SIRIUS 3SK Safety Relays

3SK1 safety relays

SIRIUS 3SK1 safety relays are used mainly in autonomous safety applications which are not connected to a safety-oriented bus system. Their function here is to evaluate the sensors and the safety-oriented shutdown of hazards. Also they check and monitor the sensors, actuators and safety-oriented functions of the safety relay.

3SK2 safety relays

SIRIUS 3SK2 safety relays are used mainly in autonomous and more complex safety applications, in which the functional scope of the 3SK1 devices is no longer adequate, e.g. when implementing independent trip functions. Their function here is to evaluate the sensors and the safety-related shutdown of hazards. They also check and monitor the sensors, actuators and safety-oriented functions of the safety relay.

SIRIUS 3SK safety relays are the key elements of a consistent, cost-effective safety chain. Whether you need EMERGENCY-STOP functionality, protective door monitoring, light arrays, laser scanners or the protection of presses or punches – slimline SIRIUS safety relays enable all safety applications to be implemented in the best possible way in terms of engineering and price.

The following safety-related functions are available:

• Monitoring the safety functions of sensors
• Monitoring the sensor leads
• Monitoring the correct device function of the safety relay
• Monitoring the actuators in the shutdown circuit
• Safety-related disconnection when dangers arise

SIRIUS 3SK safety relays are approved for applications up to SIL 3 (IEC 61508/IEC 62061) or PL e (EN ISO 13849-1).

Device series

SIRIUS 3SK safety relays stand out on account of their flexibility in both parameterization and system configurations with several evaluation units. Optimized solutions when selecting components are facilitated by a clearly structured component range:

• 3SK1 Standard basic units
• 3SK1 Advanced basic units
• 3SK2 basic units
• 3SK output expansions
• 3SK1 input expansions
• Accessories

3SK1 Standard basic units

The 3SK1 Standard basic units are characterized by the following features:

• Compact design
• Simple operation
• Relay and semiconductor outputs
• Economical solution

3SK1 Advanced basic units

The 3SK1 Advanced basic units additionally offer:

• Universal application opportunities thanks to multifunctionality
• Time-delayed outputs
• Expansion of inputs and outputs

3SK2 basic units

In addition, 3SK2 basic units offer:

• Up to six fail-safe trip functions
• Flexible application thanks to software parameterization
• Powerful semiconductor outputs
• Convenient diagnostics using diagnostics display and configuration software

In the case of 3SK1 Advanced basic units or 3SK2 basic units, the 3ZY12 device connector allows safety functions involving several sensors and actuators to be set up very quickly.

System configuration example with 3SK1121

The 3SK1 Standard and Advanced and 3SK2 ranges are high-quality replacements for 3TK28 safety relays. In their narrow design, and equipped with greater functionality, they can replace any 3TK28 device. The only exceptions to this are 3TK2810 devices.

Note:

For converting from 3TK28 to 3SK, seehttp://www.siemens.com/sirius/conversion-tool.

Overview of functions of the 3SK series

✓ Available

-- Not available

¹⁾ 24 V basic units only.

²⁾ 24 V AC/DC.

³⁾ Possible using 3SK1230 power supply via device connector.

⁴⁾ Up to 4 independent safe outputs, two of which via device connector.

⁵⁾ Up to 6 independent safe outputs, two of which via device connector.

Parameter assignment

3SK112 and 3SK1112 with DIP switches

The 3SK112 and 3SK1112 safety relays are configurable safety relays. They are used as evaluation units for typical safety chains (detect, evaluate, respond). A number of functions can be set using the DIP switches on the front. Thus the 3SK112 and 3SK1112 can be used universally.

DIP switch No.	OFF	ON	Circuit diagram
1	Autostart sensor input	Monitored start sensor input
2	Without cross-circuit monitoring	With cross-circuit monitoring
3	2 x single-channel sensor connection	1 x 2-channel sensor connection
4	With start test	Without start test

3SK2 with software

3SK2 safety relays are configured using the SIRIUS Safety ES software. This means that the response of a 3SK2 unit, as well as the function of the individual safe outputs, can be parameterized easily and conveniently in the logic diagram. In addition, the configuration can be printed out for documentation purposes. The software also supports the user during commissioning and troubleshooting by means of online diagnostics and the option of being able to “force" signals in the logic plan. Through this, 3SK2 safety relays are able to offer maximum flexibility and universal application options.

Note:

For more information on SIRIUS Safety ES, see “Parameterization, Configuration and Visualization for SIRIUS".

Innovative enclosure concept for SIRIUS 3SK safety relays

Can be expanded by adding the 3RM1 motor starter

With previous safety relay and motor feeder configurations, a huge amount of wiring was required to monitor motor feeders in safety applications.

Conventional system configuration

Through the integration of SIRIUS 3RM1 motor starters into the SIRIUS 3SK safety relay system family, this wiring has been minimized for the first time.

Motor starters up to 3 kW can be easily integrated into the safety relay system using SIRIUS 3ZY12 device connectors, without the need for additional wiring between the evaluation unit and the motor starter.

3SK1 and 3RM1 system design

Article No. scheme

3SK1

3SK2

Note:

The article No. scheme is presented here merely for information purposes and for better understanding of the logic behind the article numbers.

General

• Approved for all safety applications because of its compliance with the highest safety requirements (SIL 3 and PL e)
• Universally usable thanks to adjustable parameters
• Usable worldwide thanks to globally valid certificates
• Compact SIRIUS design
• Device connectors with standard rail mounting for flexible connectability and expandability
• Removable terminals for greater plant availability
• Yellow terminal covers clearly identify the device as a safety component.
• Sensor cable length up to 2 000 m allows it to be used in plants covering large areas

Relay outputs

• Different voltages can be switched through the floating contacts
• Currents up to 5 A can be switched with relay contacts (AC-15/DC-13)

Semiconductor outputs

• Wear-free
• Suitable for operation in fast switching applications
• Insensitive to vibrations and dirt
• Good electrical endurance

Power outputs (3SK1213 output expansion)

• Different voltages can be switched through the floating contacts
• The power relay contacts allow currents of up to 10 A AC-15/DC-13 to be connected.
• Long mechanical and electrical endurance
• Protective separation among the safe outputs and between safe outputs and electronics

Can be expanded by adding the 3RM1 motor starter

SIRIUS 3SK safety relays are ideal for combining with SIRIUS 3RM1 motor starters.

Combinations are made by means of

• SIRIUS 3ZY1 device connectors (in combination with 3SK1 Advanced/3SK2) or
• conventional wiring (for all 3SK1 und 3SK2 basic devices).

This makes collective shutdown very easy in assemblies. The wiring, and ultimately the shutting down of the control supply voltage for the expansion components in EMERGENCY-STOP situations, is performed via the device connector. There is no further need for complex looping of the connecting cables between the safety relay and the motor starters.

The 3RM1 motor starter combines the benefits of semiconductor technology and relay technology. This combination is also known as hybrid technology.

The hybrid technology in the motor starter is characterized by the following features:

• The inrush current in the case of motorized loads is routed briefly via the semiconductors. Advantages include protection of the relay contacts and a long service life due to low wear.
• The uninterrupted current is conducted via relay contacts. Advantages include lower heat losses compared with the semiconductor.
• Shutdown is implemented again via the semiconductor. The contacts are only slightly exposed to arcs, and this results in a longer service life.
• Integrated overload protection

Note:

For SIRIUS 3RM1 motor starters, see "Load Feeders and Motor Starters for Use in Switchgear Cabinets" → "SIRIUS 3RM1 Motor Starters".

3ZY12 device connectors

Using 3ZY12 device connectors to combine devices reduces the time required to configure and wire the components. At the same time errors are avoided during wiring, and this considerably reduces the testing required for the fully-assembled application.

Configuration and stock keeping

Variable setting options by means of DIP switches or software, a wide voltage range (3SK1111) and a special power supply unit (3SK1 only) reduce the cost of spare parts storage and simplify the considerations during configuration with regard to the evaluation units to be selected.

Spring-type terminal with push-in functionality

Push-in connections are a form of spring-type terminals allowing fast wiring without tools for rigid conductors or conductors equipped with end sleeves.

As with other spring-type terminals, a screwdriver (with 3.0 x 0.5 mm blade) is required to disconnect the conductor. The same tool can also be used to wire fine-stranded or stranded conductors with no end finishing.

The advantages of the push-in terminals are found, as with all spring-type terminals, in speed of assembly and disassembly and vibration-proof connection. There is no need for the checking and tightening required with screw-type connections.

For the manual "3SK1 Safety Relays" see

https://support.industry.siemens.com/cs/ww/en/view/67585885.

For “3SK2 safety relays” manual, see

https://support.industry.siemens.com/cs/ww/en/ps/16386.