How to extend the run time on a graph

[lanvle]

Hi All,

I have a VI that captures data from a DAQ. The VI plots the data on a graph (front panel) and saves the measurement data on a lvm file. The lenght of the run time is controlled by the program. The measurment data works for the specified controlled time but the graph stops updating data when it supposed to update more data on the graph, e.g. time = like 40800 seconds (<specified runtime).

It seems the buffer of the graphs is set/limited to a certain number.

How do I extend the run time on the  graphs.

Thanks,

Lan

[Dennis_Knutson]

A waveform graph has no buffer. It displays whatever is passed to it and is limited by the amount of memory in your pc. A waveform chart has a buffer defined by the history length (right click on a chart to view/set it) but when the history length is reached, it discards old data and updates with the new data. Neither type stops updating. So, what you are seeing is something else. Perhaps you have turned autoscale off? Are you trying to keep all data for such a long run in memory? If that's the case, what you might be seeing is simply a slow down due to memory problems. How much data does that run time equate to. In other words, what is the sample rate, how many samples do you request, and how often do you call the acquisition VI?

[scottcolston]

if you have to use a graph rather than a chart you can use the build array function ans shift register to continously update the data displayed on the graph