Safety-rated relay outputs for S7-1200
The Siemens 6ES7226-6RA32-0XB0 is a SIMATIC S7-1200 SM 1226 fail-safe digital output module with two relay outputs, each rated 5 A maximum per circuit and 10 A total across all circuits per module. It carries SIL 3 per IEC 61508 and Category 4, PL e per ISO 13849-1 — the highest standard functional-safety rating for a relay output slice, meaning it can be used in safety circuits up to stop category 0 or 1 without a separate safety contactor.
Switching duty and load limits
Relay contacts handle 5 V DC to 30 V DC or 5 V AC to 250 V AC. Resistive load switching is rated 2 Hz max; inductive load switching drops to 0.1 Hz (DC-13) or 2 Hz (AC-15) per IEC 60947-5-1 — the DC-13 figure governs solenoid and brake loads, so plan for one cycle every 10 seconds at rated current. Module draws 120 mA from the 5 V DC backplane bus and up to 300 mA from the 24 V DC load supply L+. Power loss is 10 W typical — that's the heat the enclosure must sink without forced air. Unshielded or shielded cable runs up to 200 m.
Permissible temperature change 5 °C to 55 °C at 3 °C per minute — enough for unheated cabinets in cold climates.
Carries CE, cULus, and FM approvals. Housing is plastic. No short-circuit protection on the outputs — the load circuit needs an external fuse or breaker. Safety metrics: PFDavg below 1.00E-05 in low-demand mode, PFH below 4.00E-09 in high-demand/continuous mode — figures that satisfy SIL 3 loop calculations for both process and machinery safety applications.