Siemens SIRIUS 3TK2826 Manual page 32

Configuration / project engineering
9.3 Explanation of the device's functions
2. Additional safety sensor circuit
The cascading input is AND connected with the sensor inputs Y12, Y22.
Safety category 2 in accordance with EN 954-1 can be achieved if the cascading input is
wired with single-channel (positive opening) safety sensors (supply via T3) and if the
connecting cable is laid in a protected fashion. The start function for the cascading input
can be defined independently of the sensor inputs Y12, Y22 (autostart or monitored
start).
The cascading input 1 can be triggered with floating or solid-state contact blocks
(switching to P potential). Floating contact blocks must be connected between T3 and the
cascading input.
3. Normal switching duty
The cascading input can also be used for normal switching duty (not safe). The cascading
input can be triggered with floating or solid-state contact blocks (switching to P potential).
Current source
In the case of solid-state contact blocks (possible only in the case of 3TK2826-*BB4*),
make sure that the contact blocks are powered from the same current source as the device.
32
WARNING
Current source
In the case of solid-state contact blocks (possible only in the case of 3TK2826-*BB4*),
make sure that the contact blocks are powered from the same current source as the
device.
Floating contacts must be connected between T3 and 1.
In this application, the start function for cascading input 1 must be set to "Autostart".
WARNING
3TK2826 safety relay
Manual, 08/2007, GWA NEB 926 1579-02 DS 02