Siemens 3TK28 Safety Relay, 24V dc, Single Channel, 1 Safety Contacts

Evaluation units with sold-state components such as the SIRIUS 3TK28 4 Safety Relay are becoming increasingly established in safety applications, as a considerably higher number of starting operations and electrical life of the devices is achieved with permanent functional checks and consistently wear-free work. The compact and light design of these safety relays also permit series connection or normal operating switching, e.g. through a PLC.
If multiple or potential-free enabling circuits are required in an application, the devices can be expanded using the 3TK28 30 expansion units.

Permanent function checking
No wear because switched electronically
High switching frequency
Long electrical endurance
Evaluation of solid-state sensors
Sensor lead up to 2000m max.
Cascading possible
Insensitive to vibrations and dirt
Compact design, low weight
Approved for the world market
Suitable for use with Expansion module 3TK28 30
Two solid state outputs for interface with PLC's
Cross channel monitoring available on all units except stock no. 455-5251
Width 22.5 mm

Usual combinations of safety applications, such as EMERGENCY-STOP and protective door monitoring, could only be realized in the past by using several individual safety relays. The SIRIUS 3TK28 45 Safety Relay unifies several functions in a single device. Two solid-state and two relay enabling circuits ensure a quick, safe disconnection in just a few actions.