oPlc is a powerful program that turns your Mac into a reliable Programmable Logic Controller, supporting Modbus-TCP and Modbus-RTU over TCP for I/O devices. There are more than 80 functional objects available. You can use up to 10 pages, 400 objects and 20 timers. For communication with Modbus-RTU devices an ethernet to RS485 converter is needed.
What’s new in version 1.2
Updated on Sep 21 2012
Version 1.2:
Modbus objects Force Multiple Coils and Preset Multiple Registers added
TCP command listener added (for communication with oWatchdog)