An Easy Way to Remember PNP and NPN Sensor Wiring

This post was published first at Automation-Insights Blog of Balluff Inc.

Here’s a simple way remember how to wire up a 3-wire DC PNP or NPN sensor:
PNP = Switched Positive
NPN = Switched Negative
“Switched” refers to which side of the controlled load (relay, small indicator, PLC input) is being switched electrically. Either the load is connected to Negative and the Positive is switched (PNP), or the load is connected to Positive and the Negative is switched (NPN). These diagrams illustrate the differences between the two connections.
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2.14.2018_PNP v NPN Graphic

Some more details on what you need to know about wiring of sensors on our website

If you want to learn more basic knowledge on sensor and automation topics visit this post with interesting links & information

Basics of Automation
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[…] of tools in machine tool spindles several options are possible: Sensors with binary output (e.g. PNP normally open) or sensors with continous output (e.g. 0..10V or IO-Link) may be installed. The clamping process […]

Gemma Dasí Ruiz
December 28, 2020 12:41 pm

Really good electric scheme. It shows the idea clearly

[…] Typical outputs are PNP or NPN normally open switching. […]

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