Topic hub

Wiring and Sensors

Getting signals into and out of the controller: sinking and sourcing, NPN and PNP, 3-wire and 4-wire sensors, 4-20 mA and 0-10 V analog wiring, and how to scale a raw count into engineering units.

Sinking versus sourcing is the single most common wiring mistake in this field, and it is not a difficult idea once you stop thinking about the sensor and start thinking about which way current leaves the input terminal. These guides cover discrete and analog field wiring end to end, including the scaling maths that turns counts into pressure, level or temperature.

8 articles in this hub

Flat vector wiring diagram of a 4-wire PNP proximity sensor connected to a PLC digital input module showing brown, blue, black and white wire connections
proximity sensorsplc wiringsensor wiring

4-Wire Proximity Sensor Wiring to a PLC

A 4-wire proximity sensor gives you both a NO and NC output from one body. Learn exactly how to wire each output type to your PLC input module, with real gotchas.

Aug 6, 2026 路 9 min read

Flat vector infographic of three photoelectric sensor modes connected to a PLC rack, showing through-beam, retro-reflective and diffuse beam paths on a conveyor
photoelectric sensorplc wiringsensor types

Photoelectric Sensors: Types, Wiring and PLC Use

Learn how photoelectric sensors work, how to wire them to a PLC input, and when to choose through-beam vs diffuse vs retro-reflective mode. Real field gotchas included.

Aug 5, 2026 路 10 min read

Flat vector diagram showing PNP and NPN proximity sensor wiring connections to a PLC input module with labeled wire colors and current flow arrows
proximity sensor wiringplc sensorspnp npn wiring

Proximity Sensor Wiring to a PLC: Full Guide

Learn how to wire 2-wire, 3-wire and 4-wire proximity sensors to a PLC input. Covers PNP and NPN types, color codes, sinking vs sourcing inputs, and common wiring mistakes.

Aug 5, 2026 路 9 min read

Flat vector diagram comparing an inductive proximity sensor detecting a metal gear and a capacitive proximity sensor detecting a plastic container, both wired to a PLC input module
proximity sensorsplc wiringsensor selection

Inductive vs Capacitive Proximity Sensors: Full Guide

Inductive and capacitive proximity sensors look identical but detect completely different targets. Learn the key differences, typical specs, and wiring rules for PLC integration.

Aug 5, 2026 路 9 min read

Flat vector wiring diagram comparing NPN and PNP sensor connections to a PLC digital input module showing current flow direction for each type
npn vs pnp sensorssensor wiringplc inputs

NPN vs PNP Sensors: Wiring and PLC Connection

NPN and PNP sensors switch current in opposite directions. Get the wrong one for your PLC input card and the signal never works. Here is how to tell them apart and wire each type correctly.

Aug 5, 2026 路 8 min read

Flat vector diagram of DIN rail terminal blocks showing conductor entry points, jumper bar, label tags and grounding terminal on a 35mm rail
din rail terminal blockscontrol panel wiringplc wiring

DIN Rail Terminal Blocks: Wiring and Selection Guide

DIN rail terminal blocks are the backbone of every control panel. This guide covers types, sizing, torque specs, jumper use, and common wiring mistakes that cause real field problems.

Aug 4, 2026 路 11 min read

Flat vector diagram of a PLC control panel showing VFD-generated electrical noise radiating toward analog signal cables and I/O modules
plc wiringelectrical noiseinterference

PLC Panel Electrical Noise: Causes and Fixes

Electrical noise in PLC panels causes phantom inputs, drifting analog readings and comm errors. Learn the real causes and practical fixes, wiring changes included.

Aug 4, 2026 路 10 min read

Flat vector diagram of a PLC analog output module wired to a control valve positioner on a 4-20 mA loop and a VFD on a 0-10 V voltage output channel
analog output wiring4-20ma outputplc wiring

PLC Analog Output Wiring: 4-20 mA and 0-10 V

Step-by-step guide to wiring PLC analog outputs: 4-20 mA current loops and 0-10 V voltage signals, with real wiring gotchas, load limits and field-verified tips.

Aug 3, 2026 路 11 min read