graph and samples

[BjarneDK]

Hm ok I will try to attach my program and the error. I tried to build what you did, at one of the graphs but I cant find the history property node 😞 Well this program is basically able to collect two pressures, one flow, one trigger signal and 6 forces from a SCXI module. When I use collector it craches when I try to save.. See error message, I hope it make sense..

[NIquist]

You can create a property node by right-clicking on a block diagram icon (or front panel control) and then create>Property Node>History Data (or whatever parameter you want).  [FYI:This will be an implicit property node meaning it's linked "under the hood" to the control or indicator.   You can also explicitly link a property node pulled off the palette by directly wiring a reference to it.]

I still can't open your VI but the error message is a classic DAQ timing issue.  You have set parameters that are causing samples to be leftover in the DAQ card buffer when the card is asked to collect again (which will overwrite the buffer).  Something is set too fast OR you are not buffering out your data correctly.  Hopefully someone can look at your code and give you some more help.

[BjarneDK]

Thanks, i found the node, somehow I missed it yesterday 🙂 But anyway I tried it out and it might seems to work, am i right with the example, that it is in sec (2sec) the last one?

If this is right, is it then "ok programming" to make a hidden chart and then convert it, like in the example?

[NIquist]

Your math is correct and this will technically work.  I wouldn't call it "OK programming" though.  It's probably worse than building an array in a loop as far as efficiency goes.  The chart and its history property node have no data flow so you could lose data on the last iteration.  I'm sure there are more issues I can't see right now.  Again, I thought you needed a way to pull data from a chart and make its timebase correct.  If your application is to monitor timebased signals accurately on-the-fly then you should avoid the chart and use a better method for viewing and storing the DAQ data.

I can't provide much more without being able to open your VIs.  If I find some general examples, I'll post them up.

[BjarneDK]

Ok, thanks. I just ran my program and it also seems to run the graphs slow and only show one curve (I have more than one in each graph). Hm I have to try something else.

[BjarneDK]

Hi anyone..

If i wanna stick to the chart is it then possible to "convert" x-axis into a timeline? I tried to convert the number of samples, but I think that its wrong to multiply. Is there any chance that its possible to get the chart to show fx 2sec, like the above graph, or should I forget about the chart?

The graph in the middle seems to add the signals, and that is not the purpose.

I dont get it 🙂

[BjarneDK]

By the way I tried to build a waveform for it, as suggested, but couldnt get t0 to work right, as a 0-2 sec line (maybe I did something wrong?)