ABB AC500-S Application Note

Also see for AC500-S: System manual Safety user manual Safety user manual Operation manual

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ABB AC500-S Application Note Manual pdf 20 page image

Application Note for “Usage of AC500 digital standard I/Os in functional safety applications up to PL c (ISO 13849-1)”, V1.0.0Page 20/24We reserve all rights in this document. Reproduction, use or disclosure to third parties without express authority is strictly forbidden. Ó 2015 ABB Ltd.3.4.4 Safety function response timeSFRT calculation shall be done based on the data presented in Chapter 5 [1]. It isstraight-forward for all functional safety modules, like SM560-S and DX581-S, but re-quire additional analysis for standard (non-safety) ones, like PM573 and DC523.Under assumptions and implementation aspects listed in Chapter 3.4.1, one can addthe following fault error reaction time (e.g., for Stuck-At-1 errors) for DC523 input chan-nel:- 400 ms, if supervised as proposed in Chapter 3.4.1.As for SFRT input part (it means SFRT up to SM560-S Safety CPU only), one shalladd the fault error reaction time for DC523 path (400 ms in the given example, refer toChapter 3.4.1) to a LOW phase supervision time (35 ms in the given example, refer toChapter 3.4.1) as the overall worst-case response time, which will result in SFRT forinput part:- 435 ms, if supervised as proposed in Chapter 3.4.1DANGERYou still have to do a complete SFRT calculation for the safetyloop(s) (not only input part but also logic processing and outputparts) in your application (see Chapter 5 [1]).3.5 Calculation of the probability of failure and correspondence toPL (ISO 13849-1)For calculation of the probability of failure for Safety PLC part, we will use ABB FSDTsoftware (see www.abb.com). Our goal is to confirm that PFHavg is (refer to Figure 7)below or equal to 15% of PL c for Category 2 (refer also to PFHavg values listed inTable K1 of ISO 13849-1 for given Category, DC and MTTFd values).