Siemens SIMATIC ET 200AL, System Manual

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Applications of the F-I/O module
5.1 Digital input applications
Digital I/O module F-DI 4+F-DQ 2x24VDC/2A, 4xM12 (6ES7146-5FF00-0BA0)
Equipment Manual, V1.0, 05/2021, A5E51082342-AA
41
Input architectures for achieving Safety Integrity Level (SIL)/Category/Performance Level (PL)
The following are the minimum conditions which must be met for achieving the
corresponding safety requirements:
Table 5- 1 Safety Integrity Level (SIL)/Category/Performance Level (PL) requirements
Application Sensor
supply
1
Sensor
evaluation
Channel
connection
Type of sensor
connection
Achievable
SIL/Category/PL
Without
short-
circuit
detection
With
short-
circuit
detection
1 Internal 1oo1
evaluation
Single input 1 channel 2/3/d
2 External
3 Internal 1oo2
evaluation
Two inputs 2 channel
equivalent
3/3/e 3/4/e
4 External 3/3/e
5 Internal 2 channel - 3 wire
nonequivalent
3/3/e 3/4/e
6 External 3/3/e
7 Internal 2 channel - 4 wire
nonequivalent
3/3/e 3/4/e
8 External 3/3/e
1
The F-DI 4/F-DQ 2 Fail-Safe module uses M12 I/Oconnections and is intended for use outside a
cabinet in IP67 applications (everything sealed). If you require the use of an external supply, cut the
M12 cable and make the connection inside a sealed cabinet or inside a sealed sensor. For external
supplies, do not connect the pin 1 wire (V
S1
) or the pin 5 wire (V
S2
) in the M12 cable. This action
prevents the sensor supply (which may be ON due to a different channel being configured as inter-
nal) from being shorted to the external 24 V DC. In addition, make the external 24 V DC connection
inside a sealed cabinet or inside a sealed sensor.
Refer to "Pin assignment" (Page 19) for further information on connector pin assignments.
5.1.1 Applications 1 and 2: 1oo1 evaluation of single-channel sensors
F-DI application mode 1
This application mode uses single-channel sensors with a 1oo1 evaluation as shown in the
following illustrations. When you use an internal sensor supply, you can successfully perform
short-circuit detection.
Note
To incorporate F-DI application mode 1 into a SIL 2-rated application, ensure the sensors are
appropriately qualified devices.