EUCHNER CES-AH-C03-AH-SM (Unicode) - Manual (Page 6)

Operating Instructions Safety Switch CES-AH-C03-AH-SM
6
System description
The safety switch CES-AH-C03-AH-SM complies with the following safety require-
ments:
Ì Category 3 according to DIN EN ISO 13849-1
Ì Proximity device with self-monitoring type PDF-S according to EN 60947-5-3.
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
The CES non-contact safety switch consists of three components: coded actuator,
evaluation unit and read head.
The evaluation unit is integrated into a housing with the read head.
Each actuator possesses a unique electronic coding and so is a unique element in
the system used. 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.
Within the device, the operation of the two safety outputs is dual-channel.
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 switching elements for each
safety output, the safety switch will enter the safe state with every detectable fault.
The safety outputs shut down the safety circuits if the safety guard is opened.
The state of the safety outputs is monitored internally by two microprocessors.
For the safety outputs to switch on, there must be a voltage of U
B
on the START
input. This voltage can be supplied either using a jumper (automatic start) or using
a start button.
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 a failure will not result in the loss of the safety
function. The occurrence of failures is detected by cyclic self-monitoring at the
latest on the next demand to close the safety contacts (e.g. on starting).