EUCHNER CETx-AR-xxx-AH-xxx (Unicode) - Manual (Page 6)

Operating Instructions Safety Switch CET.-AR-...-AH-...
6
Function
Function of the electronics
Safety switches series CET-AR permit locking of movable safety guards. They meet
the following safety requirements:
Ì Category 3, PLe according to EN ISO 13849-1 (head mounted upward)
Ì Category 4, PLe according to EN ISO 13849-1 (head mounted downward or
horizontal)
Ì Redundant design of the circuit in the unit with self-monitoring
Ì The safety system still functions even if an internal component fails
Ì The switch state of the semiconductor outputs is continuously monitored inter-
nally
Ì Short circuit detection at the safety outputs by pulse signals
The following switch-on condition applies to safety outputs OA and OB (see also
System status table and the section Typical system times):
Ì Safety guard closed
Ì Guard locking active (actuator completely inserted into recess)
Ì Both safety outputs (IA and IB) must be switched on
Ì Feedback loop closed (only for version with feedback loop/start button)
The system consists of the following components: coded actuator (transponder)
and switch.
Each actuator has a unique electronic coding and is therefore a unique element.
The code in an actuator cannot be reprogrammed.
The actuator must be assigned to the safety switch by a teach-in process so that
it is detected by the system. This unambiguous assignment ensures a particularly
high level of protection against tampering.
The safety switch with integrated evaluation unit and read head is fastened to the
fixed part of the safety guard.
The actuator attached to the movable part of the safety guard is moved towards
the read head fitted in the safety switch by closing the door. When the switch-on
distance is reached, power is supplied to the actuator by the inductive read head
and data can be transferred.
The bit pattern read is compared with the code saved in the safety switch. If the
data match, the safety outputs are enabled.
Due to the combination of dynamic polling of the actuator and the redundant,
diverse design of the safety electronics with the two feedback safety outputs, the
safety switch will enter the safe state with every detectable fault.
When the safety guard is opened, the safety outputs switch off the safety circuit
and the monitoring output OUT is switched off. The state of the safety outputs is
monitored internally by two microprocessors.
In the event of a fault in the safety switch, the safety circuit is switched off and
the DIA LED illuminates red.
The safety switch has a redundant circuit design with self-monitoring. This means
that the safety system is still effective even if a component fails.
Lift tappet
Slide
Transponder
Spring-
mounted
guard
locking pin
Recess