105
Procedures
Section 3-2
Method Used for Checking Addresses Internally Allocated to Variables
Checking the Status of
Addresses Internally
Allocated to Variables
The following procedure can be used to check the number of addresses allo-
cated to variables and the number still available for allocation in the function
block instance areas.
1,2,3...
1.
Select the instance in the Ladder Section Window, right-click, and select
Memory Allocation - Function Block/SFC Memory - Function
Block/SFC Memory Statistics
from the PLC Menu.
2.
The Function Block/SFC Memory Statistics Dialog Box will be displayed as
shown below. Check address usage here.
Optimizing Function
Memory
When a variable is added or deleted, addresses are automatically re-allocated
in the variables’ instance area. Consecutive addresses are required for each
instance, so all of the variables will be allocated to a different block of
addresses if the original block of addresses cannot accommodate the change
in variables. This will result in an unused block of addresses. The following
procedure can be used to eliminate the unused areas in memory so that
memory is used more efficiently.
1,2,3...
1.
Select the instance in the Ladder Section Window, right-click, and select
Memory Allocation - Function Block/SFC Memory - Optimize Func-
tion/SFC Memory
from the PLC Menu.
The following dialog box will be displayed.
a
b
c
sample FB [FunctionBlock1]
N/A [Auto]
a
BOOL
W400.00
b
BOOL
W401.00
c
BOOL
W401.02
Instance registered in global
symbol table under instance name.
Name
Address/
Value
Type
Name
Address
Type
Name
Address
Type
Inputs
Outputs
FM Instance Memory Dialog Box
Instance name
Addresses used for function
block internal variables
Right-click and select
Function
Block Memory Address.
Instance of function block definition A,
instance name: sample
Program
The total number
of words in each
interface area.
The number
of words
already used.
The number of
words still available.
Summary of Contents for CX-PROGRAMMER V8.1
Page 3: ...iv...
Page 5: ...vi...
Page 7: ......
Page 15: ...xvi...
Page 19: ...xx...
Page 25: ...xxvi Application Precautions 4...
Page 26: ...Part 1 Function Blocks...
Page 27: ......
Page 153: ...128 Procedures Section 3 2...
Page 154: ...Part 2 Structured Text ST...
Page 155: ......
Page 159: ...134 CX Programmer Specifications Section 4 2...
Page 205: ...180 Procedures Section 6 1...
Page 207: ...182 System defined external variables supported in function blocks Appendix A...
Page 229: ...204 Revision History...
Page 230: ......