[erkiwi]

Hi,I am wiring up my limit switches and one end needs to be connected to 0 volts.Is this the same as ground,also on my breakout board I have a com connection is this also 0 volts?
Eric

[Karl_T]

No, not really. You have to be careful how you handle DC common or you get ground loops and weird sh*t happening.

I run all DC commons to a terminal strip where everything is connected together. Then one and only one connection from this to ground. Special note: keep this separate from the AC nuetral.

Al-the-Man posted a nice articlle on this subject a while back.

Karl

P.S. 0 volt and DC common are two ways to say the same thing

[Al_The_Man]

Unfortunately the makers or BOB's etc, often use the term Ground, when they mean Common, which may or not, be grounded.
Too bad, To the new comer to the electronic side, it can get confusing or misleading.
Al.

[TOTALLYRC]

Unfortunately the makers or BOB's etc, often use the term Ground, when they mean Common, which may or not, be grounded.
Too bad, To the new comer to the electronic side, it can get confusing or misleading.
Al.

I find it really gets confusing when they mention +12v and -12v and they don't mean switch the wires around.

Ground and Common get used interchangably when they may or may not be the same thing.

[Al_The_Man]

I find it really gets confusing when they mention +12v and -12v and they don't mean switch the wires around.

Yeah, That gets a bit misleading, what that means is, you have changed the reference point.
Unless it refers to -12v supply WRT to the COMMON reference
Al.