MICROBLX: real-time, embedded, reflective function blocks

What is it?

Microblx is an lightweight, dynamic, reflective, hard real-time safe function block framework:

• Pure C, no external dependencies
• Lua scripting for system configuration and deployment
• Standard block and type library
• Webinterface function block to introspect and control blocks
• Automatic block stub code generation
• Generic Lua scriptable function block
• Dynamic type handling, no code-generation
• Similar to IEC-61508 and IEC-61499 functions blocks

Dependencies

• luajit, libluajit-5.1-dev (>=2.0.0-beta11, for scripting (optional, but recommended)
• clang++ (only necessary for compiling C++ blocks)
• gcc (v4.6 or newer) or clang
• only for development: cproto to generate C prototype header file

Building and setting up

Building

$ Just run "make".

Some blocks have external dependencies and may fail. Check for a README in the respective subdirectory.

Note: currently blocks are not installed yet, but instead used from the location where they are built. This will change soon.

Source the env.sh script to setup Lua module paths

$ . env.sh

That's it.

Documentation

• Quickstart
• User manual
• API Changes

Community

Feel free to ask questions on the microblx mailing list:

http://lists.mech.kuleuven.be/mailman/listinfo/microblx

FAQ

I get module XZY not found

Did you source the env.sh script or setup your environment otherwise?

My script immedately crashes/finishes

This can have several reasons:

• You forgot the -i option to luajit: in that case the script is executed and once completed will immedately exit. The system will be shut down / cleaned up rather rougly.

• You ran the wrong Lua executable (e.g. a standard Lua instead of luajit).

Real-time priorities

To run with real-time priorities, give the luajit binary cap_sys_nice capabilities, e.g:

$ sudo setcap cap_sys_nice+ep /usr/local/bin/luajit-2.0.2

License

See COPYING. The license is GPLv2 with a linking exception. It boils down to the following. Use microblx as you wish in free and proprietary applications. You can distribute binary function blocks modules. Only if you make changes to the core (the microblx library), and distribute these, then you are required to release these under the conditions of the GPL.

Acknowledgement

Microblx is considerably inspired by the OROCOS Real-Time Toolkit. Other influences are the IEC standards covering function block IEC-61131 and IEC-61499.

This work was supported by the European FP7 projects RoboHow (FP7-ICT-288533), BRICS (FP7- ICT-231940), Rosetta (FP7-ICT-230902), Pick-n-Pack (FP7-NMP-311987) and SHERPA (FP7-ICT-600958).