The following information needs to be absorbed before you start; otherwise, you may waste a lot of your time and money...
One Programming Software package does not program any and all programmable logic controllers.
- Each manufacturer of PLCs uses their own unique program development software packages.
- Within each "brand" of PLCs, there is more than one hardware platform and each of those requires a software package unique to that family of processors.
- Some companies will claim that one package programs all controllers of their brand, but in reality, it is more than one package bundled into one opening screen and you still have to open each application separately; it is a marketing gimmick.
- This seeming convolution is unavoidable because PLCs are not replaced everytime something new is introduced, like some do with their cell phones. There are tens of thousands of PLCs that are still running out of our sight that were commissioned over twenty years ago. As chipsets from Intel, etc...are obsoleted, products have to be redesigned with new chip sets. This is a never ending evolution of the installed base.
The Programming Software is NOT the Programmable Logic Controller.
- The PLC executes a downloaded program in machine level language. If you were able to see it, you would see an ocean of bits, 1s and 0s. It is unviewable to all but a select group in the manufacturer's engineering group.
- The software development package allows you to write your program in a symbolic language that is palatable to your brain...that is, logical in its viewability. It is NOT the program that is downloaded into the processor's memory and executed by the controller.
- The program that you write with graphic symbols, such as ladder logic diagrams (LLD), exists only on the screen of your computer. When you save it, it is saved as logical text statements. When you download it...it is compiled/translated into machine language and transferred to the memory in the controller's processor.
If you are going to learn PLC programming, writing programs, reading programs to troubleshoot a process or to make process improvements, you must first learn the primary language, ladder logic diagrams! Other languages such as Structured Text, Function Block Diagrams and Sequential Function Charts must come after you have become proficient with LLDs. There are no shortcuts!
- We have chosen Allen Bradley (Rockwell Automation) hardware/software as our learning platform.
- All PLCs are very similar in their pure hardware state, and ladder logic diagrams between different manufacturers are identical, save graphic differences, and the editor that allows you to configure the logical statements in rungs of symbols.
- You can learn LLDs with almost any controller and supporting software combo. Once learned with one br4and of PLC, the rest come easily if you invested enough time and effort to learn effectively with the first one.
There are three primary families of hardware/software (in order of historical occurrence) with Allen Bradley: PLC5 with RSLogix 5, SLC500 and Micrologix 1000/1100/1200/1400/1500 with RSLogix 500, and ControlLogix/CompactLogix with RSLogix 5000.
- Of these three arenas, the RSLogix500 is the least expensive to use as a learning platform. Within this platform there are three categories of hardware/software:
- The standard license of RSLogix500 will support all SLC500 and Micrologix controllers and it is expensive.
- Micro Starter Lite supports just two controllers; the Micrologix 1000 and the MicroLogix 1100 controllers. The software was free from Rockwell Software but no longer appears on their website. We include it with the manual written using a Micrologix1000 and with any training stations that have a Micrologix1000 controller from our inventory. AB has suspended manufacture of the Micrologix1000 platform since June 2017, but there are millions of them installed in factories and elsewhere and they are still relevant as a learning platform.
- Micro Starter will support all Micrologix controllers and is very reasonably priced. This family of controllers has five hardware platforms and they were introduced in this order: 1000, 1200, 1500, 1100 and then the 1400. The last two, or rather the newest, supports online editing and use of Ethernet communications. The Micrologix 1400 also supports Ethernet/IP. For this reason, our newest lab project manual was developed specifically with the Micrologix 1400.
The Complete PLCLearn Series with the MicroLogix 1000 controller is the absolute least expensive option and is very effective for learning PLCs, programing and ladder logic diagrams. This manual is comprehensive in that it covers all 70 instructions (including some that you will never see or use) supported by the 1761-L10BXB Micrologix 1000 controller.
The Complete PLCLearn Series with the Micrologix 1400 is the best choice even though the software is not free and the hardware is a little more expensive. The real difference in cost is the software, typically $170 from an AB distributor. If you are serious about a career involving PLCs, you are better off going the Micrologix 1400 route and using this manual.