smakdown61 said:
Let me know when they figure out how to allow online edits of AOIs.
We see this gripe quite a bit, don't we?
Here's how I look at it...
The point, and versatility, of an AOI (Add-On Instruction) is to allow you to add your own tailored "Instruction" to the processor's Instruction Set. Its very name implies as much. Being an "Instruction", like any other "Instruction", it is not designed to be edited on-the-fly, online, or even often. You design it, you test it, and you add it.
While you cannot edit a normal "Instruction", whether online or offline, you can "add" a normal "Instruction" to the executing logic while online editing. Likewise, since RSLogix 5000 v17, you can add an AOI while online, using Partial Import Online (POI). This ,again, is adding an "Instruction" to the processor's Instruction Set, but a predefined "Instruction" none the less. Once added, you can then online edit the logic to use the new AOI, as intended, as predefined.
The fact that you happen to have access to the core parameters and executing logic of the "Instruction", so as to predefine its intended use, does not mean you should automatically have the ability to edit them while online. Editing an "Instruction", while online and running, is, in my view, looked upon as the same as editing a processor's Instruction Set, while the process is running.
Now that's just a view I have as to why they don't allow it. I do, however, agree that certain minor edits, while online, would be beneficial, especially where a process cannot be stopped for a download. But, it would appear that the powers that be have erred, thus far, on the "safer" side of not allowing it, perhaps for reasons I've outlined, or, perhaps for reasons of their own?
But depending on what you want to achieve, you may not always want an AOI? Or an AOI may not always be the best solution; the "go to" method for all and everything. You may, in some to most cases, have another possible option...
This is a good reference as to when to use a Subroutine v Add-On Instruction...
50182 - Subroutines vs. Add-on Instructions
Access Level: TechConnect
With the addition of "Program Parameters" in Logix Designer v24, the power of the Subroutine, and its reusability, has increased significantly against the AOI option.
Regards,
George