
Rockwell Automation Publication 1756-RM001I-EN-P - May 2012
65
FLEX I/O Modules
Chapter 6
Figure 36 - ControlLogix/FLEX I/O Standard Output Module Wiring with an Isolated Relay Module
Using Analog Input Modules
To achieve SIL 2, two analog input modules are required. Field sensors must be
wired to channels on each module and compared within a deadband. Whether
one or two field sensors are required is dependent on the Probability of Failure on
Demand (PFD) value of the sensor.
Requirements When Using FLEX I/O Analog Input Modules
You must follow these general application considerations when applying these
modules in a SIL2 application:
• Proof tests.
Periodically (for example, once every several years) a System
Validation test must be performed. Manually, or automatically, test inputs
to make sure that all inputs are operational. Field signal levels should be
varied over the full operating range to make sure that the corresponding
channel data varies accordingly.
1 2
3 4 5
6 7
8 9 10 11 12 13 14 15
0
24VDC SINK INPUT
1794-IB16
1 2
3 4 5
6 7
8 9 10 11 12 13 14 15
0
24VDC SOURCE OUTPUT
1794-OB16
1 2
3 4 5
6 7
8 9 10 11 12 13 14 15
0
24VDC SOURCE OUTPUT
1794-OB16
Isolated Relay Output
Module
43364
Standard Digital
Input Module
Standard Digital
Output Module
+24V
COM
Wire output point to
input point to verify
the correct state of the
output.
Output
Output
Actuator
+24V
COM
Note 1: An external relay can be replaced with an isolated relay module which is mounted in another FLEX I/O rail.
Summary of Contents for 1756-L6 Series
Page 24: ...24 Rockwell Automation Publication 1756 RM001I EN P May 2012 Chapter 1 SIL Policy Notes ...
Page 76: ...76 Rockwell Automation Publication 1756 RM001I EN P May 2012 Chapter 6 FLEX I O Modules Notes ...
Page 126: ...126 Rockwell Automation Publication 1756 RM001I EN P May 2012 Appendix D Checklists Notes ...
Page 133: ...Allen Bradley Motors ...