Specifications

4-10
4.2 POUs
4.2.8 Functions, function blocks, and operators
4.2.8 Functions, function blocks, and operators
The following table shows differences among functions, function blocks, and operators.
Table 4.2.8-1 Differences among functions, function blocks, and operators
(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.
Table 4.2.8-2 Output variable assignment
Item Function Function block Operator
Output variable assignment
Cannot be assigned Can be assigned Cannot be assigned
Internal variable
Not used Used Not used
Creating instances
Not necessary Necessary Not necessary
Function Function block Operator
Example
Outputs one
operation result
Outputs
multiple
op
eration results
Without an
y
output
Outputs multiple
Outputs one
operation result