Siemens 3SK1 Time Delay Safety Relay, 24V dc, Single Channel, 4 Safety Contacts

The safety relays of the Advanced series comprise basic devices and input and output expansions. The Advanced devices can be connected by means of a 3ZY12 device connector. When configuring the system, it must be ensured that input expansions are always mounted on the left, and output expansions (3SK121) on the right of the basic unit. For control supply voltages of 110-240 Vac/dc, the Advanced series can be supplied with the necessary 24 Vdc voltage from the 3SK1230 power supply (which must be positioned on the extreme left in the system). The focus of the Advanced relay series is on: single devices that can be flexibly parameterized, expandability using 3ZY12 device connector on both input and output side and basic units with time-delayed enabling circuits / outputs.
On the front of the 3SK1 Advanced basic units, there is a 4-way DIP switch for function setting and 4 LEDs for status and function display. A Set / Reset button can be used to load function settings and to perform a device restart (reset). On commissioning, the devices run a self test in which the internal electronics and firmware are checked for correct functioning. All internal parts of the circuit are cyclically monitored for faults during operation. The semiconductor outputs run through a dark test for up to 2 ms (dynamically) to verify their correct function. The safety relays can be expanded using 3ZY device connectors with input and output expansions.

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)
NO contact/NC contact evaluation via external jumper
Connection interface
Removable terminals

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

2 instantaneous enabling circuits (safety related circuits, NO contacts)
2 time delayed enabling circuits (safety related circuits, NO contacts)
Potentiometer for setting the delay time
Time function: with OFF delay

2 instantaneous solid state outputs
2 time delayed solid state outputs
Potentiometer for setting the delay time
Time function: with OFF delay

The 3SK1 Advanced time delayed basic units have two time delayed and two instantaneous enabling circuits as NO circuits or outputs switching to P potential.

The 3SK1 Advanced safety relays can be used in Emergency Off / Emergency Stop devices in accordance with ISO 60204-1 and in safety circuits in accordance with VDE 0113-1 and / or DIN EN 60204-1, e.g. in circuits in which controlled shutdown, STOP Category 1 is necessary. 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.