Siemens Safety Relay

The 3SK1 output expansion units are used to expand the enabling circuits. The maximum Performance Level PL / Cat. in accordance with ISO 13849-1, SILCL in accordance with IEC 62061, SIL in accordance with IEC 61508 corresponds to the Performance Level PL and SIL of the basic unit when the connection between basic unit and output expansion is configured as fail safe (e.g. basic unit and output expansion are connected using 3ZY12 device connector ). The output expansions can be activated via the supply voltage (A1/A2) or using 3ZY device connectors.
The operating state of the 3SK1 output expansions is displayed on the LED. The output expansions 3SK1211(4RO) have four safety related enabling circuits as NO circuits, and the output expansions 3SK1213 (3RO) have three. They each have one positively driven NC circuit. The output expansions can be activated via any enabling circuit / output of the basic unit via (A1). The NC circuit 51/52 of 3SK1211 (4RO) or 41/42 of 3SK1213 (3RO) is used for monitoring the output expansions. In the 24 V DC variants, the expansion units can be activated and evaluated via the 3ZY device connectors.

Slide switch for selecting the activation type (time delayed / instantaneous - for 24 Vdc variant only)
1 LED for status display
4 enabling circuits (safe circuits, NO contacts)
1 NC circuit as feedback contact for output expansion 3SK1211 to the up-circuit basic unit
Enclosure width 22.5 mm
Removable terminals

Slide switch for selecting the activation type (time delayed / instantaneous - for 24 Vdc variant only)
1 LED for status display
3 enabling circuits (safe circuits, NO contacts)
1 NC circuit as feedback contact for output expansion 3SK1213 for the up-circuit basic unit
Enclosure width 90 mm
Removable terminals

When using the 3ZY connector you can switch between instantaneous or delayed control of the basic unit using the slide switch of the output expansion, but when using conventional wiring the slide switch has no function.