Compile GT Designer 3

Is there any button for compiling/Rebuild all in GT Designer 3?
Looked around for a while now but cant find it....

No, I think it does some sort of compile when you download it, in general I think is run in some sort of interpreter rather than an exe. It appears it is probably encoded into some form of binary code when downloading.

Must be something like you proposed. I just wanted to catch errors from my fidling, change project that syncs GT Designer with GX Works 3. Everything seems to be symbolic now. Ahh well, will find out soon enough.

The only thing you can do is validate the project , put any C type script in a C compiler to check syntax, be aware of symbolic only addressing, does not work on older processors, never tried it on later ones so have no experience, on older processors (GXWorks2) symbolic only cannot be read by the HMI, symbolic tags are allocated at compile time so are actually real tags in an area reserved for the compiler. I think downloading the symbolic (tags) is only availlable in IQ series.

Just start simulation, both in Gt Designer3 and GxWorks3, it works very well. You will be able se in GxWorks3 changes when you input values in Gt Designer Simulator.

As Goghie says, you can also simulate on the PC with a real PLC i.e. use GXSimulator as the HMI.