Before modifying your UDT, you can go online, right click on the DB you want to save, and make a caption of the current values. Then you can set the caption as start value of the DB (not sure if I'm clear).

After that when modifying your UDT, your DB will be reinialized to start values, which will be your current values.

Edit: here is a sample of the TIA 11 manual to do this (still works with TIA 13 SP1):

https://support.industry.siemens.com/cs/mdm/57185407?c=28725619595&lc=en-WW

And a Pegaia's post :

https://support.industry.siemens.com/tf/ww/en/posts/tip-step7-v13-sp1-and-the-new-function-snapshot-of-monitoring/120239/?page=0&pageSize=10

Hi,

thanks for your reply!

But if i understand correcly, these start values will be overtaken in the variable each time the PLC goes to Run mode? My variables are retains, but for example i will do the things you described above, do the update and every variable is after a restart exactly as it was before the update. What if they now change a value of a variable from the HMI (recipe etc.) will this changes will be forgotten during a restart of the machine and will that variable again takes his start value??

I know how it works with other brands, but Siemens is still a bit new for me if it comes to this kind of operations....

thanks

Edwin