Abstract: A vibration monitoring apparatus for monitoring vibrating conditions of a plurality of rotary machines comprising a signal processor for processing actual data relative to levels of vibrations of the rotary machines and a control processor for storing in memory reference data relative to selected rotational frequencies and corresponding alarm levels for the rotary machines. The vibration waveform of one vibration sensor selected by a scanner is converted by an A/D converter into digital data to be supplied to the signal processor through a shift register. The signal processor is operated under program control to determine the peak-to-peak magnitude of the vibration waveform and compares it with the alarm level provided from the control processor.

Abstract: An apparatus monitoring the vibrations of a rotary machine precisely at all times. In a control processor, a rotational frequency is calculated with a data signal from a register which operates on the basis of period pulses from a key phaser, while a vibration level corresponding to the rotational frequency is read out of a memory, and an alarm level obtained by giving the vibration level a constant from an alarm level setting unit is sent to a signal processor. The vibration waveform of a vibration sensor selected by a scanner is converted by an A/D converter into a digital signal, which is applied to the signal processor through a shift register. In the signal processor, the alarm level from the control processor is compared with vibration data from the shift register, and the calculated result is sent to the control processor. The control processor operates output appliances on the basis of the information from the signal processor.