Hey guys i'm on a project in which I have to use Safety Modules.
I'm confused with the pin-out diagram of the safety modules. They reference L and N lines of an AC source. I'm leaving you the data-sheets of two different Safety Modules, both make reference to L and N lines.
http://www.pizzato.com/PizzatoWeb/UserFiles/File/pdf/ZE_GCS01A15/ZE_GCS01A15-ENG_183-206.pdf (page 2)
The safety Modules should go inside a machine in which the polarity (hot-neutral/L-N) is unknown. What does this mean, or what should I do to use them if I don't know what L and N are?