Due to the lower cost of hardware and an ever expanding arena of PLC manufacturers, increasing competition among the automation providers is most evident in the number of developers who are providing FREE software for their products. This is in stark contrast to some of the higher end PLC providers who charge $100's and $1,000's for their software packages. Some of these higher-end automation providers do give away their software products - temporarily, but many others give away the full-blown package absolutely FREE. See below for a list of providers with FREE PLC and/or HMI software.
Allen Bradley/Rockwell
Probably the most well known PLC programming software packages available are from Allen Bradley/Rockwell. These packages include the RSLogix 500 and RSLogix 5000 packages. Rockwell software soon became the standard which all other automation providers tried to emulate. Though AB doesn't give away their full blown RSLogix packages, they do provide the RSLogix Micro Starter Lite which is a watered-down version of the RSLogix 500 package, used to program the MicroLogix 1000 and 1100 PLC's. Download the RSLogix Micro Starter Lite for offline programming; however, if you wish to transfer the file to a MicroLogix, you must also download RSLinx, which is the AB communications interface utility. Download the FREE RSLogix Micro Starter Lite HERE:
AutomationDirect.com (Koyo)
AutomationDirect has a few software packages which can be downloaded and utilzied FREE of charge. The most popular software product distributed by AutomationDirect.com is DirectSOFT. A limited version of the DirectSOFT package can be downloaded and utilized indefinately. The limitation on the FREE downloadable version is 100 words; however, this software package is perfect for someone who is just starting out and needs an intuitive tool to learn basic Rung-Ladder-Logic (RLL) programming. Download the FREE version HERE:
Another popular programming product from AutomationDirect.com is the newer CLICK PLC programming software. The dowloadable CLICK PLC software is the full blown version and has no limitations at all. With the downloadable software, you can configure any CLICK PLC to the maximum extent possible. As with the DirectSOFT, the CLICK software is perfect for someone who is looking for a good software package with a lot of special functions. Download the FREE CLICK PLC programming software HERE:
Along with popular PLC programming software, AutomationDirect.com also provides FREE HMI (Human-Machine-Interface) software for the C-More Micro-Graphic line of panels. The C-More Micro-Graphic software offers all of the features users would like to see in premium HMI software: Numerical entry/display, multi-state indicator editors, tag database editor, and an expandable bitmap symbol library. One aspect of this software which really impressed me is that, unlike many other HMI software products, the offline project is a true-to-life representation of what your project will look like in the panel. Download the FREE C-More Micro-Graphic panel softare HERE:
TECO SG2
Although the TECO SG2 series is officially listed as a Programmable-Logic-Relay (PLR), the programming software can be programmed in RLL format as well as function block format. The instruction library includes all the popular items: Timers, counters, enchanced math functions, file functions, and even DRUM sequencers. The SG2 software also includes a built-in simulation, which is as true-to-life as any I've seen. The simulator allows the user to simulate digital inputs, digital outputs, and even the analog inputs. You can easily debug your project before you download it - which can save you time. Download the TECO SG2 software HERE:
Entertron Eware32
Another popular FREE PLC software provider is Entertron Industries Inc. Entertron has been a player in the PLC and PLC programming software arena for over 30 years and were one of the original providers which offered FREE software from the beginning. Entertron's downloadable PLC Relay Ladder Logic Software, Eware32, is the full-blown version which Entertron provides to configure their ePLC's series of PLC's. The software includes all of the functions that one would expect from a long standing PLC provider and is remarkably intuitive. Download the FREE Eware32 Software HERE:
The above list is not all inclusive. There are other free software providers out there, but as mentioned above, most all of the other providers who advertise FREE software have a time limit on the software whereas the user must pay to activate the software within a certain time, usually 30 days (or less).