1756-RM001B-EN-P, Using ControlLogix in SIL2 ... - Tuv-fs.com

3-2 ControlLogix System HardwareControlLogix ChassisThe ControlLogix 1756-Axx chassis provide the physical connectionsbetween modules and the ControlLogix backplane. These connectionsallow for P/C communications between controllers and I/O modules.The chassis itself is passive and is not relevant to further discussionsince any physical failure would be unlikely under normalenvironmental conditions and would be manifested and detected as afailure within one or more of the active components.ControlLogix PowerSuppliesControlLogix power supplies are designed with noise filtering andisolation to reduce the opportunity for induced contamination of thesupplied voltages. The power supply monitors the backplane powerand generates control signals (for example, DC_FAIL_L) to indicate ifpower failure is imminent. Anomalies in the supplied voltagesimmediately shut down the power supply. The power supplymonitors all power supply voltages via sense lines.IMPORTANTNo extra configuration or wiring is required for SIL2operation of the ControlLogix power supplies.All ControlLogix power supplies are designed to:• detect anomalies• communicate to the controllers with enough stored power toallow for an orderly and deterministic shutdown of the system,including the controller and I/OPublication 1756-RM001B-EN-P - October 2003