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6
Actuator
Achievable
SIL/SIL CL/Cat./PL
External errors that can be
detected
Errors that cannot be
detected
External wiring
requirements
6-14
OUT0_Ch2_13
OUT0_Ch2_14
UT1 (UT2)
IN1 (IN2)
UT2 (UT)
IN2 (IN1)
K1 (R) and K2 (R) represent the forcibly guided N/C contacts for monitoring the state of the
relay (readback contacts).
To use the function for external contact monitoring, wire the N/C contacts to the alarm input
IN1 and IN2 as illustrated. In this case, the alarm inputs must be assigned to the outputs.
Parallel connection of the alarm contacts is not permitted.
These contacts can also be read via safe digital inputs. In this case, evaluate the readback
and thus the state of the actuators in your safe application program.
When calculating the SIL values for both alternatives, take the different failure rates into
consideration.
WARNING: Loss of the safety function due to external supply
Make sure that no cross circuits can occur.
Basic specifications
Two-channel
SIL 3/SIL CL 3/Cat. 4/PL e
If alarm inputs IN1 and IN2 are used:
1.
An external load does not pick up
2.
An external load does not drop out
If no alarm inputs are used, no errors can be detected in the external load or in the wiring.
The user is responsible for error analysis for the connected loads and for the external
wiring.
User manual IC220SDL840 - May 2018
Output 0, channel 2, contact 13
Output 0, channel 2, contact 14
Clock output UT1 or UT2
Alarm input IN1 or IN2
Clock output UT2 or UT1
Alarm input IN2 or IN1
GFK-2734
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