TIA portal - synchronize datablock on download

Hi,

Whenever I update a projects CPU with new code and add more variables to datablocks I encounter a problem that I'm sure there is a correct way of solving.

In my project that I'm updating the values of the datablocks are old and when I'll download the project on site I can't figure out how to just download the project without reinitialize the datablocks to the start values and hence loosing all settings etc. I can't make a snapshot since the datablocks will be diffrent and can't go online. What is the best way to solve this?

/Tim

Assuming 1500s:
There is a feature called "Download without re-initialization" where the compiler essentially builds in a configurable amount of spare space into the DB, that you can add tags into without overwriting the rest. This setting is activated individually for each DB.



The big downsides are 1) once you activate this feature for a DB, then the existing tags cannot be renamed or changed types 2) you need to activate the feature (which requires re-initializing the DB) before you can use it.


Essentially, once the machine is commissioned and in a steady state, one of the last steps would be to activate the feature for any DBs you expect to change modify down the road, or at least ones where the start value might change later and be important.


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

Thanks! I have two dbs, one for "status" and one for "hmisettings" so these will be enough. Very good to know! Also seem to work for s7-1200
/Tim

It seems that if the DB is to big with alot of retentive values then I can't download without re-initialization. I have one hmiSetting datablock and this is large and almost everything is retentive. The block can have maximum of 100bytes it seems. Is it a bad idea to have to large DBs? Now I have this DB and alot of struct in it to get it sorted.

not sure for the 1500 but for the 1200, you have the possibility to update each db initially saved value with the actual online value. you use the small icones on the DB page and then, if you download the DB again, it will initialize with those last saved values....You need to do this for each db individually.
first click on the glasses to see live values
then there is a camera icone to save a snap shot of the values
finaly clic the kind of old hard drive icone that say something like copy snapshot to start values...

1500's offer the same functionality as described by Jeff.
Take a snapshot and replace initial values with online values.
Upon download, the initial values will be set to copied/current system, DB values.

rQx said:

It seems that if the DB is to big with alot of retentive values then I can't download without re-initialization. I have one hmiSetting datablock and this is large and almost everything is retentive. The block can have maximum of 100bytes it seems. Is it a bad idea to have to large DBs? Now I have this DB and alot of struct in it to get it sorted.

Click to expand...

You can change how much buffer is stored (and choose separate values for retentive vs non-retentive) in the block properties. The Portal defaults to 100 bytes, though.

If I have modified a datablock, then I can't go online and make a snapshot upon download. I can take them vefore but meanwhile I edit the program , the values in the datablock can change.

Ah, I thought that 100bytes was maximum. I'll try to add more thanks