DATA-ACQUISITION AND MULTICHANNEL CONTROL-SYSTEM BASED ON DISTRIBUTED REALTIME-VXI SYSTEM

VXIbus systems with embedded PC and MS-DOS operation system commercially available are not sufficient in accordance with the requirements of fast data acquisition and multichannel control for mechanical quantifies rapidly varying with time. To overcome these limitations, VAX controllers and realtime software are used instead of an embedded PC int VXIbus systems. A distributed realtime data acquisition and multichannel control system (DAMCS) meeting the requirement of the fast dynamic calibration of vibration measurement devices has been developed. With the DAMCS, a data acquisition rate of more than 400 000 words/second in normal operation, and of approx. 1,2 million words/second in FIFO-DMA operation has been achieved. The network system has direct access to several 48 Mbyte main memories and to a 4 Gbyte hard disk. The cycle time achieved for the central unit is 30 mu s. Data acquisition and compensation of disturbances take place synchronously while electric input signals are continually generated for electromechanical exciters. The described system is used for the calibration of the amplitude-frequency and phase-frequency response of accelerometers, angular accelerometers and transducers for other motion quantities. It will be extended and further developed for the highly precise dynamic measurement of the mechanical quantities afforce and torque.