16 inputs, 16 relay outputs — the I/O count that fits the BOM
The 6ES7223-1PL30-0XB0: This SM 1223 packs 16 digital inputs and 16 relay outputs into a single S7-1200 expansion module. The input thresholds are standard 24 V DC: signal 0 at ≤5 V DC at 1 mA, signal 1 at ≥15 V DC at 2.5 mA — no level-shifting needed for most 24 V sensors. Relay outputs handle 5–250 V AC and 5–30 V DC, with a lamp-load limit of 30 W DC or 200 W AC. That covers solenoid valves, contactor coils, and indicator lamps without external interposing relays — but watch the inrush on incandescent loads.
Operating temperature spans -40 to 70 °C, so cold-storage lines or hot cabinet corners are within range. IP20 means open-panel only — no washdown, no dust seal.
Cable runs and diagnostics — 500 m shielded, 150 m unshielded
Inputs accept cable runs up to 500 m shielded or 150 m unshielded. For remote sensor clusters near the machine perimeter, that's enough to keep the I/O rack central and still reach the far end of the line. Diagnostic alarm and status-of-inputs functions are built in — no separate signal-conditioning card needed for fault detection on the field wiring.
Approvals and compliance — CE, FM, RCM
That covers EU machinery directive, US FM for industrial control equipment, and Australian/New Zealand EMC. No UL or CSA listed in the spec — verify if your panel requires those specifically.