Siemens SIMATIC ET 200AL, System Manual

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Applications of the F-I/O module
5.2 Digital output applications
Digital I/O module F-DI 4+F-DQ 2x24VDC/2A, 4xM12 (6ES7146-5FF00-0BA0)
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Equipment Manual, V1.0, 05/2021, A5E51082342-AA
Ensure that the following steps are accomplished:
•
Configure readback times that are sufficiently long to allow the channel's external
voltages to respond to process value changes and applied test patterns from the bit
pattern test. However, configuring readback times that are too long can cause your load
to physically respond to applied test patterns during dark tests.
• Verify that internal current limiting as described in the data sheet is sufficient in
combination with your 24 V DC supply. Consider whether additional current limits or fuses
are necessary. Refer to "Specifications" and "Connecting" in the ET 200AL distributed I/O
system system manual ( https://support.industry.siemens.com/cs/ww/en/view/89254965 ).
The module controls all output channels as 1oo2 with cross-diagnostics.
All applications shown are capable of reaching SIL 3/Cat. 4/PL e unless you have dark testing
disabled.
To reach Cat. 4, ensure that the following conditions are met:
•
The dark testing is enabled.
• The external contactors are SIL-rated with sense contacts.
• The diagnostics are within limits when you read the sense contacts back and confirm the
external contactor response in your program. Siemens recommends using an F-DI input
for sense contact and other safety diagnostic inputs.
Output 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- 2 Safety Integrity Level (SIL)/Category/Performance Level (PL) requirements
Application Type of actuator connection Achievable
SIL/Category/PL
Dark test disabled Dark test enabled
1 Directly-connected SIL-rated actuator 2/3/d 3/4/e
2 External contactors: Separate P and M
controlled contactors
2/3/d 3/4/e
3 External contactors: Parallel-connected
contactors between P and M
2/3/d 3/4/e
4 External contactors: Separate output
channels for each contactor
2/3/d 3/4/e
Refer to "Pin assignment (Page 19)" for further information on connector pin assignments.
Refer to "Disable Dark Test (max. SIL 2, Cat. 3, PL d)" in "DQ parameters (Page 32)" for
additional information on enabling and disabling dark testing.