PicoScope 7 Automotive
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Noise issues with scope operation!
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Technician
- TwoWaves
- Posts: 707
- Joined: Thu Apr 24, 2014 8:32 pm
Noise issues with scope operation!
As we know from previous discussions I have had noise issues with the PicoScope operation. With the kind help and support of the Pico staff, reference Steve Smith I changed the mains power supply unit that came with the PC because there was no filter built in. Immediately I noticed a 100% improvement with Pico Diagnostics operation, but I failed to recognise a noise issue when using Pico 6 software.
Each time I activated the scope channel A set on 'auto', I would notice significant noise present, so I just set the voltage scale each time to 20 V and that got rid of the noise, so I did not think anymore about it.
A member (New one) on here has recently posted regarding high voltage over range issues, well I also notice them and have read up on a previous post by Steve Smith regarding grounding of the channels. In my case I always stack the grounds from each channel so I'm not convinced the ground issue is the cause in my case. I have also used high voltage scales to try and work my way round the 'over range' issues, but when using voltage ranges of 50 V or more for sensors of 5 to 20 V I thinking something else is the cause but not sure what?
Having now been thinking about this issue because of the recent posts by the New Poster (member), and using my laptop at home, the scope is connected and I have switched on all four channels, with no BNC leads connected and each scale set to 'auto'. Looking at the graticule screen what appears interesting is that only channels B and C are producing any noise issues!
One other thing I have recently noticed with the scope is that having left the blue lead permanently connected to the laptop and scope, and then starting up the software, the scope 'red' LED on the front panels stops illuminating, although the four channels are live on the graticule screen! I'm a bit puzzled how the channels are all live but the scope appears disconnected!
Tomorrow I'm going to take the scope back to work and test it on the other PC as above and see how the channels operate regarding the noise issues.I'm not too concerned about the LED failing to illuminate so long as the scope keeps working, and I'm not convinced its a software issue as at home I'm now running the latest software, just not had time at work to update the other PC yet. I'm not convinced buying a new scope will cure the problems either as the New Poster I believe has only just recently bought his 4425 scope!
One other thing I've noticed while trying to upload attachments is that the poster cannot see the upload anymore and has not way of knowing if the attachment has uploaded, hence I have tried two or three times on this post and nothing has been uploaded!
Each time I activated the scope channel A set on 'auto', I would notice significant noise present, so I just set the voltage scale each time to 20 V and that got rid of the noise, so I did not think anymore about it.
A member (New one) on here has recently posted regarding high voltage over range issues, well I also notice them and have read up on a previous post by Steve Smith regarding grounding of the channels. In my case I always stack the grounds from each channel so I'm not convinced the ground issue is the cause in my case. I have also used high voltage scales to try and work my way round the 'over range' issues, but when using voltage ranges of 50 V or more for sensors of 5 to 20 V I thinking something else is the cause but not sure what?
Having now been thinking about this issue because of the recent posts by the New Poster (member), and using my laptop at home, the scope is connected and I have switched on all four channels, with no BNC leads connected and each scale set to 'auto'. Looking at the graticule screen what appears interesting is that only channels B and C are producing any noise issues!
One other thing I have recently noticed with the scope is that having left the blue lead permanently connected to the laptop and scope, and then starting up the software, the scope 'red' LED on the front panels stops illuminating, although the four channels are live on the graticule screen! I'm a bit puzzled how the channels are all live but the scope appears disconnected!
Tomorrow I'm going to take the scope back to work and test it on the other PC as above and see how the channels operate regarding the noise issues.I'm not too concerned about the LED failing to illuminate so long as the scope keeps working, and I'm not convinced its a software issue as at home I'm now running the latest software, just not had time at work to update the other PC yet. I'm not convinced buying a new scope will cure the problems either as the New Poster I believe has only just recently bought his 4425 scope!
One other thing I've noticed while trying to upload attachments is that the poster cannot see the upload anymore and has not way of knowing if the attachment has uploaded, hence I have tried two or three times on this post and nothing has been uploaded!
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Steve Smith
- Pico Staff Member
- Posts: 1586
- Joined: Sun Aug 25, 2013 7:22 am
Re: Noise issues with scope operation!
Hello and thank you for the post.
Just reading this through I must refer once again to the following post topic21251.html that will help with a description of noise and the tools at our display to deal with such environmental conditions.
With regards to stacking your test lead ground points this is perfect, but remember you have the option to use the sensor ground with the 4425 as described here: https://www.picoauto.com/library/training/filtering
The Hardware Filter (described in the filtering article above) will also help to control noise spikes once you have determined they are not relevant to your symptom.
Having your scope connected to the PC and running with all channels active at +- 50 mV range will allow you to capture ambient noise.
Once you connect a test lead to one of these active channels (leave 4 mm banana ends open) you have now created an antenna that becomes receptive to ambient noise which is clear to see on your display. There are times when you can use this technique to your advantage should you wish to measure the presence of an electrical field about a consumer (solenoids and injectors etc.)
If you have noise on active channels set to +- 50 mV without a test lead connected to the scope then we need to check the environment before assuming we have a concern with the scope.
One quick check you can do is to connect a test lead to your cope and join the 4 mm banana ends together. This should quench any noise assuming your environment is not subject to intense EMI.
Information on the status of your scope “Front Panel” LED’s can be found here:
https://www.picoauto.com/download/docum ... -guide.pdf
With regards to uploading attachments, could you help with the sequence of events leading up to the failure to upload?
Ideally screen shots of the process (which is a nuisance I know) but will help.
You can send your screen shots via email to support@picotech.com ref this post.
I hope this helps, take care……Steve
Just reading this through I must refer once again to the following post topic21251.html that will help with a description of noise and the tools at our display to deal with such environmental conditions.
With regards to stacking your test lead ground points this is perfect, but remember you have the option to use the sensor ground with the 4425 as described here: https://www.picoauto.com/library/training/filtering
The Hardware Filter (described in the filtering article above) will also help to control noise spikes once you have determined they are not relevant to your symptom.
Having your scope connected to the PC and running with all channels active at +- 50 mV range will allow you to capture ambient noise.
Once you connect a test lead to one of these active channels (leave 4 mm banana ends open) you have now created an antenna that becomes receptive to ambient noise which is clear to see on your display. There are times when you can use this technique to your advantage should you wish to measure the presence of an electrical field about a consumer (solenoids and injectors etc.)
If you have noise on active channels set to +- 50 mV without a test lead connected to the scope then we need to check the environment before assuming we have a concern with the scope.
One quick check you can do is to connect a test lead to your cope and join the 4 mm banana ends together. This should quench any noise assuming your environment is not subject to intense EMI.
Information on the status of your scope “Front Panel” LED’s can be found here:
https://www.picoauto.com/download/docum ... -guide.pdf
With regards to uploading attachments, could you help with the sequence of events leading up to the failure to upload?
Ideally screen shots of the process (which is a nuisance I know) but will help.
You can send your screen shots via email to support@picotech.com ref this post.
I hope this helps, take care……Steve
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Technician
- TwoWaves
- Posts: 707
- Joined: Thu Apr 24, 2014 8:32 pm
Re: Noise issues with scope operation!
Hello, thanks for replying to the thread Steve.
I have looked again at the noise issue and followed your instructions above to test for it. I have tried each channel individually this time to assess any outcomes. With no leads connected to the scope I get NO noise. With the leads connected to the BNC connectors and left in open circuit condition, I get noise as previously uploaded. Following your advise above when I connect the BNC leads ends together set on auto I still get noise on each channel at about the same voltages with each channel set on auto. I do also get the over range warning in red, it is intermittently displayed on/off when the BNC leads are shorted together.
Tomorrow afternoon I'll shut everything off in the garage and operate the scope again as above and see if I notice anything different to establish if the cause is EMI related or not. As for the attachments I'll sort a screenshot over the weekend and send it through for your reference.
Thanks
I have looked again at the noise issue and followed your instructions above to test for it. I have tried each channel individually this time to assess any outcomes. With no leads connected to the scope I get NO noise. With the leads connected to the BNC connectors and left in open circuit condition, I get noise as previously uploaded. Following your advise above when I connect the BNC leads ends together set on auto I still get noise on each channel at about the same voltages with each channel set on auto. I do also get the over range warning in red, it is intermittently displayed on/off when the BNC leads are shorted together.
Tomorrow afternoon I'll shut everything off in the garage and operate the scope again as above and see if I notice anything different to establish if the cause is EMI related or not. As for the attachments I'll sort a screenshot over the weekend and send it through for your reference.
Thanks