The following requirements are met:
•
The external voltage supply of the protective device must be capable of buffering
brief power failures of 20 ms as specified in IEC 60204-1.
•
The power supply unit must ensure safe isolation according to IEC 61140
(SELV/PELV). Suitable power supply units are available as accessories from SICK.
Further topics
•
4.4.1
Restart interlock
Overview
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.
Depending on the regulations which apply at the place of installation, a restart interlock
may be required.
The safety light curtain has an internal restart interlock.
Important information
DANGER
Hazard due to unexpected starting of the machine
The machine may not restart if the OSSDs switch to the ON state once the reset
pushbutton has been pressed. The control must ensure that the machine only restarts
if the machine start button is also pressed after the reset pushbutton.
b
Make sure that the machine can only restart once the reset pushbutton and start
button have been pressed in the specified order.
Principle of operation
Before the machine can be restarted, the operator must reset the restart interlock.
!
§
"
$
Figure 32: 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.
4.4.1.1
Integrated restart interlock and reset
Prerequisites
•
A reset device, such as a reset pushbutton, is connected.
4
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 | deTec4
8021645/1EB0/2022-04-28 | SICK
Subject to change without notice
