isde

Hi,

I have created a function block to be able to set and read time. My problem is that I get some problem in the reading part. What's going wrong is that the function doesn't write to the output (and thus the folowing DB). After some testing I have found out that changing from address register AR2 to AR1 solves the problem. However I can't understand why. From the begining I was using AR1 in the first part of the program (set time) and therefore I decided to change for AR2 in the later part. Some of these concepts are new to me so right now I'm trying to get the full picture of how it work.

Adding a picture of the function block.

Very grateful for help and tips!

Best regards isde

Differences between Function Block (FB) and Function (FC)

Dec

One other advantage of FB over FC (from STEP7 programming perspective) is passing the parameters in/out to the function. In FC the calling block push the variable into OBstack (limited in size) where with FBs, variable are passedusing instance DB. This is done in STEP7 language editors (STL, LAD) using AR2 register behind the scene.

Dec