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

6-6 ControlLogix I/O ModulesWiring ControlLogix DigitalInput ModulesThe wiring diagrams in Figure 6.3 show two methods of wiring thedigital input Module. In either case, users must determine whetherthe use of 1 or 2 sensors is appropriate to fulfill SIL2 requirements.Figure 6.3 ControlLogix Digital Input Module Wiring+ LineOne-Sensor Wiring ExampleInput A1Input B1SensorOptional Relaycontact toswitch linevoltage forperiodicautomatedtestingInput A2Input B2Two-Sensor Wiring ExampleSensorSensor43366Application logic can compare input values or states for concurrence.Figure 6.4Input AInput BActuatorThe user program must also contain rungs to annunciate a fault in theevent of a sustained miscompare between two points.Figure 6.5Input AInput BTimerInput ATimer DoneFaultInput BTimer preset in milliseconds tocompensate for filter time andhardware delay differences.FaultAlarm to OperatorThe control, diagnostics and alarming functions must be performed insequence. For more information on faults, see Chapter 7, Faults in theControlLogix System.Publication 1756-RM001B-EN-P - October 2003