The influence of software timing error on measurement accuracy of data acquisition

The application of high-speed real-time data acquisition is becoming increasingly wide spread in industrial field, and its measurement accuracy is also increasing. The closed-loop test system of sine wave signal is constructed by the RIGOL’s DG1022 dual-channel signal source, DS1102C oscilloscope and PCI7489 multifunctional data acquisition card. Three kinds of timing methods, such as Visual Basics (VB) Timer control, multimedia timer function timing and query performance frequency function timing method, were carried out a series of comparative experiments. This paper analyzes the correlation characteristics of the measured voltage peak data, which includes mean value, variance, standard deviation, range, mutation system, deviation, kurtosis and so on, and then finds out the influence rules of software timing error on data acquisition and measurement accuracy. In the high-speed data acquisition, the repeatability error can be reduced from 84.22% to 0.62%, which provides scientific basis and reference for selecting software timing method in different test environment.

Data Receiving Method Based on Multimedia Timing in Real- Time System

Several methods, such as polling, multithread, timing, and so on, can be used in data receiving course. Low-efficiency and high level of system resource consumption may bring about data loss in polling and multithread methods when the data transmission rate is very high. Software timing methods are discussed and analyzed in Visual C++. Timing method would improve the system resource availability and decrease the risk of data loss. According to the demand ofatesting system,areal-time monitoring system based on memory sharing and multimedia timer is presented. After testing, the average timing error of the multimedia timer in the given instance is not bigger than 0.05%, so the continuity and integrity of data receiving can be assured under the conditions of high-speed data transmission.