Mitsubishi Electric MELSEC iQ-F Series Programming Manual page 16

Input variables and output variables
Input and output variables can be defined in functions. Output data which is different from the return value can be assigned to
the output variable.
Ladder program
Input variables are set in the VAR_INPUT class and output variables are set in the VAR_OUTPUT class.
Variables defined in the function are overwritten every time the function is called.
To hold the data in the variables, create a program by using function blocks or so that the data in the output
variable is saved in another variable.
EN and ENO
EN (enable input) and ENO (enable output) can be appended to a function to control execution processing.
• Set a boolean variable used as an execution condition of a function to EN.
• A function with EN is executed only when the execution condition of EN is TRUE.
• Set a boolean variable used to output a function execution result to ENO.
The following table lists the ENO states and operation results according to the EN states.
EN
TRUE (executed)
FALSE (not executed)
• Setting an output label to ENO is not always required for the program written in ladder or FBD/LD.
• When EN/ENO is used in a standard function, the function with EN is represented by "function-name_E".
3 PROGRAM ORGANIZATION UNITS
14
3.2 Functions (FUN)
FBD/LD program
(1)
(2)
(3)
The return value of the function is not displayed.
ENO
TRUE
FALSE
(1)
(2)
(3)
Operation result
Operation result output value
Undefined value
(1) Function name
(2) Input variable
(3) Output variable