"Be Aware of Dog" sign?

I was thinking of putting up a beware of dog sign on my property. He's not agressive per say but if I was in danger I know he would attack a criminal. The only reason I would put it up is so if someone breaks into my house I don't want then suing me or getting my dog put down for defending me. So does putting up one of those signs make me legally unresponsible for what happens to them if they break into my home? Kind of like how the law says you have to fire a warning shot first. Only the warning shot is the sign and the actual consequence is my dog protecting me.

I'm sorry if it sounds stupid. I'm just curious. And I live in a bad neighborhood so I need to know my dog can protect me if need be without the threat of being put down.