2 – Software considerations

Publisher Summary Most of the problems that occur in designing data acquisition and control (DA&C) systems result from limitations imposed by software. This chapter discusses the main requirements of data-acquisition software and describes some of the problems posed by using operating systems intended for desktop applications in the more demanding environment of a real-time DA&C system. In addition to code that acquires data or issues control signals, it is usual for DA&C software to incorporate a number of support modules which allow the system to be configured and maintained. Other routines may be required for sorting, analyzing and displaying the acquired data. Data-acquisition systems that are designed for inspection or dimensional gauging applications may be required to gather data at only very low speeds. In these cases, the time taken to read and respond to a series of measurements may be unimportant. A real-time DA&C system is one in which the time take n to read data, process that data and then issue an appropriate response is negligible compared with the timescale over which significant changes can occur in the variables being monitored and/or controlled.