Siemens SIRIUS 3RK3 - Connecting Safety-Related Inputs

5.3.2.3 Connecting safety-related inputs
Single- and two-channel sensors
To achieve the required performance level or SIL, single-channel or two-channel interconnection
of the inputs of the MSS 3RK3 is possible. The following connection options are available:
• In the case of single-channel connection, only one input terminal is assigned for each sensor.
• In the case of two-channel connection, two input terminals are assigned for each sensor.
Both single-channel and two-channel sensors can be interconnected on a single 3RK3 central
unit or expansion module. The number of connectable sensors thus varies according to the
connection options. Up to 4 two-channel sensors or 8 single-channel sensors can be
connected to the 3RK3 central unit.
• The safety-related inputs can also be used to read standard signals (non-safety-related).
• Cross-circuit detection is possible when the test outputs are used with two-channel sensors.
Note
Non-󹪞oating sensors
When sensors with non-󹪞oating outputs (e.g. light curtains, laser scanners) are used, they
must not be supplied with power via test outputs T1_x/T2_x. Cross-circuit detection of the
applicable function element must be deactivated in Safety ES.
Connection options with test output
2 single-channel sensors 1 two-channel sensor*
)
Single-channel and two-channel sen‐
sor mixed*
)
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7
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T1 test output for IN1, 3, 5, 7
T2 test output for IN2, 4, 6, 8
IN1 ... IN5 sensor inputs
*
)
Two-channel sensors are monitored for cross-circuits
Description of the hardware
5.3 Connecting / wiring
SIRIUS 3RK3 Modular Safety System
138 Equipment Manual, 07/2020, NEB926253002000/RS-AC/006