Sign in to follow this  
Followers 0
chantecler

Can I download a program without overwriting data values?

6 posts in this topic

Hi guys,

Is there any way to preserve the current value of a variable present in the PLC when I download a program with RSLogix 500?. I mean that I want to download a modified program without overwrite some data.

In this particular case I am doing some improvements to a program and when I download it I do not want the machine production counter to be modified.

Thank you
 

Share this post


Link to post
Share on other sites

The Rockwell Automation PLC platforms have never supported that sort of functionality.  I's something that Siemens is very proud of, but of course you need to very carefully designate and monitor that data area.

A popular workaround is to use a Rockwell utility to upload specific data registers, then perform your program download, then restore the values of those registers.

There's one called the "Data Preserve Download Tool" that's for ControlLogix family controllers (v13 and up), and another general purpose data upload/download tool called the "Tag Upload Download Tool" that works with MicroLogix, and PLC/SLC controllers.

 

https://rockwellautomation.custhelp.com/app/answers/detail/a_id/32503/page/1

 

The Tag Upload/Download Tool does use the OPC Automation Interface, so you need an OPC-capable license (anything but Lite) for RSLinx Classic to use it.

Share this post


Link to post
Share on other sites

Note that the Siemens data preservation only works until you have to change an FB in such a way that you have to recompile its DB (changing the interface area of the FB will do the trick) or add/remove/change a DB. If you download the DB, you will overwrite the online data. There is a way to save the online data but it's a little roundabout and troublesome.

 

That's based on my experience with Simatic Manager. TIA Portal may change things.

Share this post


Link to post
Share on other sites

If keeping existing data, values, parameters, text strings is important, I personally, tend to have two copies open.  The first is the current and online program, while the other is the offline version with the changes.  I then copy and paste from offline into the online.  Granted, there are certain versions of MicroLogix that only allow offline programming and forcing of a full download.  In that case you have to use the "Tag Upload Download Tool".  Then again, I would never buy and use those versions of MicroLogix.  I would always buy at least a ML1100.  I would never torture my customers by giving them something that they couldn't really working on.

Share this post


Link to post
Share on other sites

The use of copy/paste works with the data files. If you already have the changes in an offline file then open both the offline and the online in two instances of RSLogix. Right click on a data file in the online file and 'copy'. Then go to the same data file in the changed offline file, right click and 'paste'. Continue with other data files as needed.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0