Planning the use
3.7 Requirements for fail-safe operation
KP8, KP8F, KP32F
Operating Instructions, 11/2011, A5E03284305-02
43
Proof-test interval
Note the following:
● They have a considerable safety responsibility for the instrumentation with sensors.
● Sensors normally do not survive a proof-test interval of 10 years corresponding with
IEC 61508.
The sensors clearly lose their safety.
Note
In order to reach the safety categories SIL2, PL d and category 3, high-quality sensors
are required. The sensors used must fulfill the standards EN 60947-5-1:2004 and
EN 60947-5-5:1997 (VDE 0660, section 200).
The contacts of the sensors must be weld-resistant in accordance with the standard
IEC EN 60947-5. Ensure that the sensor connection is free of short-circuits.
Define an ideal proof-test interval for the used sensor.
Fault detection
Faults can be detected if the following connection errors are present:
● Short-circuit between two sensors
● Short-circuit to DC 24 V
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)".
3.7.2 Sensor for 1oo2 mode
The following safety categories can be achieved with the HMI device:
● SIL3 corresponding to IEC 61508
● PL e corresponding to IEC 13849-1
● Category 4 according to EN 954
Note
Have the fail-safe part of the system checked and accepted by a registered company in
regards to the prescribed technical safety controls before commissioning the HMI device.
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