How to use an oscilloscope as a waveform recorder

An oscilloscope is a commonly used measuring instrument with powerful data acquisition and analysis capabilities. It can also export the acquired waveforms and analyze them on a computer. This function is very similar to a waveform recorder, so can we use an oscilloscope to achieve the same effect as a waveform recorder?

Traditional waveform recorders can collect signals for a long time and save the data to the hard disk of the device. The length of the acquisition time depends on the sampling rate and the hard disk capacity. Its disadvantage is that it does not have real-time analysis function, which happens to be the strength of oscilloscopes. Oscilloscopes can analyze waveforms while collecting for a long time. Oscilloscopes are not equipped with large-capacity hard disks. To use the oscilloscope as a recorder, the storage depth needs to be maximized.

1. Recording duration

To record waveforms for a long time, storage capacity is an important indicator. The ZDS4000 series oscilloscope is equipped with a maximum storage depth of 512M. We know that:

When the sampling rate is Sa = 20K/s,

That is, a maximum of 7.1 hours of waveform can be recorded in a single time, which can cope with most on-site test scenarios.

2. Sampling Settings

To fully utilize the long-term recording performance of the oscilloscope's large storage depth, you must first turn on the maximum storage depth. Set the storage depth to 512M in the setup menu, set the storage area to fixed, and keep the single channel open. In single-channel mode, the storage depth can reach the maximum. Then adjust the time base to 1ks/div, as shown in Figure 1 below, the oscilloscope will automatically enter the ROLL mode. The ROLL mode can also be turned on manually.

Figure 1 Sampling setup

As shown in the green box, the sampling time of the oscilloscope reaches 25.6ks, that is, 7.1 hours, and the sampling rate can be maintained at 20k/s. The rolling mode can ensure that the data will not be interrupted during these 7.1 hours and the latest data will be retained.

3. Data Export

After data acquisition, we can export and save the data in binary or CSV format, and then start the next round of sampling. This can achieve longer waveform recording. The oscilloscope supports three different export methods.

1. USB flash drive export

Using a USB flash drive to export is the most commonly used waveform extraction method. The advantage of this method is that it has no restrictions on usage scenarios and only requires a USB flash drive to complete the export operation. The method is as follows:

1) Insert the USB drive

2) Open the oscilloscope's Save/Recall menu

3) Select the storage type as binary file or CSV

4) Select the storage path as USB disk/udisk

5) Click Save File to export the waveform

Figure 2 USB disk export method

2. Supporting software Wave Analyze

The PC software Wave Analyze that comes with the ZDS oscilloscope has powerful functions, including waveform export. Wave Analyze is connected to the oscilloscope through the network, and the waveform collected by the oscilloscope can be uploaded to the PC for further analysis or exported as a file. This method requires the use of PC software, but the advantage is that waveform analysis can also be performed on the PC, which is more operable. The method is as follows:

1) Install the oscilloscope PC software

2) Use an Ethernet cable to connect the PC and the oscilloscope

3) Open the PC software and set the oscilloscope IP for connection

4) Click the capture button to capture a frame of waveform

5) Export waveform file

Figure 3 The waveform file exported by the host computer software

3. Web page access

The last method is to use a web page. ZDS oscilloscopes support web access. After connecting to the oscilloscope using the network, open the browser and enter the oscilloscope's IP address to access the oscilloscope. In the web page, you can remotely operate the oscilloscope through virtual buttons, and directly access the stored files in the oscilloscope. This method can export waveform files saved locally on the oscilloscope, and is also suitable for exporting screenshots, reports and other files. The method is as follows:

1) Save the waveform to the oscilloscope locally (Save/Recall menu)

2) Use an Ethernet cable to connect the PC and the oscilloscope

3) Open the browser and enter the oscilloscope IP (Chrome browser is recommended)

4) Click the File Browse tab

5) Right click on the target waveform file and save it as

Figure 4 Accessing oscilloscope storage files from a web page

Summarize

The ZDS4054 Plus oscilloscope has a large storage depth of 512M, and can record a maximum of 7.1 hours of waveforms at a time, which can be used flexibly to achieve the effect of a waveform recorder while performing real-time analysis. It should be noted that waveform acquisition will be interrupted during the export and save process. Due to the storage mechanism, the oscilloscope is currently unable to continuously and seamlessly acquire two 7.1-hour waveforms, which is a small pity, but its deep storage and waveform export functions make up for this defect to a certain extent. While achieving long-term waveform recording, combined with rolling measurement and remote control functions, it can also achieve the effect of remote long-term monitoring. Please pay attention to subsequent articles to learn more applications.

Figure 5 ZDS4054 Plus