3 Wire Sensor Connection To Plc

Note the each of these sensors has three wires.

3 wire sensor connection to plc. The brown wire is the vdc wire that connects to the positive side of the power supply and the blue wire is connected to the common terminal of the power supply. Normally open or normally closed sensor logic does not affect physical connections between a sensor and a plc. The difference is that the 3 wire device has a supply source supply common and signal output. Knowing how to connect a 3 wire dc solid state proximity sensor to a plc programmable logic controller is dependent on the type of proximity sensor and the plc to be used that is specific to the design of the circuit and the preferred application.

In the diagrams below for a pnp sourcing field device the supply common is connected to the field device common. Pnp switched positive npn switched negative switched refers to which side of the controlled load relay small indicator plc input is being switched electrically. There are two basic types of 3 wire proximity sensor applicable to certain types of plc. Sensors with 3 and 4 wires have dedicated output wires.

This is the negative terminal that is present on the power supply. A 3 wire sensor typically is color coded with one brown wire one blue wire and one black wire. To review we have learned that there are many types of discrete 2 wire dc sensors that can be wired to a plc input. The 4 20ma analogue signal is by far the most commonly used in industrial applications.

In this simplified diagram of an inductive switch there are three wires. If we connect the photoelectric switch to plc input channel 3 the red wire will be connected to 24vdc and the black wire will be connected to terminal d. These output wires are run straight to a module s input. Additional component connections to plc include the following.

Sourcing plc input module three wire devices work in the same manner. Here s a quick way to wire npn and pnp devices wiring npn sensor to plc video wiring pnp sensor to plc video wiring contact discrete plc inputs video wiring interposing relays. We will break it down and go over the wiring to a plc input. Wire 3 black wire is always connected to the load which is the terminal for an input on a plc digital input card.

2 wire 3 wire 4 wire transmitters are available with a wide variety of signal outputs. 4 20 ma transmitter wiring types.