Planning the use
3.7 Requirements for fail-safe operation
KP8, KP8F, KP32F
Operating Instructions, 11/2011, A5E03284305-02
45
Fault detection
Faults can be detected if the following connection errors are present:
● When non-equivalent sensor signals are connected.
● When a single-channel sensor has a redundant connection.
WARNING
No redundant connection of two single-channel break contacts
If sensor signals are connected redundantly (break contacts), a fault will only be
recognized if one of the sensors is triggered.
Ascertain that under no circumstances are two single-channel break contacts
redundantly connected as sensor signals.
Signal duration
In order to assure accurate detection of the sensor signal by the HMI device, you must
ensure that the minimum duration for the sensor signal is adhered to. See section "Technical
spec
ifications (Page 107)". The minimum duration is ensured by the usage of push-to-lock
emergency stop buttons.
3.7.3 Cables
The cables used must meet the following requirements:
● The unique assignment of terminals to sensors must be ensured.
● Cables laid outside of the switching cabinet must be laid separately in accordance with
the relevant standards.
Use stable pipes or cable channels in order to avoid short circuits and cross-circuits.
Note
With the connection of an emergency stop button to the fail-safe channels of the HMI
device, the line lengths corresponding with chapter "Technical specifications (Page 107)"
must be com
plied with.