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The following applies to the restart interlock:
•
If the protective device is clear once the machine has been switched on or follow‐
ing an interruption, the OSSDs do not switch to the ON state
•
The protective device changes to the reset required state after the light path
becomes clear, a lockout status or after a configuration change
•
If someone presses the reset pushbutton and then lets go of it when the light path
is clear, the OSSDs switch to the ON state
•
The machine may not restart yet. The operator must also press the machine start
button after having pressed the reset pushbutton.
Facilities for connecting
Only one reset pushbutton is allowed to be connected to the active unit of a multiple
light beam safety device.
Facilities for connecting of the reset button on the active unit:
•
M12, 8-pin system connection
•
Extension connection
Further topics
•
"Configuring the restart interlock", page 71
4.4.2
External device monitoring (EDM)
Overview
The multiple light beam safety device has internal external device monitoring.
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 relia‐
bility of the safety function.
The external device monitoring (EDM) monitors the status of downstream contactors.
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.
Functionality
If you configure external device monitoring, the protective device then checks the con‐
tactors after every interruption to the light path and before the machine restarts. Exter‐
nal device monitoring is then able to detect if one of the contactor’s contacts is welded,
for instance. In this case, the OSSDs remain in the OFF state.
24 V DC
k2
k1
K1
K2
0 V DC
OSSD 1
EDM
OSSD 2
Figure 22: Electrical diagram of external device monitoring (EDM)
PROJECT PLANNING
4
8024782/2019-11-19 | SICK
O P E R A T I N G I N S T R U C T I O N S | deTem4 A/P
39
Subject to change without notice