S7 AWL/STL Soft-PLC
Awlsim is a free Step 7 compatible AWL/STL Soft-PLC written in Python.
Depending on the host machine and the Python interpreter used, it achieves good performance of several thousand to millions of AWL/STL instructions per second. German and english AWL/STL mnemonics are supported.
Awlsim can emulate CPUs with two and four accumulator registers (S7-3xx and S7-4xx).
Compatibility to S7 hardware is taken seriously by the awlsim project. We want to be as close as possible to the real PLC hardware with our AWL/STL code execution. For this reason awlsim ships an extensive selftest suite. Missing features and differences between awlsim and Step 7 are documented in the COMPATIBILITY.txt and TODO.txt files. If you find any undocumented bugs and incompatibilities to a real PLC CPU, please contact us.
Awlsim is Open Source Free Software licensed under the GNU General Public License v2+. That means it’s available in full source code and you are encouraged to improve it and contribute your changes back to the community. Awlsim is free of charge, too.
The official website of awlsim is: http://bues.ch/cms/hacking/awlsim.html