How can i read data continually and display at a waveform graph

[meiyan]

I am doing a project that read data(incoming solar radiation) from a text file and display it  in a waveform graph.i need data be read continually ,but i only can show all the data at one time.

[Dennis_Knutson]

You have no loop so of course the file will only be read once. Why do you need to read it more than once, anyway? Is the data in the file changing?

[meiyan]

i know it should have one loop and a delay,but i dont know how to add the loop,because i need read no. that inside the file one by one ,so that the waveform can run as time goes by.

[Dennis_Knutson]

So, you did not answer my question about whether the file is changing. Let's assume it is so you will first have to monitor the file size and only read when new data is written? Try the code here.

[meiyan]

sorry..the file is already exist and wii not change .

[Dennis_Knutson]

Then all you want to do is simulate a point by point acquisition? If so just feed the array into a for loop and inside the for loop, have a chart (not a graph) with a wait function.

[meiyan]

still cannot...time is running ,but all the points still come out together

[Dennis_Knutson]

Post your modified program.

[Dennis_Knutson]

No. You should have simply used the Read From Spreadsheet function and wired the output of that through the for loop. As I said, inside the for loop would just be the chart and wait function.

You can set the chart's multiplier to 250 msec with a property node or from the front panel and select the chart's properties>Scale. See the example called Real Time Chart for how to do it programatically.