AS IEC 61131.6:2014 Programmable controllers
5.2.1 General
Prior to entering the realization phase, the functional safety and safety integrity requirements, defining the FS-PLC logic functions and their SIL capability, shall be stated. Then, there needs to be an allocation of the functional safety and SIL capability requirements to either hardware, software or both. This leads to detailed requirements for hardware and software as specified in Clauses 9 and 1 0, respectively.
The hardware and software lifecycle phases applied in this part are:
– FS-PLC design requirements specification [box 1 of Figure 3; Clause 6]
– Design, development and validation plan [box 2 of Figure 3; Clause 7]
– FS-PLC architecture [box 3 of Figure 3; Clause 8]
– SW safety architecture [box 4 of Figure 3]
– HW safety architecture [box 5 of Figure 3]
– Safety validation plan [box 6 of Figure 3; Clause 1 1 ]
– HW safety function and safety integrity requirements [box 7 of Figure 3]
– SW safety function and safety integrity requirements [box 8 of Figure 3]
– Programmable & non-Programmable HW requirements [box 9 of Figure 3]
– Engineering tools and embedded SW requirements [box 1 0 of Figure 3; Subclause 1 0.3]
– Programmable & non-programmable HW safety validation planning [box 1 1 of Figure 3]
– Engineering tools & embedded SW safety validation planning [box 1 2 of Figure 3;Subclause 1 0.4]
– Programmable & Non-Programmable HW design & development [box 1 3 of Figure 3]
– Engineering tools & Embedded SW design & development [box 1 4 of Figure 3; Clause 1 0]
– HW Validation [box 1 5 of Figure 3; Subclause 9.7]
– SW Validation [box 1 6 of Figure 3]
– Programmable & non-programmable HW operation & modification procedure [box 1 7 of Figure 3; Clause 1 5]
– Engineering tools & embedded SW operation & modification procedure [box 1 8 of Figure 3]
– HW – Embedded SW integration [box 1 9 of Figure 3; Subclause 9.5]
– FS-PLC integration [box 20 of Figure 3]
– FS-PLC safety validation [box 21 of Figure 3; Clause 1 1 ]
5.2.2.1 General
Security threat and hazard analysis are normally necessary for safety-related applications to protect against intentional attacks or unintentional changes. Security can be achieved by establishing appropriate security policies and measures such as physical (for example mechanical, electronic) or organizational measures.
Where safety related communications are part of the FS-PLC there is the possibility of inadvertent changes to the parameters of network devices. Safety related communication devices shall have protections against inadvertent changes.
Where applicable, the requirements for overall security defined in IEC 62443 shall be followed.