plc input wiring diagram

Wiring 3 Wire DC NPN and PNP Sensors

by

Wiring 3 wire DC sensors can be confusing. I recently received a question on PNP and NPN sensors. They wanted an explanation of what a sink is and how to wire one. Confusion over the Normally Open and Normally Closed function of the sensor is also a common question. Several diagrams will show a resistor … Read more

Universal Signal Conditioner and Isolator

by

Signal conditioners are used with analog current and voltage signals. They have the ability to change your input analog signal to another output analog signal. As an example, we can have 4-20mA analog input and change it to a 0-10VDC output signal so we can wire this into our PLC. Typically signal conditioners will also … Read more

Wiring an Ultrasonic Proximity Sensor

by

An ultrasonic sensor (switch) is able to detect object presence without physical contact (limit switch). No physical contact means that the switch has no parts that will wear out. The life span of the sensor is increased with less maintenance. An ultrasonic sensor will use sound waves to detect objects. These sound waves are at … Read more

Wiring an NPN PNP Sensor to the Click PLC

by

A proximity sensor (switch) is able to detect object presence without physical contact like a limit switch. No physical contact means that the switch has no parts that will wear out. The life span of the sensor is increased with less maintenance. A capacitive proximity sensor will detect ferrous and non-ferrous objects. The sensor works … Read more

Wiring an Inductive NPN PNP Sensor – Click PLC

by

We will now look at wiring an NPN and PNP inductive proximity sensor to the Click PLC. A proximity sensor (switch) is able to detect object presence without physical contact like a limit switch. No physical contact means that the switch has no parts that will wear out. The life span of the sensor is … Read more

Wiring Push Buttons Switch to Click PLC

by

We will now look at wiring a click plc with selector switch and pushbuttons. A push button (pushbutton) is a simple human interface for controlling some aspect of a machine or process. The push button requires a force to push the button to change the electrical operation from off to on or vice versa. The … Read more

Create an Analog Voltage Input Tester for a PLC

by
Create an Analog Voltage Input Tester for a PLC

We will create a simple and inexpensive analog voltage tester for a PLC using a potentiometer and a 9VDC battery. The potentiometer will be 5K ohms. This should be enough impedance for most analog inputs of the programmable logic controller. (PLC) Voltage impedance for analog voltage inputs is in the megaohm range where the current … Read more

Wiring Interposing Relays – NPN PNP Isolation

by
Wiring Interposing Relays - NPN PNP Isolation

We will now look at wiring interposing relays to connect an NPN and PNP sensors into the PLC. Interposing relay means a device that will separate two different circuits. The isolation can be for current consumption, voltage differences, voltage references, or a combination of both current and voltage. We can use these relays to help … Read more

Here’s a Quick Way to Wire NPN and PNP devices

by

Here’s a Quick Way to Wire NPN and PNP devices I often get asked how to wire NPN and PNP devices to the programmable logic controller. This can be unclear at first when looking at the wiring diagrams. I have managed to destroy a few sensors in the process….. so let’s get started, and I … Read more