If the relay is powered and the switch is closed com and no have continuity. Essentially when the output is activated the plc will energize the relay or transistor effectively connecting the no normally open pin to the com common pin.
No C Common Terminal On Furnace Home Improvement Stack
What is a common terminal. For example on a relay you would connect a common hot not neutral wire to a terminal. Com or common is the terminal to which the live core wire is attached this is the brown wire formerly red. L1 is the terminal to which the neutral core wire is attached the blue wire traditionally black before the change. The modular nature of these terminal blocks allows for the multiple branching of power between a device or devices. It can refer to either a neutral wire or a wire that is connected to more than one other wire. And often the neutral for a power system is considered its reference point.
Com this is the common terminal of the relay. Nc this is the normally closed switch. Com is the common connection for relay or transistor outputs. If you want to make measurements you have to have reference points. Then depending on whether power is applied to the coil or not the power on the common wire goes through the relay to the load or doesnt if it is connected to a set of normally closed contacts. The faceplate of a single one way switch has two terminals.
This is the terminal where you connect the device that you want to power if you want the device to be on normally when the relay isnt powered and off when the relay is powered. Common compact 35 mm pitch terminal block with color coding for easy identification and use. Often the common terminal for the dmm is a reference point. Some plcs have form c contacts which would have no com and nc normally closed contacts. The term common can have two different meanings when it comes to electrical wiring.
Gallery of What Is A Common Terminal
