Posted by Tom Roberts on March 24, 2003 at 20:48:18:
The Picoscope default number of samples is disappointing in some circumstances. The default is 2500 maximum samples. In order to get the highest sample rates you will have to change this. Just go to 'Settings' 'Options' 'Advanced'. You will see dilaog boxes as shown here. Where it says 'Maximum samples per scope trace' you can enter any number from 500 to 32,000. Higher numbers result in much more detail especially when zooming in. More samples mean more dots and a more accurate representation of the action. More samples per trace naturally slow down the screen update rate.
To maintain the sample rate at time bases of 100ms/div or longer you need to select 'Block mode' here also. In the other modes, at 100ms/div or longer, the sample rate will be only 1000s/sec. I use 'Block mode' all the time unless I want to look at an O2 sensor scroll accross the screen then I use 'Chart recorder' You don't need a high sample rate then. In fact, it can pick ip too much noise and be a problem. Chart recorder continuously collects and sisplays data. Block mode collects a block of data then sends it to the PC.
So, for best results collecting a second of cam and crank relationship from a Chrysler 3.3, for example, the desired setting would be 32,000 samples in Block mode.
Hope you all find this useful. Play with it, you'll see.