Sigmatek - SRO 021 - S-DIAS Safety Relay Output Module, 2x NO, SIL3 / PL e

The Sigmatek SRO 021 is a safety relay output module from the S-DIAS series, engineered for applications requiring high safety standards. It provides two normally open (NO) relay outputs, each capable of handling up to +30 V DC at 6 A. Certified for SIL 3 (EN IEC 62061) and Performance Level e, Category 4 (EN ISO 13849-1/-2), the SRO 021 ensures reliable operation in safety-critical systems. 

Key Features:

• Model: SRO 021

• Brand: Sigmatek

• Article Number: 20-893-021

• Relay Outputs:

  • Number: 2

  • Type: Normally Open (NO)

  • Voltage Range: Up to +30 V DC

  • Maximum Current: 6 A at 55 °C; 4 A at 60 °C

  • Response Time: Typically 10 ms

  • Fall Time: Typically 3 ms

  • Short-Circuit and Overload Protection: External fuse category gG, maximum 6 A

• Safety Certifications:

  • SIL 3 (EN IEC 62061)

  • PL e, Category 4 (EN ISO 13849-1/-2)

  • UL 508 (E247993)

• Mechanical Features:

  • Dimensions (W × H × D): 25 mm × 104.2 mm × 72 mm

  • Mounting: DIN rail

  • Protection Class: IP20

• Environmental Conditions:

  • Operating Temperature: 0 °C to +55 °C (up to +60 °C with derating)

  • Storage Temperature: -20 °C to +85 °C

  • Humidity: 0–95%, non-condensing

  • Altitude: 0–2000 m without derating; above 2000 m, derate maximum temperature by 0.5 °C per 100 m

• Electrical Requirements:

  • Voltage Supply from Safety Bus: +12 V and +24 V

  • Current Consumption: Typically 30 mA (+12 V), 90 mA (+24 V)

• Applications: Ideal for switching higher power loads or potential-isolated circuits, such as hydraulic valves or emergency stop circuits, in safety-critical industrial automation systems.