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Instrumentation

Measuring the process: RTDs and thermocouples, pressure and level transmitters, loop-powered devices, calibration, and the PID loop that acts on what they read.

Instrumentation is where the control system meets physics. An RTD and a thermocouple both give you temperature and behave nothing alike; a level reading can be depth, mass or volume depending on what you assumed about density. These guides cover what each device really measures and how to get it into the controller honestly.

4 articles in this hub

Flat vector diagram comparing RTD and thermocouple wiring to PLC input modules mounted on a DIN rail
rtd vs thermocoupletemperature sensorsplc instrumentation

RTD vs Thermocouple: Which Should You Wire to Your PLC?

RTD vs thermocouple: a direct comparison of accuracy, temperature range, response time, wiring types and which PLC input module to use for each sensor.

Aug 9, 2026 · 9 min read

4-20 mA scaling in a PLC diagram showing raw count to engineering unit conversion
4-20maanalog scalingstructured text

4-20 mA Scaling in a PLC: ST and Ladder Code

Turn a raw 0-32767 analog count into bar, °C or m³/h. Full 4-20 mA scaling walkthrough with structured text and ladder code for Studio 5000 and TIA Portal.

Jul 12, 2026 · 7 min read

4-20 mA scaling formula diagram showing PLC analog input conversion to engineering units
4-20maanalogscaling

4-20 mA Scaling Formula: The PLC Engineer's Guide

Master the 4-20 mA scaling formula for PLCs. Covers the math, raw count ranges, live worked examples, and structured text code you can use today.

Jun 30, 2026 · 6 min read

PLC analog input wiring diagram showing 4-20 mA transmitter connected to Siemens S7 analog input module
analog input4-20mainstrumentation

PLC Analog Input Wiring: 4-20 mA Step by Step

Wire a 4-20 mA transmitter to a PLC analog input without ground loops or signal noise. Covers 2-wire, 3-wire, 4-wire devices, shielding and raw count scaling.

Jun 29, 2026 · 6 min read