Plug-in Data Acquisition Board Research Articles

Acquisition of fast transient signals in ICP-MS with enhanced time resolution

Improving time resolution in sector-field ICP-MS through use of a plug-in data acquisition board.

Real-Time Measurement of Friction Coefficient in the Frictional Performance Test of Brake Disk

Development and optimizing of friction material formula, oriented to improve the service life and security of brake disk, is largely based on advanced measurement method to accurately provide the friction coefficient. In this study, virtual instrumentation technique was used to design an automation measurement system of friction coefficient. With proper sensors, data of four measured variables such as temperature, rotation speed, pressure and friction torque are acquired by the computer combined with a plug-in data acquisition board. The system work principle, selection of sensors, multi-channel sampling, signal processing and anti-jamming measures have been presented in detail. Those functions of the software such as real-time data acquisition, dynamic wave displaying, high-speed report saving and inquiry, and so on, have been realized by LabWindows/CVI 7.1. The system works safely with high accuracy and friendly user interface in practical operation.

Modeling ADC Nonlinearity in Monte Carlo Procedures for Uncertainty Estimation

Monte Carlo procedures can be successfully employed to evaluate the uncertainty of measurements performed by digital processing of sampled data, provided that the uncertainties affecting the input samples are modeled correctly. The static nonlinearity is the most difficult error to be modeled, since the technical specifications provided by the manufacturers of the acquisition systems are not usually sufficient to describe the nonlinearity curve over the entire input range. Thus, suitable assumptions are needed and approximations are unavoidable. This paper focuses on measurement systems based on plug-in data acquisition boards, which are generally based on successive approximation register analog-to-digital conversion (ADC). A behavioral model is presented, according to which the overall nonlinearity is divided into two contributions: a smooth component, responsible for the macroscopic error trend in the output domain, and a component with sudden variations in the scale of values. Theoretical fundamentals of the method are reported, and experimental results highlighting the reliability of the proposed approach are discussed

Noncontacting detection in ultrasonic nondestructive evaluation of materials: Simple optical sensor and fiber-optic interferometric application

An optical displacement sensor based on the two-beam interferometry of coherent light using two principal diffracted orders of a fine reflection blazed grating is constructed. The inherent capability of the interferometer for absolute calibration, its maximum sensitivity adjustment, and the simplicity of the configuration of its components are explained. Utilization of a single-mode optical fiber in the test arm of the interferometer to enhance the geometric flexibility of the optical system is demonstrated. The sensor’s application in the noncontacting detection of stimulated ultrasonic stress waves for nondestructive evaluation of advanced composite materials is emphasized. The detected signal is digitized and recorded using an IBM PC with a plug-in data-acquisition board. The combination of high sampling rate capability of the device and optical detection has facilitated the signal processing of ultrasonic waves in order to achieve interpretation and quantification of the physical parameter of interest (i.e., displacement).