Relation between X-scale multiplier, Chart history length with loop delay

[pbpatel]

Dear Sir,

I want to know the relation between X-Scale parameters like X-scale multiplier and chart history length.

[AdnanZ]

You need to be more specific with your question. What exactly are you trying to do and why do you need to know about this?

From LabVIEW Help: for a waveform chart, the offset and multiplier are used to specify the value of a scale marker and to display the marker in a convenient manner.For example, if you want the scale to display in milliseconds starting at a reference time, set Offset to the reference time and Multiplier to 0.001. If you change Offset, the scale no longer uses 0 as the origin of the plot. The relation between the multilplier and the chart history length depends on what you are displaying on the chart itself.

[altenbach]

The chart history determines how many x-axis points are kept in the history buffer.

The x-scale multiplier determines the increment between points.

They are independent, so there is no "relation". 😉

[pbpatel · Accepted solution]

Thanx for reply,

I want to know multiplier. My loop is running at 10ms rate and i want to display chart, lenth of 1 hr on screen.

[altenbach]

The multiplier just sets the scale, which is just cosmetic. You should set the multiplier to 0.01 if you want to display the x-axis in units of seconds.

As mentioned, the history lenght determines how many points are kept in history, so in order to display 1 hour worth of data at 10ms increments, the history length needs to be at least 100x60x60=360000. (Of course you can also set it longer but still only display 1 hour worth).