used to discover and conFigure GPIB 488.2 instruments connected to the bus.
Toxicological aspects of Campomanesia xanthocarpa Berg. associated with its phytochemical profile
Published in Journal of Toxicology and Environmental Health, Part A, 2019
Joubert Aires De Sousa, Lismare da Silva Prado, Bárbara Lopes Alderete, Fernanda Brião Menezes Boaretto, Mariangela C. Allgayer, Fabiano Moraes Miguel, Jayne Torres De Sousa, Norma Possa Marroni, Maria Luísa Brodt Lemes, Dione Silva Corrêa, Alexandre de Barros Falcão Ferraz, Jaqueline Nascimento Picada
Chromatographic analyses were carried out using a validated reverse-phase HPLC method (Waters 2695 Alliance Separation Module). The HPLC column was equipped with a Waters 2487 λ Dual Wavelength UV Detector controlled by an IEEE-488 interface module. As a stationary phase, a Waters Spherisorb ODS2 reverse phase column (250 x 4.6 mm, 5-µm particles) was employed. A constant flow rate of 1 ml/min was utilized during analysis. HPLC grade solvents and milli-Q water were used in the chromatographic studies. Contents of phenolic acids and flavonoids were quantitatively determined at 254 nm employing pure acetonitrile (A) and 0.1% phosphoric acid (H3PO4) (B) as mobile phases. The gradient system was adjusted at 0/95, 20/86, 70/65 (min/%B). The correlation of chromatographic peaks was achieved by comparing experimental retention times to those of reference standards. Their amounts were quantified by a standard curve, and the results are expressed in mg/L extract.
Calibration of Electrostatic Discharge (ESD) Generator in Accordance with IEC61000-4-2: 2008 at SCL
Published in NCSLI Measure, 2018
H. W. Lai, Michael W. K. Chow, K. Y. Chan
The first test requires an ESD target-attenuator-cable to convert current to voltage and a digital oscilloscope with bandwidth wider than 2 GHz to capture the current pulse waveform. The ESD target-attenuator-cable consists of an ESD target, a 20 dB attenuator and a cable. It is mounted on the copper wall of the shielded room (namely the Vertical Calibration Plane) with its target-face outside the shield room and its cable-face inside the shield. The target has a low resistance of 2 Ω on the test side. The geometries of the ESD target-attenuator-cable are shown in Figure 1. The digital oscilloscope is located inside the shielded enclosure room to prevent any radiating ESD signal from affecting the oscilloscope. It is connected to a personal computer via the IEEE-488 (GPIB) interface for taking the waveform.
The analysis of the electrical characteristics and interface state densities of Re/n-type Si Schottky barrier diodes at room temperature
Published in International Journal of Electronics, 2019
The I-Vand C-V measurements of Re/n-Si Schottky barrier diodes were measured using a Keithley 4200 I-V source and a HP model 4192A LF impedance analyser (513 MHz) at room temperature, respectively. At the same time, all measurements were carried out with the help of a microcomputer through an IEEE- 488 AC/DC converter card.