Figure 18: Dual-channel and isolated connection of OSSD1 and OSSD2
•
The machine must switch to the safe state at any time if at least one of the two
OSSDs switches to the OFF state.
•
Prevent the formation of a potential difference between the load and the protec‐
tive device. If you connect loads to the OSSDs (safety outputs) that then also
switch if controlled with negative voltage (e.g., electro-mechanical contactor with‐
out reverse polarity protection diode), you must connect the 0 V connections of
these loads and those of the corresponding protective device individually and
directly to the same 0 V terminal strip. In the event of a fault, this is the only way to
ensure that there can be no potential difference between the 0 V connections of
the loads and those of the corresponding protective device.
Figure 19: No potential difference between load and protective device
DANGER
Hazard due to unexpected starting of the machine
A restart interlock must be implemented depending on applicable national regulations
or required reliability of the safety function.
b
Make sure that a restart interlock is implemented.
4
PROJECT PLANNING
36
O P E R A T I N G I N S T R U C T I O N S | deTem4 A/P
8024782/2019-11-19 | SICK
Subject to change without notice