GUIDE5 min readUpdated Jun 2026

24 V I/O & isolation on a Raspberry Pi

A Pi's GPIO is 3.3 V and not field-rugged. Isolation is the difference between a hobby wiring job and an industrial one.

SHORT ANSWER

Industrial Pi boards don't expose raw GPIO to the field. They add optically-isolated 24 V digital I/O, analog inputs with surge protection, and a proper ground scheme, so a fault on the field side can't propagate to the compute side. That galvanic isolation is what makes 24 V industrial sensors and actuators safe to wire to a Pi.

24 V DC
the industrial field-signal standard
IEC 61131-2
3.3 V
raw Pi GPIO — never wire it to the field
Raspberry Pi
kV
isolation barriers rated in kilovolts
opto-isolator specs

01Why isolation matters

Field wiring picks up surges, ground loops and inductive kicks from solenoids and motors. An optical or galvanic barrier between the 24 V field side and the 3.3 V logic means those events stop at the barrier instead of destroying your controller.

02Analog and grounding

Analog inputs need surge protection and a clean reference; a shared, star-grounded scheme keeps noise out of your measurements. This is unglamorous engineering, and it's exactly where a hobby build and an industrial one diverge.

Common questions

The ones we're asked on every first call.

No — 24 V will destroy the 3.3 V GPIO. You need an isolated input module (which industrial Pi boards include) to translate and protect the signal.

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