IEC 61784-3-8:2016 specifies a safety communication layer (services and protocol) based on CPF 8 of IEC 61784-1, IEC 61784-2 and IEC 61158 Type 18 and Type 23. It identifies the principles for functional safety communications defined in IEC 61784-3 that are relevant for this safety communication layer. This safety communication layer is intended for implementation in safety devices only. This second edition cancels and replaces the first edition published in 2010. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: - Added FSCP 8/2; - Added FSCP 8/2 Clause 12; - Added content for FSCP 8/2 to Clauses 1 to 3 (scope, references, terms); - Moved previous FSCP 8/1 to Clause 11 (demoting all old heading levels by one); - Restructured old Clauses 4 to 10 to point to appropriate subclauses as appropriate.