The Development and Use of Data Acquisition and Control Systems Based on Arm Microcontrollers

Abstract

A. E. Vasil'ev and I. V. Kolodeznikov UDC 004.3 Data acquisition and control systems as a combination of a personal computer and an ARM microcontroller with additional circuitry are considered. It is shown that the separation of the interface functions and the interaction functions with the object being controlled between separate modules guarantees that the system will operate in hard real time and makes it easy to use at low cost. A description of a practical system is presented.The construction of modern data acquisition and control systems is based on the use of computational techniques. The basis of such systems are platforms of general-purpose computer systems, i.e., personal computers (PC) or specialized systems.The use of a personal computer as the basis of a data acquisition and control system has an obvious advantage, namely, universality, which consists of the interchangeability of the computer components, in particular, when carrying out repairs or modernization, for example, to increase the disk memory, reduce the requirements regarding the qualifi cations of the operator to operate with them, the existence of typical ergonomic solutions for the user interfaces, etc. In view of the fact that in a general-purpose PC it is not possible to exchange physical signals with the object, the computer must be supplied with a special input-output circuit board, i.e., a matching device (MD). Suppliers of computer equipment have a large variety of such matching devices with different functional characteristics [1, 2].Despite the many versions of the technical solutions, they can be regarded as belonging to one of two predominant groups: matching devices having maximum simplicity or matching devices with the greatest autonomy. In the fi rst case, the device contains only components which transform a specifi ed signal parameter (amplitude, frequency or phase shift) into a numerical form and transmit these data for display on the personal computer. In the second case, the matching device has its own memory for storing the results of measurements and acquires data according to a specifi ed schedule, for example, periodically under the control of its own time-setting components.Solutions of the fi rst kind impose high requirements on the speed of response of the computer and the software (in particular, on the operational system) to ensure that the measurement system operates in hard real time, in other words, with a guarantee that each data processing and control cycle is carried out in a time interval not exceeding a previously specifi ed one. Solutions of the second kind are costly and insuffi ciently universal, since they have a limited number of adjustment versions, etc. Control of an object with a specifi ed arbitrary algorithm is only possible when using a matching device of the fi rst kind with the above specifi ed limitations.The list of specialized data acquisition and control platforms is extremely diverse because of the narrow specialization of such solutions. Their characteristic features may include ...