Description

RETURN instructions can be used in DFBs (derived function blocks) and in SRs (subroutines).

RETURN instructions can not be used in the main program.

• In a DFB, a RETURN instruction forces the return to the program which called the DFB.

  • The rest of the DFB section containing the RETURN instruction is not executed.

  • The next sections of the DFB are not executed.

  The program which called the DFB will be executed after return from the DFB.

  If the DFB is called by another DFB, the calling DFB will be executed after return.

• In a SR, a RETURN instruction forces the return to the program which called the SR.

  • The rest of the SR containing the RETURN instruction is not executed.

  The program which called the SR will be executed after return from the SR.