Allen-Bradley 1756-L61S

Rockwell Automation Publication 1756-RM093J-EN-P - April 2018 103
Appendix G
Using 1794 FLEX™ I/O Modules and 1756 SIL 2
Inputs and Outputs with 1756 GuardLogix
Controllers to Comply with EN 50156
Dual-channel configuration is required for compliance in certain safety-related
applications, including burner-related safety functions. These examples provide
guidelines for satisfying EN50156 SIL 2 dual-channel requirements with 1- and
2-year proof test intervals.
SIL 2 Dual-channel Inputs
(standard side of 1756
GuardLogix controllers)
You must implement clear and easily-identifiable separation between both input
channels and adhere to all existing SIL 2 requirements as defined in Using
ControlLogix® in SIL 2 Applications, publication 1756-RM001
.
Figure 27 - SIL 2 Dual-channel Inputs Example F
Topic Page
SIL 2 Dual-channel Inputs (standard side of 1756 GuardLogix controllers) 103
SIL 2 Outputs Using SIL 3 Guard I/O Output Modules 105
SIL 2 Outputs Using 1756 or 1794 SIL 2 Output Modules 105
Safety Functions within the 1756 GuardLogix Safety Task 106
Channel A Channel B
Ch0+ Ch0+
Ch0- Ch0-
Voltage
Transmitter A
Voltage
Transmitter B
+
+
-
-