【正文】 ..................................... 30 Combination of temporal and logical monitoring of program sequences ............... 30 Temporal monitoring with online check ................................................................ 30 Ventilation and heating ................................................................................................... ... 31 Temperature sensor .............................................................................................. 31 Fan control ............................................................................................................ 31 Actuation of the safety shutoff via thermal fuse.................................................... 31 Staggered message from thermosensors and conditional alarm.......................... 31 Connection of forcedair cooling and status indication .......................................... 31 Communication and massstorage ................................................................................... . 32 Separation of electrical energy lines from information lines .................................. 32 Spatial separation of multiple lines ........................................................................ 32 Increase of interference immunity ......................................................................... 32 Antivalent signal transmission .............................................................................. . 33 Sensors ................................................................................................................... .......... 33 Reference sensor.................................................................................................. 33 Positiveactivated switch ....................................................................................... 33 Final elements (actuators) ................................................................................................ . 33 Monitoring ...................................................................................................... ....... 33 Crossmonitoring of multiple actuators .................................................................. 34 Measures against the physical environment ...................................................................... 34 Annex B (informative) Overview of techniques and measures for E/E/PES: avoidance of systematic failures (see IEC 615082 and IEC 615083) .................................................................. 35 General measures and techniques .................................................................................... 35 Project management ............................................................................................. 35 Documentation ...................................................................................................... 36 Separation of safetyrelated systems from nonsafetyrelated systems ................ 37 Diverse hardware .................................................................................................. 37 Page 6 EN 61508?7:2020 Licensed Copy: Institute Of Technology Tallaght, Institute of Technology, Mon Jun 11 16:16:51 GMT+00:00 2007, Uncontrolled Copy, (c) BSI Clause Page E/E/PES safety requirements specification ....................................................................... 38 Structured specification ......................................................................................... 38 Formal methods ................................................................................................... . 38 Semiformal methods ............................................................................................ 39 General ................................................................................................. . 39 Finite state machines/state transition diagrams...................................... 39 Time Petri s ....................................................................................... 40 Computeraided specification tools ....................................................................... 40 General ................................................................................................. . 40 Tools oriented towards no specific method ............................................ 41 Model orientated procedure with hierarchical analysis ........................... 41 Entity models......................................................................................... . 41 Incentive and answer ............................................................................. 42 Checklists ............................................................................................................. 42 Inspection of the specification ............................................................................... 43 E/E/PES design and development.................................................................................... . 43 Observance of guidelines and standards .............................................................. 43 Structured design ................................................................................................. . 44 Use of welltried ponents ................................................................................ 45 Modularisation....................................................................................................... 45 Computeraided design tools ................................................................................ 46 Simulation ............................................................................................................. 46 Inspection (reviews and