IEC 61784-3-8:2010 pdf – lndustrial communication networks – Profiles – Part 3-8: Functional safety fieldbuses – Additional specifications for CPF 8.
denigrated synonym for DLPDU
hash function
(mathematical) function that maps values from a (possibly very) large set of values into a
(usually) smaller range of values
NOTE I Hash tunctone can be uBed to detect data corruptio4l.
NOTE 2 Conmon hash functions include parity, checksum or CRC.
(IECITR 82210. modifiedl
state or set of conditions of a system that, together with other related conditions will inevitably lead to harm to persons, property or environment
active communication entity able to initiate and schedule communication activities by other stations which may be masters or slaves
ordered series of octets intended to convey information (ISO/IEC 2382-16.02.01. modified)
p.rformanc. level (PL)
discrete level used to specify the ability of safety-related parts of control systems to perform a safety function under foreseeable conditions
(ISO 13849-1)
prot.ctlv. .xtra.low.voltag. (PELY)
electrical circuit in which the voltage cannot exceed ac. 30 V r.m.s., 42,4 V peak or d.c. 60 V In normal and single-fault condition, except earth faults in other circuits
NOTE A PEI.V c,rcuit , n,lar to an SELV c.rcu,i that , connected to protrctiv earth.
(IEC 61131-2)
r.d u ndancy
existence of means. In addition to the means whicti would be sufficient for a functional unit to perform a required function or for data to represent Information
NOTE Th. definition in 1EC 61508-4 lithe sanle, wvth additional esampi. and not…
(IEC 61508-4:2010. modifiedj, [ISO/IEC 2382.14.01.12, modified)
probability that an automated system can perform a required function under given conditions for a given time interval (tI .12)
NOTE I It Is generally assumed mat the aulomated system e In a state to perform this required function at the beginning of the time interval.
safety function response time
worst case elapsed time following an actuation of a safety sensor connected to a fieldbus, before the corresponding safe state of its safety actuator(s) is achieved in the presence of errors or failures in the safety function channel
NOTE This concept is introduced in IEC 81784.3:2010 7, 52.4 and addressed by the functional safety communication profiles defined In this part.
safety Integrity level (SIL)
discrete level (one out of a possible tour), corresponding to a range of safety integrity values. where safety integrity level 4 has the highest level of safety integrity and safety integrity level I has the lowest
NOTE I The target failure measures (see IEC 61508-4:2010. 3517) for the four safely inlegnty levets are sp.cifled en Tables 2 and 3 of IEC 6l5OB-1-2010,
NOTE 2 Safety integrity levels are used for specifying the safety integrity requirements of the safety functions to be allocated to the E?E(PE safety-relaled systems
NOTE 3 A safely integrity lvei (SIL) is not a proç.rty of a system, subsyst.m. element or component. The correct interpretation of the phrase StLn safety-rotated eystem (where fl is 1, 2. 3 or 4)15 that the system is potentially capable of supporting sf.ty functions with a safety integrity level up to n
[IEC 61508-4:2010j
safety measure