External Device Monitoring (Edm) - SICK deTec4 Core Operating Instructions Manual

4.4.2

External device monitoring (EDM)

8014253/YST2/2016-04-11 | SICK
Subject to change without notice
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.
Before the machine can be restarted, the operator must reset the restart interlock.
Figure 15: Schematic representation of operation with restart interlock
The dangerous state of the machine 1 is brought to an end if the light path is inter‐
rupted 2 and is not re-enabled 3 until the operator presses the reset pushbutton
located outside the hazardous area 4. 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.
The safety light curtain does not have an internal restart interlock. If required, a restart
interlock must therefore be implemented externally via the circuitry or the control, e.g.,
in connection with the SICK switching amplifier UE48-2OS/UE48-3OS.
Verification of the external switching elements (external device monitoring, EDM) must
be implemented depending on applicable national regulations or required reliability of
the safety function.
The external device monitoring (EDM) monitors the status of downstream contactors.
In order to use the external device monitoring, positively guided contactors must be
used to switch off the machine. If the auxiliary contacts of the positively guided contac‐
tors are connected to the external device monitoring, the external device monitoring
checks whether the contactors drop off when the OSSDs are switched off.
NOTE
Because the safety light curtain does not have integrated external device monitoring,
this must be implemented in the external control, if required.
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