Data points of Waveform Chart Time Axis after Range Change

[Nustian]

Hi

I am using LV2017 for developing an application that plots real time data on a waveform chart. The data is acquired after 1s, as I kept history length buffer at 1024 and multiplier at 1, the time axis shows data for seventeen minutes before scrolling. Now the requirement is that user should be able to make runtime change(increase/decrease) to the time axis range e.g  data for six hours should be visible. I can modify the time range displayed on x-axis by tinkering with the multiplier but no idea how to match number of data points with total number of seconds. A post suggested history length but as the history length cannot be changed programatically,  kindly suggest a solution. The data is fed into chart as an array, using a waveform datatype is not an option.  

thanks

[GerdW]

Hi Nustian,

---

@Nustian wrote:

A post suggested history length but as the history length cannot be changed programatically,  kindly suggest a solution. The data is fed into chart as an array, using a waveform datatype is not an option.

---

When you want to fully control the displayed data you should use a graph instead of a chart…

Why is there no option to use waveforms?

[Nustian]

@GerdW

Is there any option with waveform charts?

[GerdW]

Hi Nustian,

---

@Nustian wrote:

Is there any option with waveform charts?

---

Charts have a fixed-sized history (at runtime).

To simulate a variable-sized history you need to decimate your data to account for those x-range changes: when the x-range is doubled then the data is decimated by a factor of 2 (and the x-scale multiplier is doubled to account for changed dt). This will be a lot of work with lot of chart property node accesses: using a graph instead will be easier IMHO.

[Nustian]

Hi

Can you attach an example vi.

Thanks

[GerdW]

Hi Nustian,

no, I will not setup a working example for this stuff using a waveform chart: I still prefer graphs…

[Nustian]

---

@GerdW wrote:

Why is there no option to use waveforms?

---

The waveform chart has more than 100 plots (data received after every 1s)  with 5-8 plots visible at one time.