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!
§
"
$
Figure 16: Schematic representation of operation with restart interlock
The 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 applicable national regulations, a restart interlock must be available if it
is possible to stand behind the protective device. Observe IEC
60204-1.
4.4.2
External device monitoring (EDM)
Overview
The 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
reliability of the safety function.
External device monitoring (EDM) monitors the status of downstream contactors.
Important information
NOTE
Because 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.
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PROJECT PLANNING
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O P E R A T I N G I N S T R U C T I O N S | C4-RD
8025644/19Z2/2021-03-09 | SICK
Subject to change without notice