Mitsubishi Electric MELSEC iQ-R Series Programming Manual page 23

Input variables, output variables, and input/output variables
Input variables, output variables, and input/output variables need to be defined in function blocks.
A function block can output multiple operation results. It can also be set not to output operation results.
Instance
SR
_S1 Q1
RESET
(1)
Instance
CTD
CD Q
LOAD CV
PV
For the classes in which input variables, output variables, and input/output variables can be set, refer to the following.
Page 39 Classes
Internal variables
Function blocks use internal variables. For each instance of a function block, labels are assigned to the different areas. Even
though the same label names are used, different states are held for each instance.
Ex.
Instance A
Function block
bLabel1
bLabel10
Contact
uLabel12
uLabel2
Set value
cdLabel11
Current value
The above function block starts counting when the input variables turn on and turns on the output variable when the current
value held in the internal variable reaches the set value. Even though the same function block is used, the output timings differ
because the instances A and B hold different states.
For the classes in which internal variables can be set, refer to the following.
Page 39 Classes
External variables and public variables
Function blocks can use external variables and public variables.
For the classes in which external variables and public variables can be set, refer to the following.
Page 39 Classes
Instance
SAMPLE_FB1
IN_Bool
iTim
lCnt
bLabel4
bLabel13 bLabel3
Counting-up
uLabel5
(1) The operation result(s) is output.
(2) No operation result is output.
(2)
Instance B
Function block
bLabel10
Contact bLabel13
uLabel12
Counting-up
Set value
cdLabel11
Current value
3 PROGRAM ORGANIZATION UNITS
bLabel6
3.3 Function Blocks (FB)
3
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