Ripley is a prototype of a Programmable Logic Controller (PLC) Emulator.
The idea was to have a leightweight emulator available in contrast to the big standalone commercial ones like SIEMENS plant simulation. See handbook_German.txt for details.
The project was discontinued in favour of an other approach based on the idea of writing test scripts using xUnit like test functions.
The technology used for Ripley is Node.js for the backend and jQuery for the fronted. Time of development was around 2012.