Mitsubishi Electric MELSEC Q Series Structured Programming Manual page 35

(2) Internal variables
A function does not use internal variables. It uses devices assigned directly to each input
variable and repeats operations.
(a) A program that outputs the total of three input variables (When using a function (FUN1))
X0
D109 D109
D110
D110
D111 D111
A function block uses internal variables. Different devices are assigned to the internal
variables for each instance of function blocks.
(b) Programs that output the total of three input variables (When using function blocks)
Instance A
Function block
D10 D6200
D11 D6201
D12 D6202
Function
FUN1 D120
D10
D6203 D13
D11
D12
4.2.8 Functions, function blocks, and operators
Instance B
Function block
D6210
D6213
D6211
D6212
4.2 POUs
4
D13
4-11