•
T
he external voltage supply of the safety light curtain must be capable of jumper‐
ing a brief power failure 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,
see "Accessories", page 99.
4.4.1 Restart interlock
Overview
T
he safety light curtain has an internal restart interlock.
Depending 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.
Important information
DANGER
H
azard due to unexpected starting of the machine
The machine may not restart if the OSSDs switch to the ON state once the reset push‐
button 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
Be
fore the machine can be restarted, the operator must reset the restart interlock.
Figure 19: 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.
4.4.1.1 Integrated restart interlock and reset
Prerequisites
•
A r
eset device, such as a reset pushbutton, is connected.
4 P
ROJECT PLANNING
34
O P E R A T I N G I N S T R U C T I O N S | deTec4 Ex 8022883/2019-03-07 | SICK
Subject to change without notice
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