[Logix] What's the best way to update tag values when you have programming changes?

I'm trying to figure out the best way to make sure I don't lose data when I make a programming change to my ControlLogix and CompactLogix PLCs. I'm not sure how to succinctly describe what I'm dealing with, so here's a run down of what I'm seeing:

1. PLC is running, and is incrementing counters for things like runtimes, number of starts, etc.
2. If I'm offline and two hundred miles away from the PLC, it continues to run while my last save in the development software has old values for counters, operation setpoints, etc.
3. If I make a code change offline, I can't go online with the PLC until I update the code.
4. Therefore, it seems impossible for me to make code changes here in the office and then upload them later, if I don't want to revert back to the old saved values for counters, setpoints, etc.
5. Even if I go online and save data on site, the time between my last save and when I upload code (if the plant continues to run) presents the same challenge.

Am I missing something here? Is there a better way of doing this? I have a hard time believing that there is no way to make offline code changes and then upload those changes without having to go through all these counters and manually update values and etc. But heck, maybe that's just how it goes. It would just be nice to do some mundane code changes here and upload it without destroying all the data. How do you guys deal with things like this?

Copy & paste edited rungs from an offline program to the online program AND AT THE SAME TIME BEORE ACCEPTING EDITS delete the original unmodified online rungs.

Of course, this could get really convoluted with large changes. If so, then copy all your new rungs in but disable them with a single bit. Use that same bit to enable the original. This gives you ability to quickly go revert back and forth as needed.

To AGill's point, I pretty much do my offline changes and make sure it works then copy it all in when onsite. I'll go online and in one single action delete all the rungs in a routine, paste all the rungs of my offline program at the bottom, then accept the changes. This way I don't waste time tracking rung that I changed. I do make sure that what I am working on isn't process critical at the moment I make a change

If it's all new code, then I usually just export/import as a .L5X file.

Rockwell has a utility that you can select to install when installing Logix/Studiok5 called something like the "tag preservation download tool" that will allow you to download logic changes, but keep the original tag values in tact.

dmroeder said:

Rockwell has a utility that you can select to install when installing Logix/Studiok5 called something like the "tag preservation download tool" that will allow you to download logic changes, but keep the original tag values in tact.

Click to expand...

I will look into this, thanks!

localize your data and don't reset %MW on cold start in the M340.
hmm, I'll have to learn how to do this w/ the codesissy

dmroeder said:

Rockwell has a utility that you can select to install when installing Logix/Studiok5 called something like the "tag preservation download tool" that will allow you to download logic changes, but keep the original tag values in tact.

Click to expand...

I've post this and similar on the subject before...

Geospark said:

If you are working with systems where it is critical to preserve the current tag data to within a relatively short period of performing a download then you should use the Data Preserve Download Tool. It saves the tag data out to a CSV file and once the project download is complete it then downloads the tag data back into the controller. You use this tool while performing a download so the tag data is as current as possible...

54946 - RSLogix 5000 Data Preserve Download Tool
Access Level: Everyone

Click to expand...

This tool is used with the controller in Program Mode and it must perform a Download. So it is not suitable if you must keep the system running while trying to apply your changes.

But, from some of your points above, it sounds like it would normally be your intention to Download your changes to the controller. That is Download, not Upload. From your points, numbered 4 and 5, and in your closing paragraph, you appear to be referring to Uploading your changes to the controller. Just so you are aware, you Upload from the controller to your workstation and you Download from your workstation to the controller.

So this tool may be of use to you in preserving tag data through a system stoppage and Download of your edited project.

Another available tool, that is often touted here, is the Tag Upload/Download Tool. However, this tool serves a slightly different purpose. It facilitates the Upload of the current tag data in a controller to your workstation, while the controller remains in Run Mode. This is achieved by means of a licensed RSLinx Classic OPC topic linked to the controller. This allows you to save or backup current tag values, such as recipes, PID, etc., and restore them at a later date, also while the controller remains in Run Mode. This tool does not perform a Download. It is only intended as a backup and restore tool. However, it can be used in a similar, but manual, fashion to the Data Preserve Download Tool. You are preserving the tag data in a different manner, via OPC, but must still perform a Download before restoring the tag database, again using OPC.

While the Tag Upload/Download Tool is somewhat more convoluted to setup, and it requires a licensed Edition of RSLinx Classic, it does have its advantages. Besides the ability to save and restore tag data while the controller is in Run Mode, it also allows you to select which tag or tags you wish to include. The Data Preserve Download Tool preserves all tags and is not user configurable.

So again, the Tag Upload/Download Tool is not suitable if you must keep the system running while trying to apply your changes.

The only way to apply certain changes to a controller in Run Mode is to use the available tool - Online Editing. When you have an offline project, that has offline edits that are not yet in the controller, you must transfer the edits from the offline project to the online project using methods already outlined. Copy/paste, drag & drop, routine import, AOI & UDT PIO, etc.

For I/O Configuration changes, AOI or UDT edits, Produce/Consume, etc., you must Download your edits.

Regards,
George

AGill said:

Copy & paste edited rungs from an offline program to the online program AND AT THE SAME TIME BEORE ACCEPTING EDITS delete the original unmodified online rungs.

Of course, this could get really convoluted with large changes. If so, then copy all your new rungs in but disable them with a single bit. Use that same bit to enable the original. This gives you ability to quickly go revert back and forth as needed.

Click to expand...

+1

Make a good backup before starting edits but this is the preferred way in a running system. Yeah, it takes longer due to installing all of the"edit enable" contacts before debug but it's the safest if trouble arises.