Mitsubishi Electric MELSEC iQ-F FX5 Programming Manual page 55

■The operation of a return unit
A return unit operates differently depending on whether a program, function, and/or function block used there.
Program unit to use
Program
Function
Function block
If a return element is used in a macro-type function block, do not place two or more function block elements of the same
instance name.
A local label "_SYSTEM_RETURN" is automatically registered when a program using a return element is converted.
The local label "_SYSTEM_RETURN" has the following operational limitations:
Operation on the label automatically registered
Changing the label name
Changing the data type
Changing the class
Deleting the label
Changing the line of registration
*1 If the program is converted again after change or deletion, a new local label is registered.
■Connector unit
Use a connector element to place the program within the display area or print area of the FBD/LD editor.
Var1 Var2
CONNECTOR
Connecting wire
This is the wire to connect the connecting points between FBD unit, LD unit, and common unit.
After units are connected, the data is transferred from the left end to the right end. The data types of the connected units need
to be the same.
Connecting point
This is a terminal point to use a connecting wire to connect FBD unit, LD unit, and common unit.
The point on the left side of each unit is the input side, while the point on the right side represents the output side.
Unit Input connecting
point
Contact
Variable
Function
The connecting point is hidden after connecting a wire.
The execution of the program unit is terminated.
The function is terminated, and the step goes back to the one next to the instruction that has called the function.
The function block is terminated, and the step goes back to the one next to the instruction that has called the function
block.
Var3 Var4
Var6
Output connecting
point
The return value is not
shown on a function.
Permitted/Prohibited
*1
Prohibited
Prohibited
Prohibited
*1
Prohibited
Permitted
Var5
CONNECTOR
Var7 Var8 Coil1
Unit Input connecting
point
Coil

Constant
Function Block
Output connecting
point
7 FBD/LD language
53
7.1 Configuration
7