Changing Alias Tags for an Online Controller

Dryhops

Member
Join Date
Jan 2018
Location
California
Posts
90
I am working on expanding a control system for tanks, adding two additional ones.

Each tank is represented by it's own equipment phase. The equipment phase logic is generic, and common to all tanks - all of the phase tags are alias tags. For instance, for the 7th tank, some phase tags look like the following:

attachment.php


Basically, I have copied the generic equipment phase for a new tank, and I now want to edit the alias phase tags to point to the the proper new tags (using the above example, I want to change ProgramControl from Program_Control[7][C] to Program_Control[8][C]). Easy enough normally, but I need to do this online. It is not possible to directly change an alias tag while online.

So I have couple questions related to this problem:
1. Can I make a new tag, say Program_Control_TEMP that aliases Program_Control[8][C], then delete the OLD Program_Control and then finally rename my temp tag back to Program_Control?

2. These phases are currently unscheduled, so the logic won't run. Assuming I can do that temporary tag dance, will deleting a phase tag used in the logic fault the online controller, or have any other implications?

3. If I am able to do everything in my prior questions, and I get my phase alias-ing all of the correct tags, can I then schedule the phases while still online?


Thanks in advance for any help!

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HA HA HA!!!

That's a GEA Program, taking a guess 21st? If so, I did your Ignition system. I no longer work for GEA but am in Systems Integration so my services are available :)

I was their resident expert on their PLC program standard (less you talk to Ireland).

What you wanted to do, may not work properly because the tags might be "on scan" to the SCADA system so you might not be able to delete the tag. HOWEVER, you probably can RENAME it. So create the new tag as ProgramControlNew, rename the original to ProgramControlOld, then rename ProgramControlNew to ProgramControl.

Good stuff!
 
You won't have any issue of faulting the controller. If you are adding additional phases though, you might get into some issues with the Entity handling, but if I recall, I made it so you shouldn't have to worry about it however you'll have to configure the details for it to work right. I did most of the Cellar programming (maybe half actually...?), the fermenters are simple so you'll probably be able to figure it out.

PM me if you want my new contact info.
 
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Nothing like having the original programmer to answer your questions! I've seen some posts by you on the inductive automation forum and always wondered if it was the same GEA code. I'll definitely be in touch as this project moves forward. These tanks are going in the existing cellar, but we are also added a new cellar and controller in the near future.

For what it's worth, the system has served us well since commissioning and I appreciate the modular nature of the project. It seems mostly trivial to expand it, other than trying to do so while the controller is online.

I've gone through every rung a few times and believe I have a good understanding of the entity handling. Obviously you're a few years removed, but this is what I've done so far - am I missing anything major?:
-Added AI and valve AOI, also set up the new tank level calculation AOI
-Put each valve device number into the Ent_Valve_Assign array (determines if a valve is part of the entity)
-Updated the pointer for each new entity to reference the starting index in Ent_Valve_Assign
-Updated the Entity_Phase array, to associate the phase number with the entity number (In this case there's only one entity, the tank, in the phase)

Taking the cellar PLC out of run puts all of the running program phases into idle, so I'm doing my best to avoid a disruption. I will try the tag dance today and report my results.
 
Glad its served you well, i am pretty proud of that one. Of course knowing what i know now i would have done some things different but thats how software development is. There are some Ignition optimizations you could do, if you ever want to formally discuss it.

You have a good understanding of the entity setup, might be some additional configuration for the program control to array to accommodate it as well, memory is a bit hazy. Hopefully you got an excel file that had all the device and entity configurations at hand off? Easier to configure entities with that as it has scripting to update the plc array references.

That project is why I have the job I have now, i will send you a PM with my info. I am at TechED in san diego, any chance you are down here?
 

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