4.4.1 Restart interlock
Overview
D
epending on the regulations which apply at the place of installation, a restart interlock
may be required.
The restart interlock prevents the machine from automatically starting up, for example
after a protective device has responded while the machine is operating or after chang‐
ing the machine’s operating mode.
The safety light curtain does not have an internal restart interlock. If required, a restart
int
erlock must therefore be implemented externally via the circuitry or the control, e.g.,
in connection with the SICK switching amplifier UE48-2OS/UE48-3OS.
Principle of operation
Before the machine can be restarted, the operator must reset the restart interlock.
Figure 18: Schematic representation of operation with restart interlock
T
he dangerous state of the machine (!) is brought to an end if the light path is inter‐
rupted (") and is not re-enabled (§) until the operator presses the reset pushbutton
located outside the hazardous area ($). The machine can then be restarted.
Depending on the applicable national regulations, there must be a restart interlock if a
person can stand behind the protective field. Observe IEC 60204-1.
4.4.2 External device monitoring (EDM)
Overview
T
he external switching elements (external device monitoring, EDM) must be inspected
in line with the regulations which apply at the place of installation or the required relia‐
bility of the safety function.
The external device monitoring (EDM) monitors the status of downstream contactors.
Important information
NOTE
Bec
ause the safety light curtain does not have integrated external device monitoring,
this must be implemented in the external control, if required.
Prerequisites
•
Positively guided contactors are used for shutting down the machine.
If the auxiliary contacts of the positively guided contactors are connected to the
external device monitoring, the external device monitoring checks whether the
contactors drop off when the OSSDs are switched off.
PROJECT PLANNING 4
8024467/2019-06-18 | SICK O P E R A T I N G I N S T R U C T I O N S | deTec4 Core Vibes
27
Subject to change without notice
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