Floating ground

Electronegativity

Hi, I'm looking at the schematic diagram of the Super Carrier Board:

It looks like VSS is identical to ground, but the board itself is "floating in space".
There is no true ground.

For a mobile application it may not be possible to provide a true path to ground; is this a problem?

-Alexander

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I wonder if this wire is hot...

Chris Savage

Alexander,

·· Vss is equivalent to Ground.· I can't tell from your post if your mobile application is a vehicle or not.· If it is, getting power to it will require 2 conductors, and one will be ground.· Therefore you will have a common ground.· Either way, if you plan to control anything in the mobile application that is not isolated, either mechanically (i.e. relay) or optically (optocoupler) then you will need a common ground.


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Chris Savage
Parallax Tech Support
csavage@parallax.com

allanlane5

If by a "true path to ground" you mean a wire sticking into the dirt, then no, you can't have that.

If by a "true path to ground" you mean a connection to a car's Ground rail, then yes, that's the common ground Chris is referring to.

In any event, as long as all the stuff inside an enclosure is sharing the same ground, it doesn't really matter if it is a "true ground".

Ryan Clarke

Keep in mind that 'ground' is a relative level, not an absolute- that's why we have the term 'common ground' -

You can (in a simple form) think of ground the same way you think of relative velocity- To a guy standing on the side of the road, a car going 50mph is moving pretty fast, but to a motorcycle going 40mph in the same direction the car is only going 10mph (from the motorcycle frame of reference)-

Ryan