DE2204377

1380181 Data processing; measuring digitally PERKIN-ELMER CORP 1 Feb 1972 [1 Feb 1971] 4685/72 Headings G4A and G4H A plurality of analytical instruments, such as gas chromatographs or spectrographs are interfaced with a digital computer by way of voltage to frequency converters and registers for integrating pulses from the converters. In the system described, the instruments are individually addressed by the computer under program control, or may cause program interrupts, for the transfer of information between the computer and each instrument, e.g. to effect print-out at the instrument location. The computer is preferably programmed to selectively vary the gain of an amplifier preceding the analogue to frequency converter, to regularly sample the contents of the integrating register, to identify signal peaks and to determine their area relative to the signal base line. The program may also be arranged to analyse the output supplied by an instrument when no true signal is present and thereafter to set threshold levels for parameters such as the area under peaks. The computer may comprise a plurality of accumulator registers together with the usual memory address and data registers and an arithmetic and logic unit for performing arithmetic, logic, and shift operations on data in the accumulator and memory data registers, the analogue to frequency converters being at the instrument locations and the integrating registers being at the computer location.