Study On Multitask Real-time Measurement And Control System Based On RTX And LabVIEW

Multitask real-time measurement and control systems are widely used in our society, and real-time systems are reseach hot spots now. Most real-time systems which are of special purpose using special hardwares are special. These systems are not universal and have a little extension, so they can't be used freely. But the real-time system based on industrial computer can conquer the defaults of the former syetems.This paper presents a new kind real-time system. The hardware of the system is industrial compuer, and Windows 2000+RTX is the softeware of the system. In the system, the human interface and network communication programes are designed in LabVIEW.At the beginning of this paper, the limitation of Windows real-time performance is analysed. In order to add'hard'real-time capabilities to Windows 2000, this paper choses RTX developed by Ardence. The structure and scheduling policy of RTX are also analysed in this paper.Next the multitask real-time measurement and control system is designed. In the system the taskes are divided into two parts: real-time and non real-time. The real-time tasks run under RTSS subsystem, as the mean time non real-time tasks run under Win32 subsystem. The two parts communicate with each other through shared memory. Using CIN node to load extra codes in LabVIEW, the shared memory can be read and written.Then the whole system is introduced in detail. The real-time part includes analog signal acquisition, switch signal acquisition, temperature measurement, setp motor control, direct current motor speed measure and control. Real-time part programs are designed in Visual C++ using API provided by RTX. Non real-time part includes human computer interface and network communication. The non real-time part program is designed in LabVIEW, and network communication is based on TCP/IP protocol.At the end, the real-time and non real-time parts are combined together. The whole system is tested using RTX tools. The test results and performences of the system show that this excogitation meets the real-time and stability requirements, so this excogitation is feasible.