5
Operating Instructions
Read Heads/Actuators CEM-A-…
Correct use
CEM-A series read heads are operated in combi-
nation with an evaluation unit in the system family
CES-A-…B or CES-AZ-…B. In this combination, the
read head CEM-A is an interlocking device with
electromagnetic guard locking without guard locking
monitoring (type 4). The coding level depends on
the evaluation unit used (unicode or multicode eval-
uation). The combination is not allowed to be used
as guard locking for personal protection according
to EN ISO 14119.
In combination with a movable guard and the
machine control, this system prevents dangerous
machine functions from occurring while the guard
is open. A stop command is triggered if the guard
is opened during the dangerous machine function.
This means:
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Starting commands that cause a dangerous ma-
chine function must become active only when the
guard is closed.
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Opening the guard triggers a stop command.
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Closing a guard must not cause automatic starting
of a dangerous machine function. A separate start
command must be issued. For exceptions, refer
to EN 12100 or relevant C-standards.
Before use, a risk assessment must be performed
on the machine, e.g. according to the following
standards:
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EN ISO 13849-1, Safety of machinery – Safety-re-
lated parts of control systems – Part 1: General
principles for design
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EN ISO 12100, Safety of machinery – General
principles for design – Risk assessment and risk
reduction
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IEC 62061, Safety of machinery – Functional
safety of safety-related electrical, electronic and
programmable electronic control systems.
Correct use includes observing the relevant require-
ments for installation and operation, e.g. according
to the following standards:
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EN ISO 13849-1, Safety of machinery – Safety-re-
lated parts of control systems – Part 1: General
principles for design
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EN ISO 14119, Safety of machinery – Interlocking
devices associated with guards – Principles for
design and selection
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EN 60204-1, Safety of machinery – Electrical
equipment of machines.
The read head must be used only in conjunction
with the designated actuator from EUCHNER. On
the use of different actuators or other connection
components, EUCHNER provides no warranty for
safe function.
The series CEM read head must be operated only
in combination with evaluation units in the system
family CES-A-…B or CES-AZ-…B. Please check this
in the “Combination options” table in the manual of
the evaluation unit used.
Important
:
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The user is responsible for the integration of the
device in a safe overall system. For this purpose,
the overall system must be validated, e.g. in
accordance with EN ISO 13849-2.
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Correct use requires observing the permissible
operating parameters (see technical data).
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If a data sheet is included with the product, the
information on the data sheet applies.
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The PL that can be achieved depends on the
evaluation unit used.
General safety precautions
Safety switches fulfill personal protection functions.
Incorrect installation or tampering can lead to fatal
injuries to personnel.
Check the safe function of the guard particularly
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after any setup work
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after the replacement of a system component
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after an extended period without use
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after every fault
Independent of these checks, the safe function of
the guard should be checked at suitable intervals
as part of the maintenance schedule.
WARNING
Danger to life due to improper installation or due
to bypassing (tampering). Safety components fulfill
a personal protection function.
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Safety components must not be bypassed,
turned away, removed or otherwise rendered
ineffective. On this topic pay attention in partic-
ular to the measures for reducing the possibility
of bypassing according to EN ISO 14119:2013,
section 7.
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The switching operation must be triggered only
by actuators designated for this purpose.
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Prevent bypassing by means of replacement
actuators (only for multicode evaluation). For this
purpose, restrict access to actuators and to keys
for releases, for example.
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Mounting, electrical connection and setup only
by authorized personnel possessing the following
knowledge:
- specialist knowledge in handling safety com-
ponents
- knowledge about the applicable EMC regu-
lations
- knowledge about the applicable regulations on
occupational safety and accident prevention.
Function
The CEM read head behaves like a CES read head
(see manual of the evaluation unit used). As soon
as the actuator reaches the operating distance of
the read head, a signal is sent to the evaluation unit.
CEM read heads additionally feature a solenoid to
produce the locking force. The guard locking is not
monitored.
Version with remanence
The guard locking is activated as soon as the
control voltage U
CM
is present (open-circuit current
principle).
The solenoid retains a slight residual magnetism
after it is switched off. This decreases over time.
This process is faster when the safety door is open
than when it is closed.
Version with remanence and permanent
magnet
A permanent magnet is installed in the CEM read
head with this version.
The guard locking is activated as soon as the control
voltage U
CM
is present (open-circuit current princi-
ple). After the solenoid switches off, the permanent
magnet’s attractive force acts between the CEM
read head and the magnetic mating plate of the
CEM actuator.
Version without remanence
The guard locking is activated when, in addition to
operating voltage U
B
, the control voltage U
CM
is
present (open-circuit current principle).
In particular during metal machining, the residual mag-
netism (remanence) in the guard locking solenoid can
cause problems. In the open state, metal chips may
be drawn to the contact area. The next time the guard
is closed, there will be a gap between the actuator
and read head that will limit the locking force. To avoid
this effect there are read heads without remanence.
These read heads are demagnetized when the sole-
noid is switched off. The operating voltage U
B
must
always be applied for this purpose.
LED
CEM devices with a locking force of 650 N feature
an integrated LED on plug connector X1.
An external LED can be connected to plug connector
X2 on devices with a locking force of 1,000 N.
The LED illuminates when the solenoid is energized.
Installation
NOTICE
Device damage due to improper mounting and
unsuitable ambient conditions
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Safety switches and actuators are allowed to be
used as an end stop. Observe the max. permis-
sible impact energy (see technical data).
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When the safety door is opened, the actuator
must be moved away from the read head toward
the front (see Figure 1).
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Observe EN ISO 14119:2013, sections 5.2 and
5.3, for information about fastening the safety
switch and the actuator.
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Observe EN ISO 14119:2013, section 7, for
information about reducing the possibilities for
bypassing an interlocking device.
Read head
Actuator
± 4°
Figure 1: Approach direction
Protection against environmental
effects
Dirt on the surfaces of the read head and actuator
can reduce the adhesive force and the locking force.
Clean the surfaces at regular intervals.
Cover the read head, the actuator and the type label
during painting work!
Electrical connection
NOTICE
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All the electrical connections must either be
isolated from the mains supply by a safety
transformer according to IEC EN 61558-2-6 with
limited output voltage in the event of a fault, or
by other equivalent isolation measures.
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If a common power supply is used, all the induc-
tive and capacitive loads (e.g. contactors) con-
nected to the power supply must be connected
to appropriate interference suppression units.
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For terminal assignment, see Figure 4.
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For detailed information, see the operating instruc-
tions for the evaluation unit used.
