FFT Comparator
CF-4700A
To customers who are about to start pass/fail judgment based on frequency spectrum.
The CF-4700A FFT Comparator is an in-line pass/fail judgment instrument ideal for precise quality inspection based on the sounds and vibrations of products. Equipped with our company’s frequency analysis technology using FFT, developed over many years, it extracts characteristic frequency components that indicate problems and performs pass/fail judgment.
In addition to the judgment functions of its predecessor, the CF-4500, which assess the magnitude of frequency components and waveform shapes, this model features a fluctuation component extraction function that extracts the amount of variation in periodically fluctuating sounds and vibrations and makes judgments based on that variation. Rather than assessing sound or vibration frequency levels, this function judges based on the amount of periodic fluctuation. It can therefore perform pass/fail judgment for sounds such as the rough “whirring” noise and “rattling” vibration that occur when motor-driven equipment is operating. The unit can also monitor bearing vibrations using the band-pass filter and envelope functions included in the fluctuation component extraction function, and perform auditory checks by making vibrations audible through the monitor function (headphone output).
A new judgment assist function makes it easy to set the judgment range.
It reads the differences in sound and vibration levels from measurement data files for both pass and fail results, then sets the judgment blocks. This makes it easy even for customers using frequency spectra for pass/fail judgment for the first time to set the blocks.
The block comparator is a function that performs judgment based on a set range (area) at any frequency and level. It determines whether the peak value or level of the signal of interest matches the set conditions. There are six types of judgment methods for the signal: level, peak level, peak max, inside max, partial overall, and area inclusion rate. The setting of the judgment block can be done by dragging while touching the screen on the waveform, or by entering values in a list display.
Related Functions
Block comparator function (standard function)
Judgment criteria calculation assist function (standard function)
The shape comparator is a function that determines pass or fail based on the shape of waveforms. It can set a judgment line to assess subtle changes that appear in time waveforms or differences in the shape of spectra. In time waveforms, to prevent misjudgment due to instantaneous noise, if the number of data points exceeding the judgment level is below a set value, it can be considered noise and excluded from the judgment target.
Related Functions
CF-0472 Shape Comparator Function (Optional)
When addressing vibration and noise in rotating equipment, it is important to measure and analyze the rotational speeds at which vibration or noise increases, as well as which components of the rotating machine are causing it. The CF-4700A FFT Comparator tracks changes in rotational speed to extract vibration and noise components caused by rotation, and can determine whether the equipment is operating properly based on their levels or how they change.
Related Functions
CF-0472 Shape Comparator Function (optional)
CF-0471 Tracking Function (optional)
The fluctuation component extraction function is a preprocessing function that extracts the "amount of fluctuation" in the magnitude of signals in specific frequency bands. It is effective for determining abnormal sounds and vibrations caused by changes in magnitude, and can be used as preprocessing for pass/fail judgments of noises such as "ghee" and "katakata" that occur when equipment using motors is operating. Additionally, it allows for vibration monitoring of bearings using the bandpass filter and envelope functions included in the fluctuation component extraction function, as well as the audible representation of vibrations through the monitoring function (headphone output).
Related Functions
CF-0473A Fluctuation Component Extraction Function (Optional)
In the production site, unexpected momentary power outages or significant voltage drops can occur in the main power supply line. By equipping this option, the machine can secure enough power to shut down normally even if the main power supply line goes down, eliminating the need to prepare a separate uninterruptible power supply. Additionally, if the startup conditions are set in advance, there is no need to reset the measurement conditions again when the power is restored. By using this function, centralized management of power with the main power supply ON/OFF of the line becomes possible, and the power ON/OFF of this machine becomes unnecessary.
Related Functions
CF-0478A Power Backup Function (Optional)
When opening and closing the door mirror, if there is uneven rotation of the motor, a murky abnormal noise with periodic fluctuation components may occur. Therefore, we measure the sound of the door mirror's opening and closing state using the MI-1235 1/2 inch measurement microphone + MI-3111 microphone preamplifier, and extract the periodic fluctuations using the fluctuation component extraction function to determine the presence of abnormal noise based on the amount of fluctuation. By using the fluctuation component extraction function, it is possible to judge sounds that cannot be determined simply by the level of loudness.
Function Used
CF-0473A Fluctuation Component Extraction Function
When damage occurs to a bearing, abnormal vibration is generated. The signal from an accelerometer attached to the rolling bearing is input to the CF-4700A FFT Comparator. A band-pass filter included in the optional fluctuation component extraction function filters the frequency band of the vibration generated by the damage, and the envelope function analyzes the fundamental frequency corresponding to the damaged part. The condition of the bearing is monitored based on the amplitude at that frequency to determine when maintenance is needed. The filter can also be set by listening to the sound through the headphone output.
Functions Used
CF-0473A Fluctuation Component Extraction Function
We track and analyze the vibration signals of the transmission and perform quality control at that level. We conduct tracking analysis by receiving rotation pulses from the rotation control controller of the transmission testing machine. We measure the vibrations when the rotational speed varies from idling to maximum output using the NP-3000 series built-in preamplifier accelerometer, and perform rotational tracking analysis of the meshing order. We set arbitrary judgment lines on the analyzed tracking data to determine the OK/NG of the transmission.
Functionality Used
CF-0471 Tracking Function + CF-0472 Shape Comparator Function
The frequency spectrum of the sound produced when metal parts (such as cast components) are struck changes if they have cracks or fractures. To inspect them, the metal parts are suspended by a thread or otherwise placed in a free-vibration state, then tested using the sound radiated when they are struck. The sound produced by striking the part with a hammer is captured using an LA-4440 integrating-averaging precision sound level meter. Its AC output is fed into a CF-4700A FFT Comparator for frequency analysis. Based on the differences in spectrum shape between good and defective parts, the shape of the shape comparator is configured to determine OK/NG.
Functions Used
CF-0472 Shape Comparator Function
Electronic components on a power supply board may produce sounds at the power supply frequency or at high frequencies. To avoid the effects of background noise, a simple anechoic box is used to measure abnormal sounds generated by the power supply board. A MI-1235 1/2-inch measurement microphone and MI-3111 microphone preamplifier installed inside the anechoic box capture the sound from the board, and the signal is input to the CF-4700A FFT Comparator for frequency analysis. A judgment block is configured to cover the frequency at which the abnormal sound occurs, and OK/NG is determined based on the spectrum area ratio.
Functions Used
Block Comparator function
Mechanical components, such as harness assemblies built into automotive sliding door mechanisms, can produce abnormal sounds during operation. To measure the sound generated as the harness is wound up, the motor of a harness assembly placed inside a simple soundproof box is driven. The noise level is checked using an LA-1410 integrating-averaging sound level meter inside the box, while the AC output signal from the sound level meter is fed into a CF-4700A FFT Comparator for frequency analysis. Comparative judgments are made based on the partial overall level in a specific frequency band.
Functions Used
Block Comparator function
When an imbalance occurs in the turbo fan, the signal from the vibration sensor increases. Therefore, vibration is measured while the turbo fan is rotating. Using the signal from the NP-3000 Series accelerometer with built-in preamplifier, set the frequency band of interest and the judgment level with the CF-4700A FFT Comparator, then configure the judgment block. Select Peak Max as the judgment method. If the waveform's MAX value (local maximum) is within the configured block area, the result is judged OK; otherwise, it is judged NG.
Functions Used
Block Comparator function
| Digital I/O | Recommended Connection Circuit / Specifications | |
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| DIGITAL INPUT We will assign and use the following functions.
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Input type: Driven by contact or open collector (common isolated) Logic: Negative logic (Lo=1, Hi=0) |
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STATUS OUTPUT
It is a terminal that outputs. |
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| Output type: Open collector (independent 4 points, each signal isolated) Output voltage: 30 V Output current: Maximum 25 mA (sink) Collector saturation voltage: Below 1.0 V Logic: Negative logic (Lo=1, Hi=0) Compatible connector: FK-MC 0.5/8-ST-2.5 (Phoenix Contact standard accessory) |
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| COMP OUTPUT Select any 5 from 20 judgment settings, and this is the terminal that outputs the results. |
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| Output type: Open collector (5 points + common total isolation) Output voltage: 30 V Output current: Maximum 25 mA (sink) Collector saturation voltage: Below 1.0 V Logic: Negative logic (Lo=1, Hi=0) Compatible connector: FK-MC 0.5/6-ST-2.5 (Phoenix Contact standard accessory) |
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| power rating | DC 16 V 3.3 A |
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| AC adapter | Power rating: AC 100-240 V 50/60 Hz Power consumption: 65 VA or less / 150 VA or less (CF-0478A with power backup function: during battery charging) |
| Operating temperature range | 0 to 40 °C (humidity 20 to 80 %RH, with no condensation) |
| Storage Temperature Range | -10 to +50 °C (humidity 20 to 80 %RH, without condensation) |
| Outline Dimensions | 220 (W) × 185 (H) × 220 (D) mm (excluding handle, stand, and protrusions)
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| Weight | Weight without options: approximately 2.8 kg Weight with options: approximately 3.3 kg (When equipped with CF-0473A variable component extraction function and CF-0478A power backup function, including battery pack) |
| Main body cooling | natural air cooling (fanless) |
| Applicable Standards | CE marking |
| vibration resistant | 9.8 m/s 2 (frequency 10 to 150 Hz, in all XYZ directions) |
| shock resistant | 400 m/s 2 (action time 11 ms) |
| Accessories | • AC adapter x 1 (PS-P20023, VM1391-VM1700 (2 m)) • Instruction manual x 1 • CD-ROM x 1 (Reference guide, utilities, external control DLL, etc.) • SD card x 1 (For updates only 512 MB) • Terminal block connectors 3 types x 1 (FK-MC 0.5/10-ST-2.5, FK-MC 0.5/8-ST-2.5, FK-MC 0.5/6-ST-2.5) • Ferrite core x 1 (Seiwa Electric: E04SR301334) |
