EUCHNER STMxxx - Manual (Page 4)

Operating Instructions Safety Switches STM...
Correct Use
Safety switches series STM are electromagnetic inter-
lock devices with guard locking.
In combination with a separating safety guard and the
machine control, this safety component prevents the
safety guard from being opened while a dangerous
machine movement is being performed.
For the control system, this means that
starting commands which cause hazardous situations
must become active only when the safety guard is in
protective position and the guard locking is in locked
position.
The locked position of the guard locking must be
released only when the hazardous situation is no longer
present.
Before safety switches are used, a risk assessment must
be performed on the machine in accordance with
EN ISO 13849-1, Safety of machinery. Safety related
parts of control systems. General principles for design
EN ISO 14121, Safety of machinery. Risk assessment.
Principles
IEC 62061, Safety of machinery – Functional safety of
safety-related electrical, electronic and programmable
electronic control systems
Correct use includes compliance with the relevant
requirements for installation and operation, particularly
EN ISO 13849-1, Safety of machinery. Safety related
parts of control systems. General principles for design
EN 1088, Safety of machinery. Interlocking devices
associated with guards. Principles for design and
selection
EN 60204-1, electrical equipment of machines
Important:
The user is responsible for safe 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.
If the simplified method according to section 6.3 EN
ISO 13849-1:2008 is used for validation, the Perfor-
mance Level (PL) may be reduced if several devices
are connected one after the other.
If a product data sheet is included with the product,
the information on the data sheet applies in case of
discrepancies with the operating instructions.
Safety Precautions
Safety switches fulfill a personal protection function.
Incorrect installation or tampering can lead to severe
injuries to personnel.
Safety components must not be bypassed (bridging
of contacts), turned away, removed or otherwise
rendered ineffective.
On this topic pay attention in particular to the measures
for reducing the possibility of bypassing according to
EN 1088:1995.A2:2008, sec. 5.7.
The switching operation may only be triggered by
actuators specially provided for this purpose which
are permanently connected to the protective guard.
Mounting, electrical connection and setup only by
authorized personnel.
Function
The safety switch permits the locking of movable safety
guards.
In the switch head there is a rotating cam that is blocked/
released by the guard locking pin. The guard locking pin
is moved on the insertion / removal of the actuator and
on the activation / deactivation of the guard locking.
During this process the switching contacts are actuated.
If the cam is blocked, the actuator cannot be pulled out
of the switch head guard locking active.
Position monitoring of the safety guard and monitoring
of interlocking are performed via two separate switching
elements.
Version STM1
(Guard locking by spring force)
The guard locking is held in locked position by a spring-
loaded pin and is released when voltage is applied to the
solenoid. The guard locking functions in accordance with
the closed-circuit current principle.
The safety guard cannot be opened immediately in the
event of interruption of the solenoid power supply.
Version STM2
(Guard locking by solenoid force)
This type must be used only in special cases after
strict assessment of the accident risk!
The safety guard can be opened immediately in the
event of interruption of the solenoid power supply!
The guard locking is held in the locked position by an
electromagnetically actuated pin and released by spring
force. The guard locking operates in accordance with
the open-circuit current principle.
Close safety guard and activate guard locking
The guard locking pin is released by insertion of the
actuator into the safety switch.
STM1: The guard locking pin is moved to locked position
by spring force.
STM2: The guard locking pin is moved to locked position
when the solenoid operating voltage is applied.
Door safety circuit SK and monitoring circuit ÜK are
closed.
Deactivating guard locking, opening safety guard
STM1: The guard locking pin releases the cam when the
solenoid operating voltage is applied.
The monitoring circuit is opened.
For switching function see Figure 2 column 2 Door closed
and not locked
The actuator can be removed.
Safety circuit SK is positively opened and blocked in this
position when the actuator is removed. This signals that
the safety guard is open (see Figure 2 column 3,
Door
open).
STM2: The guard locking pin releases the cam when the
solenoid operating voltage is switched off.
The monitoring circuit is opened.
For switching function see Figure 2 column 2 Door closed
and not locked
The actuator can be removed.
Safety circuit SK is positively opened and blocked in this
position when the actuator is removed. This signals that
the safety guard is open (see Figure 2 column 3,
Door
open).
Mechanical Release
In the event of malfunctions, the guard locking can be
deactivated using the mechanical release, irrespective
of the state of the solenoid (see Figure 3).
Unscrew locking screw.
Using a screwdriver, turn the mechanical release by
approx. 180° in the direction of the arrow.
The locking screw must be returned to its original position
and sealed after use (for example with sealing lacquer).
Installation
Safety switches and actuators must not be used as
an end stop.
Mount the safety switch only in assembled condition!
Caution! Risk of burns due to high surface
temperature at ambient temperatures above 40 °C!
Protect switch against touching by personnel or
contact with inflammable material.
Assemble the safety switch so that
access to the switch is difficult for operating personnel
when the safety guard is open.
it is possible to operate the mechanical release and
check and replace the safety switch.
the escape release can be actuated from the hazard
area.
Fit an additional end stop for the movable part of the
safety guard.
Insert the actuator in the actuating head.
Mount the safety switch positively.
Permanently connect the actuator to the safety guard
so that it cannot be detached, e.g. using the enclosed
non-removable screws, rivets or welding.
Changing the Actuating Direction
Fig. 1: Changing the actuating direction
Remove the screws from the actuating head.
Insert the actuator in the actuating head.
Set the required direction.
Tighten the screws with a torque of 0.6 Nm.
Cover the unused actuating slots with the enclosed
slot covers.
Protection Against Environmental Influences
A lasting and correct safety function requires that the
actuating head must be protected against the penetration
of foreign bodies such as swarf, sand, blasting shot etc.
Cover the actuating slot, the actuator and the rating plate
during painting work!
Electrical Connection
When choosing the insulation material and wire for
the connections, pay attention to the over-
temperature in the housing (depending on the
operating conditions)!
Only switching contacts marked with the positively
driven NC contact symbol
are to be used for the
safety circuit.
For use and applications as per the requirements
of
, a class 2 power supply or a class 2
transformer according to UL1310 or UL1585 must
be used. As an alternative, a low voltage power
supply according to UL508 table 32.1 can be used.
Connection cables for safety switches installed at the
place of use must be separated from all moving and
permanently installed cables and un-insulated active
elements of other parts of the system which operate at
a voltage of over 150 V. A constant clearance of 50.8
mm must be maintained. This does not apply if the
moving cables are equipped with suitable insulation
materials which possess an identical or higher dielectric
strength compared to the other relevant parts of the
system.
The operating voltage for the interlocking solenoid must
match the value on the rating plate (e.g. U
S
= AC/DC 24 V).
Solenoid
SK ÜK
E1 E2
Safety guard closed, actuator
locked
B