Data Recording and Replay

Real-time acquisition, recording, replay and offline review run in the same software. During a test the data scrolls on screen and is saved automatically. After the test, every recorded frame can be analyzed again as a spectrum, color map or waterfall. What was missed during the test can be reviewed afterwards.

Separate communication service

A communication service that runs separately from the analysis interface moves data from the acquisition hardware to the software. The two programs exchange data through an internal high-speed channel. Data reception, organization and storage continue in the background even while the interface draws complex graphs or computes large spectra, so long unattended tests do not freeze the interface or lose data.

• Direct connection to the acquisition hardware; every frame is received within milliseconds.
• Automatic reconnection after a communication fault, with an optional request to the hardware to reduce its rate for protection.
• Background storage: the service writes recorded data directly to disk, independent of the display.

A signal cannot be repeated. A shock, a fault or a sweep happens once. The live screen shows what is happening now; a recording answers what happened and why.

• Preserve transient events: shocks, abnormal noise and sudden changes cannot be reproduced, and the recording is the only evidence.
• Analyze offline in depth: during the test only one or two windows are watched; afterwards the data can be analyzed with color maps, waterfalls and audio.
• Keep quality records: one recording per product, with measurement notes, forms a traceable electronic record.
• Share and collaborate: recordings can be replayed and analyzed without the instrument.
• Reduce cost: one test can be reused many times, reducing repeated test runs.

Before a measurement starts, a data-save dialog sets the storage location, file naming, recording mode and storage rate. The dialog estimates the recording duration and the required storage space and shows the free disk space, so storage problems are found before recording starts.

Three recording modes

Recording rate

• Total stored frames: 1 to 16384, which sets the recording capacity together with the mode.
• Frame storage interval: 1 to 500 (for example, store every frame). A larger interval covers a longer time with the same number of frames.
• Automatic file organization: each recording creates its own folder with matching parameter and data files. Data is split into volumes of a fixed number of frames (Record_0000, Record_0001 …), and each volume can be opened on its own.
• Sequence numbering: renumber or overwrite the previous recording, so batch tests do not create duplicate names or delete data by mistake.

Protection against power loss

The background service writes data to disk during acquisition and commits it every 256 frames. After an unexpected power failure or program exit, most of the data remains intact in the data volumes.

Measurement notes

Test conditions, part numbers and operating conditions can be entered as notes and are saved with the recording. A file information panel shows the total frames, frame length, number of points, sampling rate, storage type and recording duration.

When a test ends, or a previous recording is opened, the lower-left area of the main window changes to the replay panel. It lists all data volumes of the test; double-click a volume to load it and play back the test.

• File list: all data volumes of the current test, with the first, current and last frame and the storage number.
• Playback control: play, pause, stop, single-frame forward and back, a progress bar, and direct entry of any frame number.
• All windows update together: each replayed frame is treated as live data. The time waveform, spectrum, channel table and all extended analysis windows (spectrum, octave, demodulation, order tracking and others) update, and analysis parameters can be changed for offline reanalysis.
• Seamless switching: replay starts automatically when a measurement ends; a new measurement restores the acquisition view.

The review window loads a complete data volume and offers four overall views, linked frame by frame to the time waveform and spectrum below.

Amplitude bar chart: the whole test on one screen

Each frame of the volume is condensed into one bar, so abnormal frames such as shocks, exceedances or sudden changes stand out. Linear or logarithmic axes and automatic or manual ranges are available. Selecting a bar with the cursor shows that frame's waveform and spectrum. Each bar can show the maximum, minimum, RMS, peak-to-peak or maximum absolute value.

Frequency color map: the path of a changing frequency

For sweeps, speed changes and start-up or shutdown, the color map is the clearest view: bright ridges show how the dominant frequency moves with time. The crosshair reads the frame number, frequency and amplitude and shows that frame's waveform and spectrum. A logarithmic frequency axis and automatic ranging are supported.

3D waterfall

The spectra of all frames form a 3D surface that can be rotated, zoomed and panned, with preset top, front, side and free views. Linear or logarithmic amplitude axes are available, and the plot engine draws thousands of spectra quickly. The crosshair reads frame number, frequency and amplitude.

Audio playback: listening for faults

The recorded data of a selected channel can be converted to an audio file and played back in step with the progress bar. Many mechanical problems, such as abnormal noise, rubbing or looseness, are recognized faster by ear than from a spectrum.

Time-base scaling and export

• Combine several frames into one bar, or split one frame into several bars, to scale the time axis.
• Overlay multiple channels in the waveform and spectrum views.
• Export the bar chart image, a bar statistics table (maximum, minimum, RMS and peak-to-peak per frame), the complete waveform as Excel data, and color map and waterfall images for reports.

Set up and start recording

1. Click Start in the main window. The data-save dialog opens.
2. Confirm the save path and free disk space. Enter a file name prefix and select renumber or overwrite.
3. Select the recording mode: stop when full, circular or continuous.
4. Set the total stored frames and the storage interval. Check the estimated duration and storage space.
5. Enter measurement notes if needed and confirm. The status bar shows buffer and recording progress.

Stop and replay

1. Click Stop. The software saves the recording and enters replay mode.
2. Double-click a data volume in the file list to load it.
3. Use play, pause and step or the progress bar, or enter a frame number to go directly to it.
4. During replay, all open analysis windows update exactly as during live measurement.

Review in depth

1. Open the recording review window.
2. Select a data volume and check the file information: frames, points, sampling rate and duration.
3. Select the reference channel and the number of combined points; enable advanced analysis for the color map and waterfall.
4. Switch between the bar chart, color map and waterfall, and move the cursor to update the waveform and spectrum.
5. Use audio playback to listen to the data.
6. Export images and data tables for the report.
7. Return to the main window to continue frame-by-frame replay.

A rotating machine is tested during run-up and run-down with a swept-sine excitation. Sampling rate 25.6 kHz, 1024 points per frame, stop-when-full mode, 4096 frames at an interval of 1. Recording duration depends on the actual frame-save cadence and is not established by this example.

Interpreting the result

• A steady bar chart without isolated spikes indicates a normal test.
• A continuous, smooth ridge in the color map indicates good sweep control. Where the ridge dwells at one frequency and its amplitude rises, a resonance may be present; read the spectrum of the peak frame in detail.
• The waterfall view presents the frequency path and energy for reports.