FFT         OK/NG judgment, quality control (using PC or PLC* etc.)

Q-1-3      OK/NG judgment of a motor on a inspection line

  • This example shows how to make OK/NG judgment automatically by power spectrum of vibration during motor in operation. The Figure 1 shows the time waveform and its power spectrum of an OK (non-defective) product. The time waveform and its power spectrum of an NG product are shown in the Figure 2.
  • Some particular peaks are existing in higher frequency of the NG product than that of the OK product. The CF-4700A FFT comparator can make OK/NG judgment by setting judgment level around the frequency of target spectrum.

  • The block comparator function makes OK/NG judgment by the judgment block area (maximum setup: 20 blocks) set in a certain frequency range and level range. Level, peak level, peak max, section overall, areal rate of content judgment methods are available for each block. You can make OK/NG judgment with the most appropriate one selected from the five judgment methods. Also the digital I/O function enables control via PLC using comparator output.

  • The measurement results can be stored into a PC via LAN or RS-232C interface.


Product list

  Model Product name Remarks Qty
1 CF-4700A FFT Comparator 1
2 NP-3418 Accelerometer with built-in preamplifier 1
3 NP-0021 Miniature/BNC conversion connector 1