Siemens TIA data blocks

Hi everyone,

I am normally not in Siemens PLCs, so I have a relatively beginner question.

In a data block (DB3), I added a few rows to it. When I go to load it to the running PLC, I get "Data block re-initialization, The data blocks will be re-initialized with their start values."

The question that I have will this initialized all of the data blocks (there are 20+) or will it just initialized just DB3?

Tnorman said:

Hi everyone,

I am normally not in Siemens PLCs, so I have a relatively beginner question.

In a data block (DB3), I added a few rows to it. When I go to load it to the running PLC, I get "Data block re-initialization, The data blocks will be re-initialized with their start values."

The question that I have will this initialized all of the data blocks (there are 20+) or will it just initialized just DB3?

Click to expand...

Would it be difficult to make a test to see which it is?

It will only initialize the block being worked on or modified.

When it says "data blocks will be re-initialized.." it is just a standard text to cover the case when there is more than 1 DB.

Probably should of posted this picture before hand. I am no talking about the selection under "software". I am talking about the Data Block section.

Tnorman said:

Probably should of posted this picture before hand. I am no talking about the selection under "software". I am talking about the Data Block section.

Click to expand...

It only does it for the DBs listed in the "overwrite" section underneath Software. Only the things you're changing get reinitialized.


If you're worried about this, you can use a feature called "download without reinitialization" that allows you to do exactly what it says, add tags to a DB without resetting the rest of it. Essentially, activating the feature predownloads some spares. You can then add tags to a DB and DL without reinitializing. Downside is A) you need to activate the feature and DL BEFORE you want to use it. B) you can't edit the existing parts of the the DB once it's active C) once you fill the predefined extra space, you need to do a full DL with reinitialization to get the spare space back.


It's a bit of a pain while you're still commissioning, but can be really really handy in production.

You could always create a new DB with the extra data you require.

Thanks everyone! With how late in the afternoon it is, I decided to wait for Monday to apply the changes. I really don't want to screw something else up, on a machine that is running over the weekend.

You could take a snapshot before editing the DB and send the snapshot back down after downloading. This should work for any tags in that DB that were not changed.