When to ground the Picoscope itself

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Jnaimoli
Newbie
Posts: 5
Joined: Wed Jun 10, 2020 5:31 pm

When to ground the Picoscope itself

Post by Jnaimoli »

Good morning from a cold snowy Northeast US. As the subject states, I would just like to confirm when I should be using the case ground on the pico itself. 4425A. Thanks in advance all

Steve Smith
Pico Staff Member
Pico Staff Member
Posts: 1311
Joined: Sun Aug 25, 2013 7:22 am

Re: When to ground the Picoscope itself

Post by Steve Smith »

Hello and thank you for the post

The following forum post will help with regards to removing noise via the USB cable using the ground point at the rear of the scope
viewtopic.php?p=95821#p95821

The following forum post will also help highlighting “Common Mode Range Error” warning and how grounding the rear of the scope will help
viewtopic.php?p=72231#p72231

In general, the need to ground the rear of the scope should be very seldom indeed

I hope this helps, take care……Steve

Jnaimoli
Newbie
Posts: 5
Joined: Wed Jun 10, 2020 5:31 pm

Re: When to ground the Picoscope itself

Post by Jnaimoli »

Thank you very much for the reply and info

martinr
TwoWaves
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Posts: 51
Joined: Tue Mar 06, 2018 4:06 pm

Re: When to ground the Picoscope itself

Post by martinr »

Reading your excellent question and Steve’s equally excellent reply, made me try to remember the couple of times that I have grounded my ’scope. Thankfully, I documented it in emails to Steve.

I made myself a grounding/earthing cable. I’m not familiar with US mains plugs because I live in the UK, but I presume you could do something similar. I removed the 2 phase pins from a mins plug so that I was left with just the ground/earth pin. I then wired a long green-and-yellow cable to it, on the other end of which is a crocodile/alligator clip, which can attach to the ‘scope.

I very rarely use it. In fact, I use it so rarely that I tend to be very slow to remember that grounding the ‘scope is a valuable option, especially when troubleshooting strange effects.

So I’ll try grounding the ‘scope if I’m seeing any strange anomaly, especially if it coincides with mains frequency. And especially if I have a device plugged into the mains, such as a laptop charger or a separate mains-powered monitor plugged into my laptop (which has necessitated grounding that monitor rather than the ‘scope).

Very occasionally I’ll wonder if I should ground my ‘scope as a matter of routine, especially if my laptop is running off mains power. That way, if I do notice anything strange, I wouldn’t be wasting an hour before I remember to see if grounding the ‘scope solves the problem. However, such events seem rare, and it’s one cable less to fall over.

I’m grateful you raised the question because it’s prompted me to read the links in Steve’s reply.

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