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
Modbus objects Force Multiple Coils and Preset Multiple Registers added
TCP command listener added (for communication with oWatchdog)