FFT Applications
FFT OK/NG judgment, quality control (using PC or PLC* etc.)
Q-1-1 OK/NG judgment of metal parts by hammering sound
- In this example, the hammering sound of a metal part (e.g. a casting part) suspended in free vibration is measured by the LA-7500 Integrating sound level meter. The CF-4700A performs frequency analysis of the AC output from the LA-7500 to find difference of power spectrum shape between OK and NG products. The Shape comparator function of the CF-4700A can be used for OK/NG judgment by the difference of power spectrum shape. (option: CF-0472 Shape comparator function)
- Judgment area block (max: 20 blocks) is set up by the specified frequency range on the power spectrum and the upper/lower-limit levels.The most suitable judgment method can be selected from 6 kinds of judgment methods (level, peak level, peak max, insideMax, partial overall or area rate of content). The Digital I/O function also enables control by PLC*via comparator output.
- MI-1234 (microphone), MI-3111 (preamplifier), SR-2210 (sensor amplifier) and SC-2500 (sound calibrator) can be used in place of a sound level meter.
- Measurement result can be stored in a PC via LAN or RS-232C interface.
* PLC: Programmable Logic Controller
Product list
| Model | Product name | Remarks | Qty | |
|---|---|---|---|---|
| 1 | CF-4700A | FFT Comparator | 1 | |
| 2 | CF-0472 | Shape comparator function | 1 | |
| 3 | LA-7500 | Integrating Sound Level Meter | 1 |