Logix5000 - Don't write Tag Values?

Still pretty new to the AB world, so here's a clerical question about Logix5000:

Every time I "Download to PLC" it automatically writes my Tag values...
Is there a way to only write the Ladder?
Then have another way to SAVE/UPLOAD TAG VALUES to later DOWNLOAD TAG VALUES?

Reason:
I will have Run Timers for a lot of devices that I don't want to overwrite.
Sometimes setpoints change on site after commissioning, so if I then have to travel to site and update the code (new equipment etc.) it will then take the OLD setpoints from commissioning, rather than during operation.

You can just do online edits to whatever rungs you are changing. As for Your question Ia am not for sure

jtashaffer said:

You can just do online edits to whatever rungs you are changing. As for Your question Ia am not for sure

Click to expand...

Hypothetical (and my case more often than not) the addition we are doing to the system requires a large amount of NEW code to be added.
We will write the code in our office, test it on our "Test PLC", then issue the mechanical/electrical to site, Tradesmen install, then we travel to site and commission.

Now, say I have 5 new rungs in MAIN, and 2 new AOIs w/ their own UDTs.
All of this combined, (I believe) I must rewrite the whole PLC, but I don't want to overwrite the rest of the SetPoints/Tag Data.

devo.xx said:

Still pretty new to the AB world, so here's a clerical question about Logix5000:

Every time I "Download to PLC" it automatically writes my Tag values...
Is there a way to only write the Ladder?
Then have another way to SAVE/UPLOAD TAG VALUES to later DOWNLOAD TAG VALUES?

Reason:
I will have Run Timers for a lot of devices that I don't want to overwrite.
Sometimes setpoints change on site after commissioning, so if I then have to travel to site and update the code (new equipment etc.) it will then take the OLD setpoints from commissioning, rather than during operation.

Click to expand...

You could do a partial download with the PLC-5 without overwriting register data, but I don't think that's possible with ControlLogix. Your best bet is probably to paste in your program changes in online mode.

There is a tag upload/download tool that is an optional install of RSLogix5000. I've never really used it but I believe it's for this purpose. Upload the tag values, download the PLC program, download the original tag values.

This is exactly what the Tag Upload/Download tool is for.

One of my machines has a large set of calibration tables in Array Tags, so on the rare occasions that I have to perform a download, I retrieve the calibration tables with the Tag Upload/Download tool first, then put the values back with the same tool.

It does require a licensed copy of RSLinx Classic; I have that via my Toolkit.

Export and Import Subroutine

You should be able to Export your Routine after changes are made and then import that routine into the plc while online and not effect existing values. I have done so and the only values I see effected is new tags created by the import file. This will also add any UDT,AOI and the Descriptions for any new tags created by the import.
If you use the copy paste method then all new tags and descriptions will have to be entered in the online mode to add to the program file. You can choose this method and import your UDT's and AOI's and this will import Descriptions associated with those items. But, any tag not imported will have to be manually created and described.

Caution! Be sure your Subroutine is identical to existing before making changes and the export file. The import will overwrite the logic of existing subroutine.

Ken Roach said:

This is exactly what the Tag Upload/Download tool is for.

Click to expand...

Alright great!
Thanks a lot guys!

Ken Roach said:

...It does require a licensed copy of RSLinx Classic....

Click to expand...

The cheapest licensed version of RSLinx Classic at our distributor's site is the "Single-Node" version, running in at £350, around $594 !!

Not much of a "tool" then, more a sledgehammer.