RSLogix 5000 Download Query

Hi,
I have a task to modify an existing Allen Bradley ControlLogix PLC program. I have modified 2 tasks only slightly in the entire program. What I would like to know is how the Download function of RSLogix 5000 works. e.g When I download my modified version of the program will only the differences be downloaded or does the entire program get downloaded with tags etc. What I want to avoid is overwriting any tag values that have been changed on the HMI (set points etc). In the past I have used Siemens S7 & would simply have downloaded only the blocks I had modified, but I am not sure if this can be done in RSLogix 5000.

Any help appreciated.
Thanks
Paul.

In general, a download will download everything. There are ways to retain existing data, but I don't always trust them.

If your version supports it, the best way to download logic portions only, is to export the rungs/routines in the modified program, and then import them online with the replace option. That will create needed tags, but leave others unchanged.

You can also just open a copy of each (online and offline), and then copy and paste the logic.

rdrast,
Thanks for the reply. What are the 'untrusted' ways to retain data?

Thanks
Paul.

Yes, I am interested in these ways to

dr_cronik,
My plan was to do the following:

1) Export all routines that have changed.
2) Go Online with original program & upload to save tag data to PC
3) Delete offline routines that have changed & import with modified ones.
4) Go Online & Download to controller.

Think this should work.
Paul.

Hi Paul

Yes this does seem possible, not sure if step 1 would be required.

I shall give it a try on my test rigg and report my findings

Regards

When you install RSLogix there is a separate tool you can install called the "RSLogix5000 Data Preserved Download Tool". This allows you to download a program and choose which data values should be used, the ones in your offline file or the ones currently in your PLC.

It's a little quirky. You have to open your program and set your project path to the PLC before launching the tool. It's too bad this couldn't have been integrated directly into Logix5k.

dmroeder,
Thanks for the information. I will give the Data Preserved Download Tool a try.

Thanks
Paul.

you say you have only "slightly modified" 2 tasks.

Could you not repeat these mods as "online edits" ?

You can do all the mods you require while the machine or process is running normally, then, at the press of a button, enable new code/disable old code (Test Edits). You can immediately return to the original code if it goes pear-shaped (Untest Edits), repair what you need to, then Test Edits again. Repeat the process until the program runs as you want it to, then Assemble all the edits.

daba,
Thanks for the tip. The slight changes are to an add on instruction (adding of more parameters) that is used about 12 times throughout the program.

Thanks
Paul.