EUCHNER CES-A-UEA-04B (Multicode) - Manual (Page 6)

Operating Instructions Safety System CES-A-UEA-02B/CES-A-UEA-04B
6
Function
The safety system CES-A-UEA... complies with the following safety requirements:
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Category 4, PLe according to EN ISO 13849-1
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Proximity device with self-monitoring type PDF-M according to EN 60947-5-3.
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Redundant design of the circuit in the evaluation unit with self-monitoring. As a
result, the safety system is still effective even if a component fails.
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When the safety guard is opened and closed, it is checked whether the safety
system relays open and close correctly.
The CES non-contact safety system consists of three components:
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Coded actuator
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Read head
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Evaluation unit
1 to 2 read heads can be connected to the CES-A-UEA-02B evaluation unit and 1
to 4 read heads can be connected to the CES-A-UEA-04B evaluation unit.
It is also possible to connect a start button (monitoring of the falling edge) and a
feedback loop for monitoring external relays and contactors.
The individual configuration is defined by a setup procedure.
Each delivered actuator possesses a unique electronic coding and so is a unique
element in the system used. The code in an actuator cannot be reprogrammed.
Unlike systems with unique code detection, on the CES-A-UEA... a specific code is
not polled but instead it is only checked whether the actuator is of a type that can be
detected by the system (multicode detection). There is no exact comparison of the
actuator code with the code defined in the evaluation unit (unique code detection).
The read heads are fastened to the fixed part of the safety guard and are each
connected to the evaluation unit via a two-core screened cable.
The actuator fastened to the movable part of the safety guard is moved towards the
read head by closing the door. When the switch-on distance is reached, power is
supplied to the actuator by the read head by induction and data can be transferred.
The bit pattern read is compared with the code saved in the evaluation unit. If the
data match, the door monitoring output O1...O2 or O1...O4 (semiconductor output)
on the related read head is set HIGH. If all data for all read heads activated match,
the safety outputs (relay outputs) are then enabled. The OUT LED illuminates.
Before the system forms a function unit, the parameters are set in the evaluation
unit by the user (number of connected read heads, with or without automatic start,
with or without feedback loop). During this process the read heads are activated.
Due to the combination of dynamic polling of the actuators and the redundant,
diverse design of the safety electronics with two safety outputs, the evaluation
unit will enter the safe state with every detectable fault.
When a safety guard is opened, the safety outputs switch off the safety circuit and
the OUT LED goes out. The state of the safety outputs is monitored internally by
positively driven NC contacts (relay output).
Independent of the switching state of the safety circuit, the position of all safety
doors can be polled via the outputs O1...O2 or O1...O4.
If an internal fault occurs in the evaluation unit, the safety circuit is switched off,
the diagnostic output (DIA) is set HIGH and the DIA LED illuminates red.