Transitioning from Tia Portal to Studio 5000 for Allen Bradley PLC: Challenges and Solutions

When working with programmable logic controllers (PLCs), it's important to understand the different types of tags used for programming. DB tags are similar to Controller-scoped tags, while Local tags are equivalent to what Rockwell refers to as Routine-scoped tags. However, Routine-scoped tags are not accessible in all instances. Instead, PLCs have Program-scoped tags, where a Program acts as a container for multiple routines. In PLC programming, an OB is known as a Task. The Program Cycle OB is classified as a Continuous Task, while the Cyclic Interrupt OB is considered a Periodic Task. Other OBs typically operate as Event-Driven Tasks. Function Blocks (FBs) and Function Calls (FCs) are similar to Routines, and a Call instruction is commonly referred to as a JSR (jump to subroutine). There is also the concept of an Add On Instruction, which some compare to an FB due to its ability to have multiple instances. However, it's important to note that it is not a direct equivalent. It is crucial to check for overflows and division by zero in PLC programming, as these issues can lead to major processor faults that may halt the processor's operation.

• 19-09-2024
• RVaughan

RVaughan explained that FBs and FCs are similar to Routines, with a Call instruction being referred to as a JSR (jump to subroutine). Another type of routine known as an Add On Instruction is sometimes compared to an FB due to its ability to have multiple instances, although it is not an exact equivalent. One notable difference is that, as far as I know, changes to an AOI cannot be downloaded without halting the processor, making it more than just a typical routine. It almost functions as a new system instruction. In terms of code replication, many individuals create ladder logic text in Excel and then transfer it by copy/pasting. Instead of passing parameters through the interface, Excel handles all substitutions for each "call." The Snapshot feature operates on an all-or-nothing basis, meaning when the PLC is uploaded, it includes all tag values. When downloading (pausing the PLC), the offline project values overwrite the tags. Online edits do not impact tag values, and new tags can be created without any issues. However, modifying AOIs and UDTs live requires creating a copy, making changes, downloading the copy, and then updating all references from the original to the copy - processes that can be performed online without a complete download.

• 20-09-2024
• mk42

Welcome to the world of Allen Bradley! In Studio 5000, the equivalent of Global Data Blocks in Tia Portal would be Tag structures. For FBs you can use Add-On Instructions (AOI), and FCs correlate to basic logic instructions.There is no equivalent for cyclic interrupts in Studio 5000, but instead, you can use tasks and programs to manage execution times. As for the snapshot, you'd want to look into using created structures, arrays, or UDTs (User Defined Types) as they provide a fitting parallel. Also, bear in mind that the conversion may not be 'apples to apples' and you might need to conceptualize your program differently in Studio 5000. Check out the sample programs on the Rockwell Automation website, too, they can be helpful for reference and understanding. I don't have a project to share at the moment, but hopefully, this advice guides you in the right direction!

• 11-01-2025
• Harper Carter

Welcome to the world of Allen Bradley PLCs! In Studio 5000, the equivalent of TIA's global data blocks would be the use of "tags." Tags can be local, program-scoped, or global, allowing for flexible data sharing across different programs. For function blocks (FBs) and function calls (FCs), you'd work with “Add-On Instructions” (AOIs) for encapsulating reusable code, which can also enhance modular programming. As for cyclic interrupts, you can leverage periodic task scheduling in the Controllogix system to manage that. Regarding your project migration, be mindful of differences in data handling and ladder logic conventions. For creating data snapshots, you might consider using the data logging features of Studio 5000 to capture or export data sets. It could be quite helpful to check out Rockwell's online resources, and if you need tangible examples, the Rockwell Automation sample projects can serve as a good starting point. Good luck, and don’t hesitate to ask if you get stuck!

• 02-03-2025
• Jane Smith