Com this is the common terminal of the relay. Common compact 35 mm pitch terminal block with color coding for easy identification and use.
Terminal And Station Maps
What is a common terminal. 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. 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. Com is the common connection for relay or transistor outputs. 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. If you want to make measurements you have to have reference points. L1 is the terminal to which the neutral core wire is attached the blue wire traditionally black before the change.
If the relay is powered and the switch is closed com and no have continuity. The faceplate of a single one way switch has two terminals. Some plcs have form c contacts which would have no com and nc normally closed contacts. It can refer to either a neutral wire or a wire that is connected to more than one other wire. The modular nature of these terminal blocks allows for the multiple branching of power between a device or devices. And often the neutral for a power system is considered its reference point.
Com or common is the terminal to which the live core wire is attached this is the brown wire formerly red. The term common can have two different meanings when it comes to electrical wiring. For example on a relay you would connect a common hot not neutral wire to a terminal. Nc this is the normally closed switch. Often the common terminal for the dmm is a reference point.
Gallery of What Is A Common Terminal
