Reduce the graph speed without changing the xscale

[Neuropotential]

Hello Experts,

I have a program which continously acquires analog data from DAQ card at 5 kHz. I am plotting the 2 channels on the waveform chart in strip chart mode. 

I would like to have the speed of the waveform reduced when the xscale is around 2s. When the xscale is around 5-6s, the speed of the waveform is correct for me. I am decreasing the xscale to 2s, so that I get better time resolution and I am able to see much better. When I use xscale of 2s, the graph updates too fast and I can hardly see anything. 

Is there any way to decrease the speed without compromising on the real time data acquisition?

[jcarmody]

Make your chart reaaaaaaaaly wide! 😉

[Neuropotential]

I tried that before but it is still fast!! Any other alternative?

[battler.]

Remove your Graph updating (control) from the acquisition loop, that way you can choose the frequency of updating the graph independent of anything else.  Make another parallel loop (producer/consumer architecture) for your graph updating.

Store the graph data from the acquisition loop in an array using a shift register.  When you want to update the graph (i.e. at what frequency - could be after so many data point acquisitions - size of array) send the data to the graph loop (using queue). 

Message Edited by battler. on 05-08-2010 07:47 PM

[Neuropotential]

I will try that.