
Safety engineering
Device modules
Safe inputs
32
EDS94AYAF EN 1.0
1.2.5.2
Connection of passive sensors
The safe sensor inputs I1A ... I4B are suitable for
equivalently switching
passive sensors.
To monitor passive sensors according to EN ISO 13849−1, cat. 3 or cat. 4, the clock outputs
CLA and CLB must be wired. Please observe the following:
ƒ
The clock outputs are only suitable for monitoring the passive sensors.
ƒ
Always connect ...
– ... CLA to IxA (channel A of the sensor input) via the sensor.
– ... CLA to IxB (channel B of the sensor input) via the sensor.
– ... GCL with GIx of the sensor input.
ƒ
The sensor inputs are tested cyclically through short LOW operation.
– The A and B channels are tested at different times in cycles of approx. 2 s, with
test pulses of < 1 ms.
These errors are detected:
ƒ
Short circuit to supply voltage.
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Short circuit between the input signals when different clock outputs are used.
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Non−equivalent input signals after the discrepancy time.
These errors are not detected:
ƒ
Short circuit between the input signals when the same clock outputs are used.
Note!
Avoid unrecognisable errors by the installation, e.g. by separated cable routing.
GCL
GI2
I2B
I2A
GCL
GI1
I1A
I1B
CLB
CLA
S1
S2
V
CC
û
û
SM30x
E94AYAx
SSP94SM351
Fig. 1−8
Ways to detect errors
û
Unrecognisable errors