Notes On Wiring - Pilz PSS Series Operating Manual

Wiring the Inputs and Test Pulse Outputs

Notes on wiring

Where safety-related applications are concerned, it is essential that short
circuits and open circuits are unable to cause a hazardous condition within
a plant.
The way in which this is done will depend on the degree of hazard within
the plant itself, the switching frequency of the input devices and the level
of safety of the input devices and actuators. You should assess these
points in conjunction with the relevant standards or approvals body (e.g.
BG or TÜV).
Please observe the following when wiring:
• Earthing:
- Connect the housing to the central earth bar.
- A cable cross section of at least 2.5 mm
- Connections should be kept as short as possible.
• Open circuits, short circuits and earth faults:
- In principle it is possible to eliminate short circuits between signals
within electrically-enclosed areas and also outside electrically-enclosed
areas when the signals are conducted in different multicore cables.
However, all components must meet the relevant regulations in
accordance with EN, DIN and VDE.
- Open circuits and earth faults cannot be eliminated.
- On multi-channel input devices with frequent operation, short circuits
and open circuits can be detected via feasibility checks in the control
program.
- The input test on the programmable safety system uses test pulses to
enable the system's operating program to carry out a test to detect
open circuits and short circuits.
NOTICE
Please read the description that accompanies the connection
examples! The connection examples can be found on the following
pages.
7-2
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2 should be used.
Operating Manual: PSS SB 3006-3 Series