Principle of operation
If you configure external device monitoring, the safety light curtain then checks the
contactors after every interruption to the light path and before the machine restarts.
External 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
r
Figure 34: Electrical diagram of external device monitoring (EDM)
You must implement external device monitoring 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.
4.4.3
Application diagnostic output
The safety light curtain has an application diagnostic output on the system connection
and on the extension connection.
Depending on the configuration, the application diagnostic output signals a certain
status of the safety light curtain, e.g. if the reset pushbutton must be engaged or if
there is a weak signal at the receiver.
For a signal of the safety light curtain to be displayed, a light can be connected to
the application diagnostic output or the signal can be transmitted to the machine
controller.
0 V DC
ADO
r
Figure 35: Electrical diagram of the application diagnostic output
Further topics
•
"Configuring application diagnostic output", page 105
4.4.4
Signal lamp
Overview
You can attach an external signal lamp to the system to indicate muting or Smart Box
Detection.
During operation, the signal lamp indicates temporary muting or the detection of a valid
object by Smart Box Detection.
4
PROJECT PLANNING
58
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
