Test and Measurement Forum

PicoScope locks up machine when using trigger

Forum for discussing PicoScope (version 5)

PicoScope locks up machine when using trigger

Postby Rick Rae » Mon Feb 21, 2005 6:24 pm

I looked through the forums but didn't see anything that directly addresses this; sorry if I missed something.

Ages ago, I purchased an ADC-12 for a development project. It worked great! Recently I started a new project that called for its use again, so I dug it out. Couldn't put my hands on the original software quickly, so I downloaded and installed the current PicoLog and PicoScope on an HP/Compaq nx9010.

PicoLog works fine, as does PicoScope in MOST ways. However, I need to do a one-shot trigger and look at a transient waveform, and this is where I'm running into problems. If I try to start PicoScope in any triggered mode ("Stop," select Auto, Repeat, or Single, "Go"), the machine completely freezes as soon as I click "Go.". I mean completely -- I can't even CTRL-ALT-DEL, and have to power-cycle to get the machine back.

It's not a case of PicoScope watching for a trigger value and then all is okay; I've set the trigger threshold so low there's no way the scope couldn't have triggered -- no difference. It's completely locking up.

Any idea as to what's going on or what I can do to get this working? I really need to capture this data.

Thanks for any insight anyone can offer,
Rick
Rick Rae
 

Postby Sarah » Tue Feb 22, 2005 10:22 am

Hi Rick

Thank you for your post.

What you are seeing is due to the computer devoting all of it's energy to looking for the trigger signal. It therefore willnot see any other commands incase it misses it while dealing with the other commands. It has to do this because the ADC-12 has no internal memory.

To get it to come to life again you need to cause the trigger to happen. If you are using single trigger then once you have caused the trigger to happen it should return to normal as it will stop. However if using repaet it resets itself and so you need to press the space bar BEFORE causing the trigger to happen.

This way the command to stop is in a queue and as soon as the trigger has occured the computer will look at this command and follow it through.

Hope this helps

Best Regards
Sarah
 

Postby Rick Rae » Wed Feb 23, 2005 1:13 am

Sarah wrote:What you are seeing is due to the computer devoting all of it's energy to looking for the trigger signal. It therefore willnot see any other commands incase it misses it while dealing with the other commands...

To get it to come to life again you need to cause the trigger to happen. If you are using single trigger then once you have caused the trigger to happen it should return to normal as it will stop. However if using repaet it resets itself and so you need to press the space bar BEFORE causing the trigger to happen.

Hello, Sarah. Thank you for responding, but it seems you missed part of my post. I stated:

It's not a case of PicoScope watching for a trigger value and then all is okay; I've set the trigger threshold so low there's no way the scope couldn't have triggered -- no difference. It's completely locking up.

Nor is it a single versus repeat trigger issue; a trace doesn't even appear, ever. It absolutely and completely locks up the entire system.

I do need to correct one statement; I said that it would lock up in any trigger mode. On further investigation I found that it will trigger in "auto" mode, however during one test the computer still locked up in "auto" after a few dozen sweeps. And, unfortunately, "auto" doesn't help with my need to capture a one-shot event.

Rick
Rick Rae
 

Postby Sarah » Wed Feb 23, 2005 10:07 am

Hi Rick

Thank you for your post.

I still believe that this problem is caused by the computer devoting it's energy to looking for the trigger, however I am not sure why the trigger should not be occurring.

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. 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?

Also, what version of Picoscope do you have?

Best Regards
Sarah
 

Postby Rick Rae » Thu Feb 24, 2005 12:44 am

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. :D

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.

Cheers,
Rick
Rick Rae
 

Postby Sarah » Thu Feb 24, 2005 10:09 am

Hi Rick

Thank you for your post and the extra information.

Firstly, what you mention about the "erasing trace" is a software bug that we are fixing at the moment. The next version of Picoscope that we will release should contain this fix.

Let me know how you get on with your signal generator. If after some more experiments you believe you unit to be broken then we will be more than willing to have a look at it, however a repair is chargable if the unit is outside of the warranty period. As you have since managed to get the unit to trigger I suspect that it is not faulty.

Hope this helps

Best Regards
Sarah
 

Postby Rick Rae » Fri Feb 25, 2005 12:18 am

Sarah,

Unless your warranty is about a decade long, I'm pretty sure this one's out. :) I don't remember when I bought it but it was WAY back.

I'll let you know if I discover anything interesting in my tests, and will keep an eye open for the bugfix release of PicoScope.

Thanks,
Rick
Rick Rae
 

Postby Doug Shearer » Tue Mar 08, 2005 8:34 pm

I have a similar problem.

When using the trigger, the display does not freeze completly but the mouse pointer moves in jerks and the PC becomes unusable.

Is this the same problem?
Doug Shearer
 

Postby Sarah » Wed Mar 09, 2005 11:10 am

Hi Doug

Thank you for your post.

Which unit are you using?

Best Regards
Sarah
 

Postby Guest » Mon Mar 28, 2005 10:32 am

Sarah
Sorry for delay in responding. I use Picoscope (and there isn't anything else in our price range that does the job - it's really useful for frequency meter etc etc! in fits and starts for A level teaching in the Advancing Physics course.

We have an ADC-100.

Could be something to do with sample rates/refresh etc which I don't really understand.
I have read your other posts about the PC looking for a trigger signal but I feel the trigger is present, not too short and of a good amplitude.

What I want to do is trigger the scope at a particular level to maintain a steady trace on the screen and lock one signal to compare the other channel with it.

In the past I have also had problems displaying a voice trace and wonder if it's possible that this is a linked problem (or what settings should be made to enable me to do this)

Sorry if this is two problems in one...

Thanks
Doug
Guest
 

Postby Sarah » Tue Mar 29, 2005 10:53 am

Hi Doug

Thank you for the extra info.

Does this behaviour present when you use the unit on different PCs? If you try slowly increasing the signal level, will it then trigger?

I have been looking at ways around this problem and have found that if you use the ADC-100 in conjunction with our USB to Parallel port adaptor, it does not freeze while waiting for the trigger.

With voice traces you need to ensure that they are amplified suficiently. Check that it is giving a good output into the unit, if it is too low then the unit won't be able to see it.

Hope this helps

Best Regards
Sarah
 

Postby Guest » Tue Mar 29, 2005 11:12 am

Sarah
Thanks.
I will have to try this the next time I use it.
I think it happens on our old Win 98 laptop and my XP Pro laptop.

If the USB adaptor is a fix - how much is it?
Guest
 

Postby Sarah » Wed Mar 30, 2005 9:04 am

Hi

Thank you for your post.

The USB to Parallel adaptor is £50 plus tax and delivery. Please note that only our adaptors will work with our units.

Let me know how you get on.

Best Regards
Sarah
 

PC locking up

Postby Robert Tait » Wed May 24, 2006 3:55 am

Hi' I have been using an ADC 11 with Picolog for some time now.
The ADC 11 is a parallel port version, the PC is running XP professional.

I am using the ADC 11 to log battery discharge voltages over time eg 1 hour at 30second intervals.

Generally Picolog works well but ocassionally the program will freeze and as mentioned by other people powering off the PC is the only way to get it back up and running.
When the PC freezes its at the end of a test.( after completion of No of samples eg 500)
Another strange thing that also only occasionally happen is I click on the Pico recorder Icon but pico Player opens.
Reboot PC click on the pico recorder Icon and recorder opens.

I am currently running SW version R5.12.x.


I originally thought it was a PC problem but have changed to another PC and the problem still exists.
Uninstalling and reinstalling the software doesn't seem to help.

Any suggestions?

Regards
Robert Tait
Robert Tait
 

Postby Sarah » Wed May 24, 2006 2:29 pm

Hi Robert

Have you tried the latest version - 5.13.9?

The issue with the player opening means that psw32.exe is still running in the background and hasn't exited properly. You need to end the task from the task manager and also make sure you disconnect all Pico USB devices for it to work. This will be the same if the program crashes - all USB devices need to be disconnected for it to exit correctly.

Let me know how you get on with the latest software.

Best Regards
Sarah
 


Return to PicoScope 5

Who is online

Users browsing this forum: No registered users and 0 guests