Sure, first you need a place to put the captured data, usually a global variable:
then you need to determine when you want to capture the data. The easiest way is from a button, but you could have automatic capture based on inputs by using a channel event. The concepts are similar. You also need to decide how much data to capture. Lets say you want to capture 0.5 seconds worth of data on button press:
1) create a button, go to the Action tab and select Quick Sequence
2) put this script in:
captureddata = mychan[systime(),systime()-0.5]
Now, whenever you click the button, the captureddata variable will get the last 0.5 seconds of data. This is done by subsetting by time instead of index. If you wanted the last 100 data points, you'd do:
captureddata = mychan[0,99]
Once you have the data captured, you can plot that variable on a trend graph, or do calcs, for example, the max:
which you can display in a variable value component.
I've attached a sample to get you started.