How to display waveforms as double precision versus seconds in a chart?

[RPJ]

I need some help with the following:

I am acquiring several waveforms that I display in charts. I would like to have an option to view data only when I press a button; I would like the new data coming in to append dirrectly to the old data displayed. If I do this with a waveform I cannot append to the old waveform displayed because the points coming is have the time information that will create a gap between old wave and new wave. In simple words is like this: when I turn onn a button data is flowing in my charts until I turn off the button; when I turn on the button again after a time t, the data will flow again on the screen but I will have a gap betweeen the old waveand the new wave of data. The gap is equal with t on the X-axis which displays the time elapsed.

Question is how can I do such that when I turn the button again the data starts to flow at the point where I left it and not after time t?

The problem might be saved by getting y from the waveform and displaying it in a chart? How would I set the X-axis to show me "y" (data) versus seconds?

Anybody has some advice and/or example?

Thank you

[jasonhill]

If you use the Append Waveforms function on the Analog Waveforms palette, the second wavform will be added directly to the end of the first without gaps.

[RPJ]

It looks I did not make myself clear. It is the same "pipe" I am using, the same waveform, only I want to display (and save) only parts of it when I turn a button on. If I would keep the button "ON" all the time the data would just flow in the chart and would be saved; BUT, I want to see and record only certain segments and I would like these segments to be displayed one after another without any gap between them.

So it is the same waveform from the same acquisition channel; I do not really want to append two different waveforms from different channels for example.

I do not really need the t0 information in the waveform so I was wondering if there would be a way to take only the Y and maybe dt information such that what I wrote above works...

Thanks

[jasonhill]

With a bit of wiggling, it can be done.  I don't know where your waveform is coming from, so I just used a generic control.  I then tack on the data when the "Aquire" button is on.  When the button is off, the shift register is just passed straight through. 



Note, this saves at the end.  You will need something different if you want incremental saves.

Another note, this will also totally destroy your timestamps... I don't think there is anyway around that.

Message Edited by jasonhill on 02-23-2006 01:51 PM

[RPJ]

It's not working for my case. Sorry...

The waveform that is coming in is the voltage from a power sensor - see the power chart in the attached picture. The second picture shows the gap in the power waveform.

[jasonhill]

Its hard to find the space to run wires all the way to the while loop boundary on these sorts of large block diagrams.  It is a little easier to read when you use a feedback node.  Do not forget to have an empty waveform with the correct dt plugged into the initializer terminal.  I don't see anything on the block diagram that would preclude you from using this method.




There is an "Ignore waveform time stamp on x-axes" setting in the chart properties.  I have never played with it, perhaps it will do what you wish...

Message Edited by jasonhill on 02-23-2006 03:38 PM

[RPJ]

I tried just connecting a wire from outside the loop and did not work. That is, I do not get what I want. I will try and see what "Ignore waveform time stamp on x-axes" can do...

Thank you.