Siemens Single/Dual-Channel Light Beam/Curtain Safety Relay, 24 → 240V ac/dc, 4 Safety Contacts

3TK28 26, Configurable Safety Relay, 8 Selectable Functions

Simultaneously monitors all of the sensor and actuator functions and ensures that outputs are shut down in a safety-relevant fashion. The safety relay has two terminals for the sensors: The cascading input CAS/OS as sensor input S1. The following components can be connected at the sensor input: sensors with contacts, e.g. EMERGENCY STOP or position switches, electronic sensors, e.g. light grids and light barriers, contact mats, magnetically operated switches, NC/NC or NC/NO. The cascading input can be ANDed with other safety relays or to control the device from a machine control system. Suitable for the following applications: up to category 4 according to EN 954-1, up to SIL 3 according to IEC 61508

Up to eight parameters can be configured therefore reducing the variety of devices in the control cabinet
Selectable parameters include: Cross-fault detection, evaluation, connection type, debouncing time, start type sensor input, start type cascading input,start-up test and start-up after power failure.
Integrated status display for sensor and actuator states
Connection with all conventional sensor types
For Cat. 2 according to EN 954-1, only one contactor is required in the shutdown circuit as the shutdown fault in the actuator circuit is automatically signalled
Compact design, creates more space in the control cabinet
Flexible connectivity
Removeable terminals