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Wiring 22
Pro
~16 minutes lab time

Wiring 22 — Three-Wire Pt100 RTD

What you'll learn

Terminate a three-wire Pt100 resistance temperature detector on a dedicated PLC temperature input. The single A conductor lands on RTD-A; the two same-colour compensation conductors land on RTD-B1 and RTD-B2.

Lab time: ~16 minutes.

Lesson briefing

Three-Wire Pt100 RTD

Terminate a three-wire Pt100 resistance temperature detector on a dedicated PLC temperature input. The single A conductor lands on RTD-A; the two same-colour compensation conductors land on RTD-B1 and RTD-B2.

Why it is wired this way

A three-wire input cancels lead resistance by assuming the two B leads have equal resistance. Swapping A with either B creates a large measurement error. Ground the cable shield at the panel end only.

Commissioning standard

Before energising, prove protective earth and continuity, verify the drawing terminal-by-terminal, then energise through the protective device and measure the expected supply, signal and return values. Never use this training panel as a substitute for the machine manufacturer’s instructions, risk assessment, isolation procedure or applicable electrical standard.

Hints

Hint 1

Power the temperature input card before wiring the sensing element.

Hint 2

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Hint 3

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Hint 4

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This lesson uses 7 placed components on the lab canvas. Components are vendor-neutral (no proprietary trademarks); the wiring rules apply to any equivalent industrial part.

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