Functions, Function Blocks, And Operators - Mitsubishi Electric MELSEC Q Series Structured Programming Manual

4.2.8

Functions, function blocks, and operators

The following table shows differences among functions, function blocks, and operators.
Output variable assignment
Creating instances
(1) Output variable assignment
A function always outputs a single operation result. A function that does not output any
operation result or outputs multiple operation results cannot be created.
A function block can output multiple operation results. It also can be created without any
output.
An operator always outputs a single operation result. It cannot be edited.
Example
4.2 POUs
4-10
4.2.8 Functions, function blocks, and operators
Table 4.2.8-1 Differences among functions, function blocks, and operators
Item
Cannot be assigned
Internal variable Not used
Not necessary
Table 4.2.8-2 Output variable assignment
Function
Outputs one
operation result
Function Function block
Can be assigned
Used
Necessary
Function block
Outputs multiple Outputs multiple
operation results
Without any output
Operator
Cannot be assigned
Not used
Not necessary
Operator
Outputs one
operation result