References and standards

Short term	Long term; publisher. Explanation.
IEC 61131-3:2013	standard IEC 61131-3 Edition 3.0 2013-02, "Programmable controllers – Part 3: Programming languages". Standard dealing with basic software architecture and programming languages of the control program within PLC.
IEC 61508:2010	standard IEC 61508 Edition 2.0 2010-04, "Functional safety of electrical/electronic/programmable electronic safety-related systems Safety standard that describes the basic, complete lifecycle of safety-related systems.
ISO 13849-1:2015	standard ÖNORM EN ISO 13849-1 Edition: 2016-06-15, "Safety of machinery – Safety-related parts of control systems, Part 1: General principles for design" Safety standard which applies to parts of machinery control systems that are assigned to providing safety functions.
ISO 26262:2018	standard ISO 26262 second edition 2018-12, "Road vehicles – Functional safety". International standard for functional safety of electrical and/or electronic systems in road vehicles.

Moreover, the following reference is valid:

Short term	Long term. Explanation.
logi.CAD 3 documentation	logi.CAD 3 user documentation; published by logi.cals. The user documentation on logi.CAD 3 describing the elements and usage of logi.CAD 3. An online edition is available under: https://help.logicals.com/
logi.µSRTS safety manual	logi.µSRTS safety manual; published by logi.cals. The safety manual for logi.µSRTS describing the intended usage of logi.µSRTS in a safety system.