Renaming tags in TIA portal

[Jim G.]

I have a small modification that I want to make to a program in an S7-1500 using TIA portal V14 SP1.

I have a global data block containing some tags labelled as "Spares". The block contains non-optimized tags.

I want to use some of these spare tags and just rename them for my purpose.
I know how to do that.

What I want to know is upon downloading the changes, do I need to re-initialize the block values? How do I put just tag name changes in without changing or re-initializing any values. The spare tag are only going to br renamed for future purpose.

I hope this inquiry makes sense. I an still learning Siemens and TIA portal.

Thank you

 

[Lare]

You have two ways to do this.


1. take snapshot of current values, make modifications, download changes and load snapshot values back to DB.
(After download values are different (start values) as long as you have restored snapshot, at least I think so.)
https://support.industry.siemens.co...3-sp1-and-restore-them-in-v14-?dti=0&lc=en-GB


2. Another method. Take first snapshot.
- mark variables as setpoints (at least them, which you want to save as initial value)
- mark variables as retains on DB.
- Copy snapshot as start values.

- make modifications to DB, after download you have same values on setpoints as them where on snapshot. (start values after initialization)


Also if CPU is restarted your block remains values or values are start/init values (from snapshot)
https://support.industry.siemens.com/cs/mdm/109011420?c=69540267403&lc=en-WW

 

[mk42]

If you're using optimized blocks, "Download without reinitialization" is the tool for that; the trick is that you need to activate it, download, and reinitialize everything BEFORE you need to use it to add tags on the fly.

https://support.industry.siemens.com/cs/ww/en/view/76278125

Since you aren't using optimized, I'd recommend what Lare said, to utilize snapshots to set the start values appropriately. Should be fine for things like parameters; might be tricky for things that are constantly changing.

 

[L D[AR2P#0.0]]

As an alternative, you could create another global DB and use that for your new variables and hence download without interfering with existing DBs.

 

[Jim G.]

I thought about creating a new global DB and creating the tags there. Will I still be prompted to re-initialize when I download the changes?


Thanks

 

[L D[AR2P#0.0]]

If you haven't modified any existing DBs then no.


You could also 'demo' this by trying it out using plcsim.

 

[mk42]

I thought about creating a new global DB and creating the tags there. Will I still be prompted to re-initialize when I download the changes?


Thanks

You only reinitialize the DBs you change when you download. the existing DBs won't be changed, so they won't be reinitialized.


Whether the new DB is being reinitialized or not (just initialized, since its the first time?) might boil down to sematics, i guess, but you aren't losing data there because it doesn't exist yet.