Hello, I am new to this forum. Do input cards like <AB 1394 discrete input> carry current in the input signal wire? For example, if you have a limit switch, at one end is the 24V DC supply, and the other end is connected to the input card. When the swtich is closed, does current (and how much?) actually flow through the wire, and the input card sees "ah, 24V, I see signal"? I'm not sure if the input cards act like volt meter - they just sense voltage? Is there actually any current flow? I tried the data sheets, but I couldn't find much. Thanks, Eric