oPlc is a powerful program that turns your Mac into a reliable Programmable Logic Controller.
There are more than 80 functional objects available.

● thousands of universal Modbus Input and Output devices available to connect via IP...
● use oPlc at home to control electric, heating, ventilation, cooling, access security, etc...
● control your model train track or other hobby equipment...
● use oPlc for education; learn the basic functions of a logic controller...
● contains basic HVAC components...
● use oPlc on a dedicated Mac mini for professional purposes...

There are many different objects divided into the following groups:

● Common - marker, register, timer, counter, time schedule, setpoint
● I/O - ModBus read or write coil, input and holding register
● Logic - digital port (N)AND, (N)OR, EXOR, flipflop, switch, BCD converter
● Compare - greater-, equal-, less, high and low limiter
● Calculate - add, subtract, divide, multiply, data conversion
● Controller - on/off, off/on, segmentation, PWM, P-regulator

For communication with Modbus-RTU devices an ethernet to RS485 converter is needed.

What’s New

Version 1.3

If you have a problem using oPlc, please don't write a review, but send us an e-mail so we can help you!
● New object TREND for data logging.
● New objects for converting IEEE 754 single precision (32 bits) to/from integer (16 bits) used by Modbus.
● Listener for oWatchdog improved for OS X 10.11 or higher.
● Bug fixes and some improvements.

Ratings and Reviews

2.0 out of 5
1 Rating

1 Rating

Kirkkerekes ,

Too buggy to bother with.

This app is basically abandoned and bug-riddled.

Just for example, the 2012-added “Force Multiple Coils” appears to have no function, as there appears to be no way to get multiple values into it, and single values generate a runtime error “ a little "red 1→?” that is undocumented.

Additionally, the overall execution speed is very slow, and the app regularly loses track of what is going on — errors persist about objects that have been deleted from the workspace.

The developer needs to at least test every function before calling the app done.


Opticom Engineering B.V.
5.1 MB

OS X 10.7 or later, 64-bit processor



Age Rating


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.