What are the most important PLC programming skills for a beginner to learn?

There is no question that flow charting helps with understanding and trouble shooting of code of logic. State driven logic similar to PLC Open architecture is more suitable. Years ago while manufacturing engineer at GE Lighting plant, I developed a scheme that uses ladder code to accomplish this better than SFC programming Language since in SFC after the transition state to a divergence if all conditions equal, SFC cannot guarantee which branch will execute first. I have published this Application note on (Intelligent platform site years ago).

1980s KISS principal.(Keep It Stupid Simple) Learn the machine/process, IO, HMI needs. Break it down into small independent functions and data structures as much as possible. Don't overcomplicate things. Use flow charting or psuedo coding to define individual functions and flow/ordering. The complexity and visibility of your code does not matter. Troubleshooting should not be done via code inspection. Diagnostic code should guide troubleshooting. The more time you spend on diagnostics the more uptime for the system. Anyone can hack out a widget maker program, but few can simplify and create great flow and diagnostics. Difference between engineering systems and coding for inspection. If the function works nobody needs to see it!

1. Understanding PLC scan cycle: Learn about the sequence of steps involved in reading inputs, executing the program logic, and updating outputs within a PLC. 2. Memory structure comprehension: Gain knowledge about how data is stored and organized in PLC memory, including bits, words, timers, counters, and registers. 3. Grasping data types: Familiarize yourself with various data formats like boolean, integer, real, and string, which are essential for handling different types of information. 4. Mastering instruction set: Acquire proficiency in executing commands such as logic, arithmetic, comparison, and communication, forming the backbone of PLC programming.

Another important concept is the syntax and parameters for commands. You can understand that COP and CPS are instructions you can use, but knowing exactly how they work is key. Both Siemens and Allen-Bradley use a myriad commands that can sometimes be difficult to divine meaning from. For an Allen-Bradley example, copy or synchronous copy. They perform similar operations and take the same parameters. However, the difference between the two is critical to understand. Make sure you have documentation on hand.

One of the most crucial PLC programming skills for beginners to learn is mastering ladder logic. Ladder logic is a graphical language resembling electrical schematics, making it easy to understand and widely compatible across various PLC brands. To excel in ladder logic, focus on understanding basic symbols like contacts, coils, timers, counters, and functions. This foundational knowledge will pave the way for efficient PLC programming.

For a beginner in PLC programming, mastering ladder logic, understanding basic electrical concepts, and becoming proficient in structured text are crucial skills. Ladder logic forms the foundation of PLC programming and is widely used in industrial settings. Understanding basic electrical concepts helps in comprehending PLC hardware and wiring. Structured text, akin to high-level programming languages, offers more flexibility and efficiency in creating complex algorithms, loops, and functions, making it indispensable for advanced PLC programming tasks.

The thing about structured text that makes it both useful and dangerous, is how much you can simplify operations. You can use an IF-statement to assign a true/false value to a variable (let's say MOTOR-ON), or you can assign the output of your IF-logic to the variable. You can reduce the code size cleverly but you risk making your logic obscure. It is a delicate balancing act. However, the flexibility is worth it.

An essential debugging tool to be aware of is Cross References. A Cross Reference indicates where a variable is accessed (Read/Written) in the program. In Ladder Logic, for example, it may be used to identify where a Coil's associated variable is Set/Reset. Emerson's PAC Machine Edition simplifies this task by using the References tab in the Feedback Zone, providing easy navigation to the references using function keys.

One crucial skill for beginners in PLC programming is mastering debugging tools. These tools, like breakpoints and watch windows, are your allies in identifying and fixing errors efficiently. They allow you to pause execution, monitor variable values, and manually override inputs or outputs. With trace functions, you can track variable changes over time, enabling smoother debugging processes. Becoming proficient in these tools will empower you to troubleshoot effectively and ensure your PLC programs run smoothly.

In PLC programming, a beginner should focus on mastering ladder logic and understanding its real-world applications, while also delving into data types, variables, and memory management to ensure efficient programming and troubleshooting.

Sharing information on your projects and work is tricky for programmers. You need to manage expectations while keeping your stakeholders informed. When I make changes I use two channels of communication. One with my technical team members who need to know exactly what is going on. The other with stakeholders who use the system such as an operations or maintenance team. I'll also send detailed documentation in the form of an email to my stakeholders, in addition to talking in person. This also opens communications about issues or improvements to the system from the stakeholders point-of-view.