Sarah wrote:If you try using a different, slower event to trigger the unit does this help? It may be that the trigger is being missed because it happens to quickly.
It would be difficult to get much slower.
I'm trying to capture the equivalent of an impulse from a plucked string. The fundamental is well below 60Hz. It's a nice, fat, slow pseudo-sine wave at that point. There's no reason it should be missed.
If you input a voltage which you slowly increase, or put in a voltage that is clearly more than the trigger value and then wait, does this trigger?
As a test, I connected a variable-voltage power supply to my ADC-12 via a 1x scope probe, picked a relatively slow 1ms/div sweep, and set the trigger to single-shot at 2.5v, rising edge.
The results surprised me, because I didn't expect it to work: When I raised the input voltage slowly, PicoScope triggered and released the computer just as it should have! (Wow, that was a first!) However,
in three of the tries I made, it also did something quite strange: As I crossed the trigger threshold, PicoScope would trigger and sweep (once), then the display would blank as if had not yet received a trigger (and the GO/STOP button still indicated it was waiting). This happened at a "moderately slow" rate of increase -- if I go agonizingly slowly, it always triggers, and it also always triggers if I turn the voltage up very rapidly ("rapidly" relative to how quicky human fingers can turn a knob, anyway).
If this is happening at some particular rate of change and my waveform just happened to cross the threshold at that rate for the most part, maybe it would appear to never trigger, and this is what was happening? That seems far-fetched, but it's the only thing that comes to mind. At any rate, this doesn't seem like correct behavior.
Any idea what might be going on, or any other tests you'd like me to run? I'll try to drag out the function generator and play with some other waveforms (faster and slower than the one I'm trying to capture) towards the weekend.
It would be so
bizarre if my specific waveform just happened
to fall within some narrow window where the triggering doesn't work properly. Not that it would surprise me, of course... I'm quite aware that Murphy is alive and well.
Also, what version of Picoscope do you have?
As I said in my original post, I downloaded and installed the current release. Help>About
says Release 5.12.0 - 32 bit with ADC12/etc. driver V3.1, pico.sys V2.0.