Siemens 3TK28 - Display of the Operating State

Description of the individual safety relays
3.6 3TK28 safety relays with relay enabling circuits
3TK28 safety relays
Manual, 07/2016, NEB926157502000/RS-AB/003
49
3.6.3.6
Display of the operating state
The operating state and functioning of the device are indicated by three LEDs:
● POWER
● CHANNEL 1
● CHANNEL 2
Operating states of 3TK2822/23
= off
= on
LED
Operation
POWER CHANNEL 1 CHANNEL 2 Line supply EMERGENCY
STOP
ON Enabling circuit
On Not pressed Pressed Closed
Pressed
Not pressed
Open
Not pressed
Not pressed
Open
Fault
• Relay welded
• Motor contactor welded
• Fault in electronics
• Short-circuit in ON circuit (on 3TK2823 only)
Open
Cross-circuit in EMERGENCY STOP circuit
(minimum fault current I
Kmin
= 0.5 A; PTC fuse
responds) or no supply voltage