mbutils is a library and set of utilities written in FreePascal/Lazarus with intention to provide developers with free and robust tools to communicate with Modbus devices.
- Object oriented design.
- Both, master and slave implementation.
- Easy to extend with new query types.
- Easy to extend with new transport types.
- Absolutely free. No strings attached.
I converted the code to Delphi. It had some bugs in it but nothing major. At some point I kept getting blue screens (SYSTEM_SERVICE_EXCEPION with bugcheck 0x0000003B). It turned out that my trusty USB-->serial converter was misbehaving (Belkin F5U103v). Swapped it for a new one and all was fine! What I like about this library is that in combines Modbus TCP / RTU and ASCII in one library.