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743
Table Data Processing Instructions
Section 3-17
3-17-14 STACK SIZE READ: SNUM(638)
Purpose
Counts the amount of stack data (number of words) in the specified stack.
This instruction is supported by CS1-H, CJ1-H, CJ1M, and CS1D CPU Units
only.
Ladder Symbol
Variations
Applicable Program Areas
Operands
TB through TB+3: Stack control words
The first four words of the stack contain the PLC memory address of the last
word in the stack and the stack pointer (the PLC memory address of the next
available word in the stack.)
TB+4 through TB+(N–1): Data storage region
The remainder of the stack is used to store data.
SNUM(638)
TB
D
TB: First stack address
D: Destination word
Variations
Executed Each Cycle for ON Condition
SNUM(638)
Executed Once for Upward Differentiation
@SNUM(638)
Executed Once for Downward Differentiation
Not supported.
Immediate Refreshing Specification
Not supported.
Block program areas
Step program areas
Subroutines
Interrupt tasks
OK
OK
OK
OK
TB
0
15
TB+1
0
15
TB+2
0
15
TB+3
0
15
PLC memory address of the last
word in the stack (rightmost 4 digits)
PLC memory address of the last
word in the stack (leftmost 4 digits)
Stack pointer (rightmost 4 digits)
(Initial value is the rightmost 4 digits of
the PLC memory address for TB+4.)
Stack pointer (leftmost 4 digits)
(Initial value is the leftmost 4 digits of
the PLC memory address for TB+4.)
15
0
TB+4
TB+(N–1)
Data storage region
Summary of Contents for SYSMAC CS1D-CPU**
Page 3: ...iv...
Page 29: ...xxx...
Page 185: ...146 List of Instructions by Function Code Section 2 4...
Page 1389: ...1350 CJ series Instruction Execution Times and Number of Steps Section 4 2...
Page 1390: ...1351 Appendix A ASCII Code Table ASCII SP Four leftmost bits Four rightmost bits...
Page 1391: ...1352 ASCII Code Table Appendix A...