A VERSATILE MICRO-COMPUTER CONTROLLED HIGH SPEED DATA ACQUISITION SYSTEM APPLIED TO COMPRESSORS

摘要

A brief account is given of an early system used in 1967 and 1973 to acquire experimental data from reciprocating compressors. The later system was controlled by a mini-computer, had a multiplexed configuration, and had to operate in real time. Data could be read at a rate up to 100,000 readings per second: the maximum rate per channel was inversely proportional to the number of channels employed. A description follows of a parallel configured system developed in 1982 which is capable of data acquisition at the rate of 33,000 readings per second for each channel with virtually no limit on the number of channels which can be employed. Each channel is fitted with an individual analog-digital converter and digital store and operates in real time: channels are triggered and read simultaneously and data is subsequently transferred relatively slowly from, the digital store to the memory of the controlling micro-computer. The transferred data can then be processed and either stored or displayed in digital or graphical form. The system has operational advantages over, and is cheaper than, the earlier multiplexed system. One of its many applications is to measure the pressure in a cell of a sliding-vane oil-flooded rotary air compressor during a cycle of operation.