Built for the pit: temperature range and relay muscle
This Siemens 6AG1223-1PL32-2XB0 digital I/O module packs 16 inputs and 16 relay outputs into a compact 70 x 100 x 75 mm footprint. The relay outputs handle both AC and DC loads: rated 5 V AC to 250 V AC and 5 V DC to 30 V DC, with a lamp load capability of 30 W on DC and 200 W on AC. That covers pilot lights, contactor coils, and small solenoid valves without needing an interposing relay.
Current production — no obsolescence watch needed
Typical power loss is 10 W. Factor that into your enclosure thermal budget — in a densely packed cabinet that heat adds up, especially if the module sits next to a power supply or a processor.
Input characteristics and wiring realities
Digital inputs are DC type, with signal '1' at 15 V DC at 2.5 mA min, 4 mA typical. Signal '0' threshold is 5 V DC at 1 mA. Input delay is 10 ms max in both directions — fast enough for most discrete sensing, but not for high-speed counting. Shielded cable runs up to 500 m; unshielded drops to 150 m. Short-circuit protection is not built in — the spec explicitly states it must be provided externally. Plan for a fuse or electronic circuit breaker per output group. The module requires a front connector (ordered separately).