•
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 also switch if
controlled with negative voltage (e.g., electro-mechanical contactor without
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 7: 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 appli‐
cable national regulations or required reliability of the safety function.
b
Make sure that downstream contactors are monitored (external device monitoring,
EDM).
Requirements for the electrical control of the machine
The OSSDs are short-circuit protected to 24 V DC and 0 V. When the safety locking
device is locked, the OSSDs signal the ON state with the HIGH signal level (non-iso‐
lated). If the safety locking device is unlocked or there is a device fault, the OSSDs sig‐
nal the OFF state with the LOW signal level.
4.4.3
Application diagnostic output
The application diagnostic output signal changes as soon as the actuator is moved into
or leaves the response range of the safety switch. In other words, it does so when the
moving protective device is opened and closed. This is not a safety output.
Actuator
Application diagnostic output
Actuator not in response range.
ON
Actuator in response range.
OFF
Table 1: Application diagnostic output switching behavior
4.4.4
Cascading
Cascading can be used to connect multiple safety locking devices. The connected devi‐
ces will provide the combined safety outputs and therefore act outwardly like one
device.
PROJECT PLANNING
4
8019972/2016-07-19 | SICK
O P E R A T I N G I N S T R U C T I O N S | TR10 Lock
15
Subject to change without notice