For a single system, the reset pushbutton can be connected to the 5-pin system con‐
nection.
In a cascade, the reset pushbutton can be connected to the 5-pin system connection of
the host twin stick.
When the restart interlock is configured, the RES LED signals when the reset pushbut‐
ton needs to be pressed.
Further topics
•
4.4.3
External device monitoring (EDM)
Overview
The safety light curtain 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
•
Use positively guided contactors for shutting down the machine.
•
Connect the auxiliary contacts of the positively guided contactors to the external
device monitoring (EDM).
Operating principle
If external device monitoring is configured, the safety light curtain 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.
Pin 4
Pin 2
Pin 2
Pin 4
K1
k1
k2
K2
0 V DC
24 V DC
Figure 25: Electrical diagram of external device monitoring (EDM)
The external device monitoring must be implemented electrically so that the two N/Cs
(k1, k2) close in a positively guided manner when the contactors (K1, K2) reach their
de-energized position once the protective device has responded. 24 V are then present
at the input of external device monitoring. If 24 V are not present once the protective
device has responded, one of the contactors is defective and external device monitor‐
ing prevents the machine from restarting.
4
PROJECT PLANNING
34
O P E R A T I N G I N S T R U C T I O N S | miniTwin4
8012624/10OM/2018-08-09 | SICK
Subject to change without notice