How would we wire the limit switch?, when we open it there are 4 terminals to connect to.
The four terminals are labeled. The upper two are Normally Open, meaning they will be closed when the switch is activated. The lower two are Normally Closed, meaning they will open when the switch is activated.
Is there apoint of having 2 Normally Open? wouldn’t it work with just using 1 normal opena nd one normally closed? or maybe even just using one of the terminals?
You get two connections, one on each side of the switch. How would you manage to use a switch that had only a terminal for a single wire? 
LOl alright thanks!
Dark,
There are certain designs that want two independent switches. Usually these designs take advantage of a timing difference between the contacts. Commonly known as make before break or make after break. This device also has replacable switch modules as listed on a few sites where it is available.