PID block/OBs

Hi All!
Is there any rule or need that PID blocks have to be called in any other OBs other than OB1.I have started to use it OB1,almost all my blocks,motors,scaling,PID,unscaling,Indications.
I din use any FB since there are very less number motors though i tried earlier in which i had prob with enable input.i called the Motor block.In the simulation mode when the enable bit is simulated as 1,the CPU goes to stop mode.So i stopped researching
In STL languauge,an Enable input is can be activated by direct symbol "TRUE",while in FBD language a '1' or TRUE in enable input is not activated,only bits can be assigned.Why

Hello,

Look at What should you watch out for when calling and assigning parameters to the controller functions in function blocks (S)FB41, (S)FB42 and (S)FB43? There you find details about your issue. And of course links for examples using PID FBs.

Hope this will helps.

Best regards

Hristo Mihalev