Siemens SIRIUS 3SK1 Safety Monitoring Safety Relay, 24V dc, Single Channel

The safety relays of the Standard series can be configured as stand alone devices or as an expandable solution with conventional wiring technology. The focus of the Standard series is on: single devices for simple safety applications, output side expansion by means of expansion units and external wiring. No expansion is possible on the input side.

Emergency Off / Emergency Stop monitoring
Monitoring of protective doors with electromechanical position switches, solid state position switches, or solenoid switches
Monitoring of contact free protection equipment, e.g. light arrays / light barriers, or laser scanners

The SIRIUS 3SK1111 is a two-channel safety relay for EMERGENCY OFF and EMERGENCY STOP equipment in accordance with EN 60204-1. The unit is equipped with a positively driven relay and monitors itself during every ON/OFF cycle. The safety relay has three enabling circuits (safety related circuits) as NO circuits and a signalling circuit (non-safety related circuit, NC contact). On the front of the 3SK1111 basic unit there is a slide switch for function setting and two LEDs for displaying the operating states.

2 sensor inputs (channels 1 and 2)
1 input for feedback circuit and START button
3 enabling circuits (safety related circuits, NO contacts)
1 signalling circuit (non-safety related circuit, NC contact)
2 LEDs for displaying the operating states
Slide switch for function setting
Single channel or two channel connection
Cross circuit detection between sensor channels 1 and 2
Enclosure width 22.5 mm
Removable terminals

The SIRIUS 3SK1112 safety relay has two safety related solid state safe outputs and one non-safety related signalling circuit. On the front of the safety relay there is a 4-way DIP switch for function setting and 4 LEDs for status and function display. The SET / RESET button is used to load function settings and to restart the unit (reset). On commissioning, the 3SK1112 standard basic unit runs through a self test. This checks that the internal electronics and firmware are functioning correctly. All internal safety critical parts of the circuit are cyclically monitored for faults during operation.

4-way DIP switch for function setting (parameterization)
SET / RESET button
4 LEDs for status and function display
2 sensor inputs (channels 1 and 2)
1 input (cascading circuit)
1 input (START pushbutton circuit)
1 input (feedback circuit)
2 test outputs
2 safe solid state outputs
1 solid state signalling circuit
Enclosure width 22.5 mm
Removable terminals

The 3SK1 safety relay can be used in Emergency Off / Emergency Stop devices in accordance with ISO 13850 and in safety circuits in accordance with VDE 0113-1 and/or DIN EN 60204-1. Depending on the external circuit, it is possible to achieve SILCL 3 in accordance with IEC 62061, SIL 3 in accordance with IEC 61508 and PL e (Cat. 4) in accordance with ISO 13849-1.

This safety relay enhances safety monitoring in automation systems with a supply voltage of 24 V DC. Operating with a single channel, it is pivotal for industrial applications that require risk management and compliance with safety standards. Its performance levels and safety integrity ratings make it suitable for professionals in automation and electrical fields.

• Automatic reset methods facilitate continuous operation
• Monitored start capability strengthens system safety
• Cross-circuit detection enhances fault tolerance
• Compact design enables versatile installation
• High safety category of ISO 13849-1 ensures compliance
• SIL 3 rating meets stringent safety requirements

• Monitoring safety-related circuits in machinery
• Implementing emergency stop functions in systems
• Sensor monitoring in industrial automation
• Utilisation with light barriers and protective door systems
• Suitable for laser scanners in safety-critical environments

The automatic start function ensures that systems engage safely after a reset, minimising the risks associated with unintended operation.

It accepts both floating and non-floating sensors for flexible monitoring in safety applications.

Yes, it is designed for easy integration, fitting various control systems without extensive modifications.

This device operates effectively within a temperature range of -25° to +60°C, making it suitable for diverse environments.

Screw terminal connections accommodate various wire sizes, allowing flexibility in electrical setups while ensuring secure connections.