Omron CP - PROGRAMMING MANUAL 05-2007 - Page 608

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Table Data Processing Instructions Section 3-16
Examples When CIO 0.00 is ON in the following example, FIFO(633) reads the content
of D4 (TB+4 for the stack beginning at D0) and writes that data to D300.
After the data is written to D300, the stack pointer is decremented by one and
the remaining data is shifted down. (The content of D5 is shifted to D4 and the
content of D6 is shifted to D5.)
3-16-4 LAST IN FIRST OUT: LIFO(634)
Purpose Reads the last word of data written to the specified stack (the newest data in
the stack).
Ladder Symbol
Variations
Applicable Program Areas
TB:
D: D300
TB
0.00
D0
D300
D0
D1
D2
D3
D4
D5
D6
D7
D8
D9
Read by FIFO(633).
Stack pointer
PLC memory address
of last word in stack
Last word
in stack
Stack
pointer
D: D300
–1
D0
D1
D2
D3
D4
D5
D6
D7
D8
D9
Last word
in stack
Stack
pointer
PLC memory address
of last word in stack
Stack pointer
LIFO(634)
TB
D
TB: First stack address
D: Destination word
Variations Executed Each Cycle for ON Condition LIFO(634)
Executed Once for Upward Differentiation @LIFO(634)
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