graphing against systime()

[Lockie]

Hi 

I am trying to create a graph that begins at zero at a zero time stamp.  However when I change the graph x expression (in graph properties) from "time" to anything referencing "systime()" the trace disappears.

My approach was to use the start time from a button that runs the below code:

global expStartTime1 = systime() // Test Phase Timer
global expStopTime1 = 0
global GraphTime = Time()

and create a graph using the x expression "systime()-expStartTime1" (with bottom axis set to time and date).  I have tried heaps of things but it appears that when systime() is used I lose the data?

Any help would be really appreciated.

 

[AzeoTech]

You have the right idea, but the problem is that systime() - expStartTime1 is a scalar and you can't plot a single data point.  You need an array of times, and the best place for that is in your Y data.  So if your Y Expression is "MyChannel", your X expression would be "MyChannel.time - expStartTime1".