I am currently developing a method for symbolically executing and testing IEC 61131-3 applications. For evaluating my approach, I require non-trivial programs written in any of the languages defined in the standard.
Are there any openly accessible code bases I could use for this?
The OSCAT libraries is the biggest open code base written in IEC61131-3 afaik. They provide different libraries for different use cases and for different plc vendors
Furthermore there are some example programs available on Beckhoff Infosys. For almost every library they provide a sample section. One of the biggest samples is the OOP extension sample (OOP extensions are included in the new version of IEC61131-3, not sure if you are interested in it).
Another source of examples is the Codesys Store. They have some free and some paid examples.
And one more I like (but its only in german). M. Seitz the author of a good plc programming book provides some accompanying samples, one of them a bit bigger (coffee machine). There is also a simulation and control library available.
A very good source for examples is Beckhoff's information system which is also available for download.
You can find good examples of different methods for example under different libraries.
Some links:
