Waveform history data problem

[ok@fine]

We all know that the historical data of the waveform chart can be cleared through the attribute node, but assigning an empty array to the attribute node will clear all the historical data. But I only want to clear part of the historical data. What should I do?

[RavensFan]

Write a waveform or array into the history property node that only includes the part of the data you want to keep.

[GerdW]

Hi guy from China,

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ok@fine wrote:

We all know that the historical data of the waveform chart can be cleared through the attribute node, but assigning an empty array to the attribute node will clear all the historical data.

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You use a property node to read/write the history of a chart.

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ok@fine wrote:

But I only want to clear part of the historical data. What should I do?

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Read the history, "clear part of it", write the history…

[ok@fine]

Thank you for your reply.For example, when daqmx collects data in real time, the waveform chart adopts the refresh mode of strip chart. At this time, the waveform will be continuously displayed. If the historical data of the waveform chart is cleared regularly, it will lead to the discontinuous display of the graph. How to solve this problem?

[RavensFan]

Which of us ever said to "clear it regularly"?

A chart has a history.  You said you want to eliminate part of the history.

Don't write an empty array to the history property node.  Write an array that contains the data you want to keep to the history property node.

How often do you plan on rewriting the history of the chart?  Why are you eliminating part of the history?

[ok@fine]

Thank you for your reply.I want to show the data on the waveform chart in real time. What should I do？

[GerdW]

Hi guy from China,

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ok@fine wrote:

Thank you for your reply.I want to show the data on the waveform chart in real time. What should I do？

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Just wire the data to the chart terminal.

Why do you want to fiddle with chart history?

(When you really need to change/edit that history data so often you really should be using a graph instead…)

[ok@fine]

Now we encounter the problem that too much historical data leads to the slow display of signals on the waveform chart, so we want to solve this problem by changing the historical data of the waveform diagram

[GerdW]

Hi guy from China,

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ok@fine wrote:

Now we encounter the problem that too much historical data leads to the slow display of signals on the waveform chart, so we want to solve this problem by changing the historical data of the waveform diagram

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Simple solution: change the history buffer size…

Again: when you need/want to edit the history data of a chart so often you really should be using a graph instead!

[ok@fine]

Thank you. I'll try the graph