Detailed discussion of the ROLL mode of each oscilloscope

　　Through group communication, some customers expressed some doubts about the scroll mode of the ZDS2022 oscilloscope, so they had various questions and answers with our R&D colleagues. Next, we will share it with everyone.

　　The story begins with one-click ROLL switch

　　The ZDS2022 oscilloscope has seven "one-key operation" functions: one-key persistence, one-key cursor, one-key storage, one-key capture, one-key clear, one-key zoom and one-key scroll.

　　Figure 1 Distribution of 7 “one-key operations”

　　One-touch [ROLL] can switch the oscilloscope from YT mode to roll mode, which is very convenient. No matter in which mode, as long as the horizontal time base is less than 100ms/div, the oscilloscope will automatically switch to 100ms/div. In ROLL mode, the horizontal time base is not less than 100ms/div, and the maximum is 50s/div. Press the [ROLL] key again to switch to the YT mode.

　　In YT mode, when the horizontal time base is greater than 100ms/div, the waveform seems to be in "rolling" mode, but the waveform is displayed moving slowly from left to right, and they belong to different time base categories.

　　Comparison of ROLL mode mechanism between ZDS2022 oscilloscope and other brands of oscilloscopes

　　Some users mentioned the Tek oscilloscope and told us that the ZDS2022 oscilloscope seems to have a different ROLL mode than the Tek oscilloscope. The user is right, let's take a look at the ZDS2022 and Tek oscilloscope roll mode, what is going on?

　　Since I only have MSO4054, I will use it for experiment. As the horizontal time base increases, we can see from the upper left corner of the screen that when the horizontal time base changes to 40ms/div, the oscilloscope changes from running to scrolling. That is to say, the scrolling mode of the Tek oscilloscope is automatically switched into as the horizontal time base increases, and the critical horizontal time base is 40ms/div. When the horizontal time base decreases, it will automatically exit the scrolling mode and enter the YT mode. If you want to trigger a signal in the large time base mode, that is, you must be in the Normal mode, let's see how many steps are required for the Tek oscilloscope? It takes 3 steps! The ZDS2022 only needs one button to switch modes!

　　In fact, the use of the roll mode of the Tek oscilloscope is conditional. When switching to the envelope or average acquisition mode, when the horizontal time base increases to the point where it can be switched to the roll mode, the mode will automatically switch to the sampling mode. Moreover, in the Normal mode, the roll mode is also disabled. The ZDS2022 oscilloscope can be switched to the roll mode with one click in any other situation except in the XY mode. Of course, the XY mode of the Tek oscilloscope cannot be switched to the ROLL mode.

　　Climax

　　At this point in the discussion, some users reported that the waveform display of the ZDS2022 oscilloscope is a bit slow compared to the Tek oscilloscope under a large time base. For example, when the horizontal time base is set to 200ms/div, the ZDS2022 is in the commonly used YT mode, while the Tek oscilloscope has automatically switched to the scroll mode. They are not in the same mode environment, so the comparison is meaningless. In addition, the ZDS2022 has 14 horizontal grids, while the Tek has 10 horizontal grids.

　　Let's take a look at an Agilent oscilloscope. Where can you set the roll mode? One reason is that you are not familiar with the operation of the oscilloscope. However, even if you are familiar with the operation, it still requires complicated steps. Exiting the roll mode also requires repeating the steps of opening the roll mode, which is very cumbersome. The ZDS2022 oscilloscope's ROLL mode allows you to switch modes with just a light touch.