Awlsim - S7 compatible Programmable Logic Controller (PLC/SPS)

Awlsim is a free Step 7 compatible Programmable Logic Controller, that supports the automation languages AWL/STL and FUP/FBD. Awlsim itself is written in Python.

The latest version of Awlsim can be downloaded at the official Awlsim site.

Main git repository

Github / issue tracking / pull requests

Awlsim - Programmable Logic Controller (PLC/SPS)

Awlsim is a free Step 7 compatible Programmable Logic Controller, that supports the automation languages AWL/STL and FUP/FBD. Awlsim itself is written in Python. The speed of execution ranges from several ten thousand AWL/STL instructions per second on slow embedded machines to a couple of million instructions per second on faster computers.

AWL/STL programs on PLCs are used for automation of industrial processes. However Awlsim is very flexible, so it can be used for other purposes beyond industrial applications, too. Awlsim aims to be compatible with the industry standard S7 software on the AWL/STL level.

Awlsim can emulate CPUs with two and four accumulator registers (S7-3xx and S7-4xx). Compatibility to S7 hardware is a task 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 documentation and TODO documentation files.

Quick start tutorial

See the quick start tutorial for a simple example on how to use Awlsim in simulator mode. In simulator mode Awlsim can be run on any desktop PC. No special hardware is required.

Example project

If you don't know where to start, you can find an example project in the examples directory as EXAMPLE.awlpro. You can easily run this example in simulation mode without the need for special hardware.

Git repository

The latest development version of Awlsim can be fetched with git:

<pre> git clone https://git.bues.ch/git/awlsim.git cd awlsim </pre>

After cloning the main repository the git submodules must also be fetched. The following helper script can be used:

<pre> ./maintenance/update-submodules </pre>

Dependencies

Awlsim depends on

Python 3.4 or later (or alternatively Python 2.7)
PyQT 5 or alternatively PySide 2
CFFI

These packages can be installed with pip:

<pre> pip3 install --upgrade PyQt5 pip3 install --upgrade cffi </pre>

If building and using Awlsim with Cython acceleration is desired, Cython must also be installed:

<pre> pip3 install --upgrade Cython </pre>

On Windows all Awlsim dependencies can be installed by double clicking the shipped installer script: maintenance\win-install-dependencies.cmd

For Debian Linux users the script maintenance/deb-dependencies-install.sh installs all required and optional runtime and build dependencies.

Directory structure

The Awlsim Git repository and source archive awlsim-x.yz.tar.bz2 contain lots of files and directories. Here is an overview of the main files and directories and their purpose:

Main executables

User interface executables. The main user executable is awlsim-gui.

<pre> . awlsim-client : Command line client tool. . awlsim-gui : Graphical user interface. This is the main user frontend. . awlsim-linuxcnc-hal : LinuxCNC HAL module executable. . awlsim-proupgrade : Command line tool to update .awlpro file formats. . awlsim-server : Command line server tool. . awlsim-symtab : Command line tool to parse symbol tables (.ASC). . awlsim-test : Command line tool for unit testing. . See tests/run.sh for execution of unit tests. . awlsim-win.cmd : Windows wrapper for awlsim-gui. </pre>

Documentation

These files and directories contain useful information about Awlsim.

<pre> . doc/ : Main documentation. . doc/fup/ : Awlsim FUP language and editor documentation. . examples/ : Various example projects and feature demonstrations. . COMPATIBILITY.md|html : S7 compatibility documentation. . COPYING.txt : Main license. . DEVELOPMENT.md|html : How to enhance and develop Awlsim. . QUICK-START.md|html : Quick start tutorial. . README.md|html : Main README document. . TODO.md|html : TODO list. </pre>

Main modules

The main modules implement most of Awlsim's functionality.

<pre> . awlsim/ : Main Awlsim Python-module directory. This is where the magic happens. . awlsim/awlcompiler : AWL compiler. . awlsim/awloptimizer : AWL optimizer. . awlsim/common : Common libraries, modules and helper functions. . awlsim/core : AWL interpreter core. This is where the AWL program is executed. . awlsim/core/instructions : Implementation of AWL instructions. . awlsim/core/systemblocks : Implementation of SFCs and SFBs. . awlsim/coreclient : Client library to connect to coreserver. . awlsim/coreserver : Server library to provide AWL interpreter core access via networking. . awlsim/fupcompiler : FUP compiler. . awlsim/gui : Graphical user interface implementation (Qt). . awlsim/library : AWL block (FC and FB) libraries. . awlsim/library/iec : Implementation of IEC FCs and FBs. . awlsim_loader/ : Import wrapper for the main Awlsim Python-module. . This is used to automatically load Cython optimized modules. . libs/ : External libraries used for running or testing Awlsim. . progs/ : External programs used in Awlsim. . submodules/ : Git submodules used for running Awlsim. . See man git-submodule for general help about Git submodules. . submodules/pyprofibus/ : PROFIBUS-DP implementation. . tests/ : Unit test cases. . tests/run.sh : Main interface to run unit tests. Please see --help </pre>

Hardware support modules

The hardware modules are the glue between the Awlsim core and the real world. The hardware modules are invoked before and after running the user cycle (OB 1).

<pre> . awlsimhw_debug/ : Hardware module for unit tests. Do not use in production. . awlsimhw_dummy/ : Dummy no-operation hardware module for testing, debugging or simulation. . awlsimhw_linuxcnc/ : LinuxCNC hardware support module. . awlsimhw_pixtend/ : PiXtend hardware support module. . awlsimhw_pyprofibus/ : PROFIBUS-DP hardware support module. . awlsimhw_pyprofibus.conf : Configuration file for awlsimhw_pyprofibus. . awlsimhw_rpigpio/ : Raspberry Pi GPIO hardware support module. </pre>

Misc

<pre> . awlsim-server.service : Systemd unit for awlsim-server. . debian/ : Debian packaging support. . maintenance/ : Maintainer scripts. . misc/ : Miscellaneous scripts and files. . setup.py : Python package build script. This also builds the Cython modules. </pre>

FUP - Funktionsplan - Function block diagram

Awlsim supports programming in an S7-FUP like language. See the FUP documentation for more information about Awlsim's implementation of FUP.

Environment variables

The following environment variables control Awlsim's basic behavior:

AWLSIM_GUI =auto Automatically select the best GUI framework (default) =pyside Use PySide as GUI framework. =pyqt Use PyQt as GUI framework.
AWLSIM_CYTHON =0 Do not attempt to use Cython core (default) =1 Attempt to use Cython core, but fall back to Python =2 Enforce Cython core
AWLSIM_SCHED =default Do not change the scheduling policy. Keep the policy that was assigned to Awlsim by the operating system. (default) =normal Use the normal non-realtime OS scheduling. =fifo Use FIFO realtime scheduling (SCHED_FIFO). =rr Use Round-robin realtime scheduling (SCHED_RR). =deadline Use Deadline realtime scheduling (SCHED_DEADLINE). =realtime Use a realtime scheduling algorithm that performs best in most situations. The actual algorithm selection might change between Awlsim releases. 

The suffix -if-multicore can be appended to the options fifo, rr, deadline and realtime. That will trigger a fall back to normal, if the system is single-core (has only one CPU).
AWLSIM_PRIO =default Do not change the priority (default). =1-99 Set the scheduling priority. The meaning of the priority depends on the operating system and the selected scheduling algorithm. See AWLSIM_SCHED.
AWLSIM_AFFINITY =0,2,... Comma separated list of host CPU cores to run on. Default: all cores.
AWLSIM_MLOCK =0 Do not try to mlockall. See man 2 mlockall. (default). =1 Try to mlockall all current and future memory. See man 2 mlockall. =2 mlockall all current and future memory. Abort on failure. See man 2 mlockall.
AWLSIM_PROFILE =0 Disable profiling (default) =1 Enable core cycle profiling =2 Enable full core profiling (including startup)
AWLSIM_COVERAGE =DATAFILE Enable code coverage tracing.
AWLSIM_GCMODE =realtime Enable manual garbage

Awlsim

Install / Use

README