Figure 12: 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 (output signal switching devices)
that then also switch if controlled with negative voltage (e.g., electro-mechanical
contactor without reverse polarity protection diode), you must connect the 0 V con‐
nections of these loads and those of the corresponding protective device individu‐
ally 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 con‐
nections of the loads and those of the corresponding protective device.
Figure 13: No potential difference between load and protective device
DANGER
Hazard due to lack of effectiveness of the protective device
In the case of non-compliance, it is possible that the dangerous state of the machine
may not be stopped or not stopped in a timely manner.
Downstream contactors must be positively guided and monitored depending on applic‐
able national regulations or required reliability of the safety function.
b
Make sure that downstream contactors are monitored (external device monitoring,
EDM).
b
Because the multiple light beam safety device does not have integrated external
device monitoring, this must be implemented in the external control, if required.
PROJECT PLANNING
4
8021554/14Q7/2020-04-27 | SICK
O P E R A T I N G I N S T R U C T I O N S | deTem2 Core IP69K
21
Subject to change without notice