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

SIL Policy 1-5IMPORTANTThe system user is responsible for:• the set-up, SIL rating and validation of anysensors or actuators connected to theControlLogix control system.• project management and functional testing.• programming the application software and themodule configuration according to thedescription in the following chapters.The SIL2 portion of the certified system excludes thedevelopment tools and display/human machineinterface (HMI) devices; these tools and devices arenot part of the run time control loop.Proof TestsIEC 61508 requires the user to perform various proof tests of theequipment used in the system. Proof tests are performed atuser-defined times (for example, proof test intervals can be once ayear, once every two years or whatever timeframe is appropriate) andinclude some of the following tests:• Testing of all fault routines to verify that process parameters aremonitored properly and the system reacts properly when a faultcondition arises.• Testing of digital input or output channels to verify that they arenot stuck in the ON or OFF state.• Calibration of analog input and output modules to verify thataccurate data is obtained from and used on the modules.IMPORTANTUsers’ specific applications will determine thetimeframe for the proof test interval.However, keep in mind that the Probability ofFailure on Demand (PFD) calculations listed inTable 1.3 on page 1-10 use a proof test interval ofonce per year. If the proof test interval is changed,the information must be recalculated.For sample PFD calculations for proof test intervalsof 2 and 4 years, see Appendix EFor more information on system proof tests, see Chapter 2, TheControlLogix System. For more information on the necessary I/Omodule proof tests, see Chapter 6, ControlLogix I/O Modules.Publication 1756-RM001B-EN-P - October 2003