Jump/Return
A jump is inserted in the Safety FBD Editor using the Insert Jump command.
A Return is added using the Insert Return command.
The sequential processing order of the POU is interrupted by a conditional jump. If the jump condition is TRUE, the jump takes place to a network marked by the label. (Insert Label)
The processing order of the POU is interrupted with a conditional Return statement. The POU is quit when the return condition is fulfilled.
Tip
Jumps and returns are permitted only as conditional forward jumps and conditional returns. They are possible only in the Extended programming level. In general no jumps/returns are permitted in the Basic programming level.
Display of a jump in the editor: 
, jump at a SAFE output: 
.
Conditions for jump/return
Conditional forward jumps and returns are permitted only at the end of the network (in the case of multiple assignments after the final assignment)
A network with a label must exist within the same POU as the jump destination.
The jump destination network must lie behind the network with the jump.
The jump destination may not be located in a commented-out network.
The condition of a jump/return must be Boolean.
Important
Conditional forward jumps and returns are allowed in the sense of PLCopen "safety software" only as error jump and for the implementation of state machines.
Important
The careless use of conditional jumps and returns can lead to the loss of the fail-safe property of SAFExxx variables. No warning is generated by the safety checker for such constructs.
Jumps with safe condition are uncritical in this regard.
A conditional jump, which depends on an unsafe value and has an assignment to a SAFExxx variable as its jump destination, allows an unsafe input to influence a safe output. The following rule applies to this:
It is necessary to determine all assignments to SAFExxx variables that are destinations of conditional jumps that depend on unsafe variables. Care must be taken that the safety of the machine is guaranteed in all cases.