EUCHNER CES-I-AP-U-C04 (Unicode) - Manual (Page 6)

Operating Instructions Safety Switch CES-I-AP-U-C04
6
Function
The device complies with the following safety requirements:
Ì Safety category 4, PLe according to EN ISO 13849-1
Ì Redundant design of the circuit in the unit with self-monitoring
Ì This means that 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 pulsed signals
The following switch-on condition applies for the safety outputs FO1A and FO1B
(see also System status table and section Typical system times):
Ì Safety guard closed
The CES system consists of the following components: coded actuator (transpon-
der) and switch.
Every EUCHNER actuator supplied has an electronic coding (unique coding) that is
read by the read head. Only if a correct coding is detected does the system accept
the actuator. The code in an actuator cannot be reprogrammed.
The actuator must be assigned to the safety switch by a teach-in operation so that
it is detected by the system. This unambiguous assignment ensures a particularly
high level of protection against tampering.
The safety switch 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 read head by induc-
tion 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. Independent of the safety outputs, monitor-
ing output OD switches on as soon as the actuator is in the operating distance.
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 OD is switched off. The state of the safety outputs is
monitored internally by two microprocessors.
If faults are detected, the safety circuit is switched off and the DIA LED illuminates.
In case of devices with a monitoring output OI, the output is switched on.
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.
The system is designed so that failures will not result in the loss of the safety func-
tion. The occurrence of failures is detected by cyclic self-monitoring at the latest
on the next demand to switch the safety outputs (e.g. on starting).