Hi.

( TIA Portal v 18 with S71200 & MTP1200 )

I have a string var located in a PLC DB.

This variable is conected to HMI tag (1s).

And displayed into IO_Field

In HMI screen I can see the correct value ( no user logged )

When I press on another control with user rights needed. The login screen appears and I login the user.

And then .... I can see "0" on the IO Field. ¿ Why ?

The value on PLC DB is the same as previous, and correct.

If I change the value ( Online connection to PLC ), then the new one is displayed.

Thanks !

Hi,

As described in chapter 3.2 of the FAQ "Login and logout behavior with WinCC Unified PC Runtime", there is an error in V18 which causes a language change after a user change. This should explain the behaviour. Maybe setting the output format to {S} will also help, but I'm afraid it won't.

Kind regards
Stefan

Hi

{S} not helps.

I have also encountered the same problem when changing the language.

Why when I change language the displayed value is 0? Shouldn't it show the value of the PLC variable regardless of the language?

In this situation, the PLC variable has a value, and another (0) is displayed on the screen.

Before:

After language change:

( Same PLC value)

It only happens with an "IO field" ( mode = output ), If I use "Text box" works fine.

( After a language change: Up: Text box, Down: Io Field, same variable  )

Thanks!

Hi,

As far as I know, this behavior is due to an unhandled language switching function for some types of process values such as string and bool. Unfortunately, when this unwanted behavior was reported to the development team, Update 1 was almost complete, so they were unable to fix it in Update 1.

Until Update 2 is released, a scripting workaround is required. Reloading the screen should also result in the correct values being displayed.

Kind regards
Stefan