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Mitsubishi Electric RD78G32 — PLC I/O & Expansion Modules

Mitsubishi RD78G32 MELSEC iQ-R PLC Expansion Module

MPNRD78G32

Mitsubishi MELSEC iQ-R series PLC expansion module, module RD78G32, classified as PLC Expansion Modules, listed mass 2.27 kg.

Sourced new & surplus through independent channelsAuthenticity-screened · ESD-safe packingListing updated Jul 2026

Specifications

RD78G32 — Specifications
ParameterValue
Weight2.27 kgs

Product details

What RD78G32 is on the BOM

The Mitsubishi RD78G32 sits in the MELSEC iQ-R family as a PLC expansion module on the iQ-R backplane — a class of slice modules the series dedicates to motion and high-speed I/O rather than the base CPU slot. It files under PLCs and Accessories, sub-class PLC Expansion Modules, top-class PLCs & HMIs, which mirrors how the iQ-R racks treat any non-CPU base unit: a backplane-resident drop that inherits the CPU's project and power budget.

Lifecycle reading

Where the class is used

PLC Expansion Modules on the MELSEC iQ-R platform cover the high-speed, motion and dedicated-network slices that don't belong in the CPU's local I/O table — the kind of slots filled when a line needs multi-axis motion, a high-speed counter, or a specific fieldbus beyond the CPU's built-in ports.

Frequently asked questions

When sourcing RD78G32, what's the closest functional second-source — QD70P8?

QD70P8 is a MELSEC-Q positioning module, so it isn't a drop-in for the iQ-R RD78G32 — they're separate rack families. Same-class second-sourcing inside iQ-R would be a different RD-series motion slice, not the Q-series QD70P8.

What is RD78G32's listed weight (2.27 kg) on this component line?

The line lists 2.27 kg on the data sheet — heavier than a digital I/O block, in line with iQ-R slices that carry on-board processing.

Will RD78G32 drop into a panel that was specified around QD70P8 without rewiring?

No. RD78G32 lives on the MELSEC iQ-R backplane; QD70P8 lives on MELSEC-Q. They aren't slot-swap compatible — at minimum the base rack, CPU and project have to move with the migration.

MPN
RD78G32