DB as UDT type

How can I update an DB created as UDT type. I mean I have UDT1 and then I created a DB1 as UDT1 type. Then I changes UDT1, so the data in DB1 are not valid any more. What should I do to update them, and not to create once again the same DB1?

Open the DB in declaration view, then use "File>Check and Update Accesses" which will resolve the out of date interface for the UDT. Now save the DB.

As with most Siemens software, there is another way. With the DB open in declaration view, right click on the line defining the structure which is also the line just above the one with the * on it. Select "Update Declarations" from the pop up menu. When it is done, save the DB.

Hi, the problem is that when I declare DB as UDT type there is no option "File>Check and Update Accesses", that is why I posted my post.

Re-create the DB or ....

You can delete the DB re-create it call UDT as reference and download to PLC,

If you dont want to lose the data and be able to restore values go online copy the DB to a Folder in your project.

THe update acceses is where there is a call to that DB, and after the change it is highlited in your code as red. You would have to update acceses in all of the functions where there is a link to the DB.

Regards

Rheinhardt

I see what you mean if you create a DB and create it as "DB of type" and then "UDT1" in your example. I do not know how to update this DB.

However, when I create a DB to reference a UDT, I create the DB as type "Shared DB". At this point, there is no relationship to the UDT. I then open the shared DB. I give it a symbolic name in the name column, then in the type column I type in the UDT name ("UDT1" in your case), and finally, clear/delete the value in the initial value column.

If you change from Declaration View to Data View (View -> Data View), you can see all the components of the UDT.

Now, if you change your UDT, you can update the DB using either the method Simon or I suggested in the previous posts. You will not need to delete the DB and recreate it.

Now I could not find anything on DB of type UDT. What is this used for that is different than the shared or instance DBs? Am I missing out on something?

A DB created of type UDT is similar to an instance DB. If you change the interface of an FB, the instance DB becomes useless and it must be re-created if you want to view it with parameter names. If you change the UDT interface, the DB has to be re-created.