Declarative vs. Imperative command handling in axis state machines — should mapp Framework be rewritten? Hi everyone, I’d like to open a discussion about two fundamentally different approaches to structuring axis state machines when using MpAxisBasic (or similar function blocks). I’ve seen both pat…

From project owner (a.i.) perspective I can tell you only this. I think both approaches are okay, and it is up to the team of developers which way they would like to go. Mapp Framework is smartly designed, and it shows one way how the solution can look like (imperative way it is easy to use and easy…

Hello, I personaly don’t like doing Approach 2, were cyclicaly Values/Commands are written. This make testing via a Watch Window impossible, it needs cyclic plc performace for the copy action. Considering that i need a Home Command in more than one Step, becuase i need different Home-States for Co…

I agree with Michael for the same reasons. I personally think it’s more readable to handle the state’s actions within the state itself rather than outside of it. However, I think that settings statuses outside of the state machine makes a lot of sense because some statuses may be true in multiple s…

25 years I used imperative approach, because I quess it is easy and eveyrobody understand. But 2 years ago I started use declarative aproach Personal point forced me to change: only one place for change->A lot of customers project, where was a lot of spaghetti code easy to read big projects → no …

I use the approach of setting values exactly then, when I need them. I do not like the other approach, because then if you have to set stuff in multiple places, you’d have MyFub.FirstBool := state = THIS_STATE OR state = THIS_OTHER_STATE OR state = THIS_THIRD_STATE; and I do not like that, at all…

@michael_w I understand the aesthetic objection againts: MyFub.FirstBool := state = THIS_STATE OR state = THIS_OTHER_STATE OR state = THIS_THIRD_STATE; , but this line is actually self-documenting — you can see exactly in which states the command is active in one place. In the imperative approach,…

better is to keep a bug for discussion :grinning_face:

@Vratislav good idea. I’ve reverted my edit so that the rest of the thread makes more sense to anyone who finds it later.

I also prefer the declarative approach and if there is a need for a long OR statement, I break it up to multiple lines. MyFub.FirstBool := state = THIS_STATE OR state = THIS_OTHER_STATE OR state = THIS_THIRD_STATE ... OR state = THIS_N…

I prefer code that is only executed when necessary. I don’t like executing code in every cycle. If I need to know where something is set, I prefer highlighting in the editor and using shortcuts (which B&R doesn’t support as far as I know), like Ctrl+Shift+F in TIA Portal to jump to the next locatio…

Declarative vs. Imperative command handling in axis state machines — should mapp Framework be rewritten?

CoLab Projects mapp Framework [AS4/AS6]

ballazr (Rémi Ballaz) February 20, 2026, 4:45pm 13

Looking forward to how ST-OOP will reshuffle the cards on this topic…

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Declarative vs. Imperative command handling in axis state machines — should mapp Framework be rewritten?

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