The NJ-AX4-33 from Fuji Electric is an analog input module that lives in the PLC expansion slot — it's the slice that brings real-world 4-20 mA or voltage signals into the logic. Listed under PLCs and Accessories, subcategory PLC Expansion Modules, it's built for adding analog channels to a Fuji PLC rack without swapping the whole controller.
What it does in the rack
As an analog input module, the NJ-AX4-33 takes field signals — pressure transmitters, temperature probes, flow meters — and converts them into digital values the PLC CPU can act on. Four input channels is the usual count for this form factor, though the exact input type (voltage or current) and resolution depend on the module's configuration. The module sits on the expansion bus, addressed by the rack slot position; no rotary switches or DIPs to set.