How to use an oscilloscope as a waveform recorder

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This post was last edited by Mackoxin Instruments - Wheat on 2020-5-8 at 15:03. A waveform recorder can collect signals over an extended period of time and save the data on the device’s hard drive. The duration of data collection depends on the sampling rate and the capacity of the hard drive. However, unlike an oscilloscope, it does not have the capability for real-time analysis, which is precisely the strength of an oscilloscope. An oscilloscope can perform real-time analysis of waveforms while collecting them over a long period of time. However, the oscilloscope is not equipped with a large-capacity hard drive; to use the oscilloscope as a recorder, it is necessary to make use of its storage depth function. Next, let’s take a look at how to use an oscilloscope as a waveform recorder. First, we’ll cover the relevant basic concepts. To record waveforms over a long period of time, the sampling rate, storage depth, and waveform recording duration are all important factors; storage capacity is a key indicator in this regard. Both the STO and TO series from Micronox feature a storage depth of at least 28M points (the STO1000E can reach 70Mpts). According to the formula: Sampling rate = Storage depth ÷ Waveform recording duration, where the storage depth remains a constant value, while the sampling rate changes depending on the waveform recording duration we set. For example, when the storage depth is 28M and the time base is set to 2ms, the waveform recording duration is 28ms; thus the sampling rate is 0.028G (28M) ÷ 0.028s (28ms) = 1GSa/s. When the time base is 4ms, using the same calculation, the sampling rate becomes 500MSa/s. When using the oscilloscope as a recorder, the storage depth setting is an important factor. To make the most of the oscilloscope’s capability for long-duration recording thanks to its large storage depth, it is necessary to set the storage depth to its maximum value first. Open the oscilloscope’s user settings menu, locate the recording length (i.e., storage depth), and set it to 28/14/7M in the settings menu – this represents the maximum value. Keep only one channel active and turn off the other channels. Only in single-channel mode can the storage depth reach its maximum value. Then set the time base to 1ks/div; as shown in the figure below, the oscilloscope will automatically enter scroll mode. Alternatively, you can go to the display menu of the oscilloscope, select Settings, and manually enable scrolling. Data export and utilization: Once the oscilloscope has recorded a full screen of waveforms, the recorded waveform data can be saved. By opening the oscilloscope’s save menu, it is possible to save waveforms in WAV, CSV, or BIN format, and it is also possible to name the waveform data. WAV: The first method for saving data files. It involves sampling the waveform data displayed on the screen and saving it as a binary file in WAV format, which can then be stored locally or in external memory. Such files can be opened and viewed, as well as scaled, on the same device. CSV: This is the second method for saving data files. It stores the waveform data of the oscilloscope’s current channels in CSV format, either in the oscilloscope’s internal memory or on an external storage device such as a USB drive. It is a comma-separated values file format that stores tabular data in plain text form; it converts any binary data required into ASCII code before storing it, allowing the file to be opened using Excel, Access, or plain text editors. It cannot be accessed directly on the local machine. The image below shows the interface after opening a CSV file in Excel; the line graph in the lower part is created using values from columns E and F as coordinates: https://pic3.zhimg.com/80/v2-8f42e5e2ed4843b41cd6b860bd5994b6_720w.jpg Due to storage limitations, data files saved in WAV and CSV formats are also sampled (there are 87,500 data points shown in the image), which allows most of the signal information to be retained while keeping the data storage time within 2 seconds. https://pic3.zhimg.com/80/v2-c9c7b258bc89492ec4c40c3bc265910e_720w.jpg So, for those who need to save the entire 28M waveform data on one screen, do they really have to wait hours for the oscilloscope to complete the storage? There’s no need to rush; the Mackox oscilloscope provides a third method of storage for such needs: BIN. The specific steps for this process are shown in the figure below, and the entire procedure takes less than 60 seconds, allowing you to work with huge amounts of data amounting to tens of millions.