Omron SYSMAC CJ - REFERENCE MANUAL 01-2008 Reference Manual page 796

Table Data Processing Instructions
Flags
Precautions
Examples
000000
SDEL
D00000
&3
D00100
Stack
pointer
Last word
in stack
Stack
pointer
Last word
in stack
Name Label
Error Flag ER
Equals Flag =
The stack must be defined in advance with SSET(630).
The address in the stack pointer must be greater than the PLC memory
address of the beginning of the data region (TB+4). An error will occur if the
stack pointer is less than the PLC memory address of TB+4, i.e., if a stack
underflow error occurs.
When CIO 000000 is ON in the following example, SDEL(642) deletes the
word at the specified address in the stack starting at D00000, outputs the
deleted data to D00100, shifts the remaining data upward, and decrements
the stack pointer.
In this case, the stack pointer indicates D00007 and the offset value is 3, so
the data is deleted from D00004. The remaining data is shifted up one word
and the stack pointer is decremented from D00007 to D00006.
PLC memory address
D00000
of last word in the stack
D00001
D00002
Stack pointer
D00003
D00004
A
D00005
B
3
D00006
C
D00007
D00008
D00009
-1
D00000 PLC memory address
of last word in the stack
D00001
D00002
Stack pointer
D00003
D00004
B
D00005
C
D00006
C
1
D00007
D00008
D00009
Operation
ON if the content of the stack pointer (TB+3 and TB+2) is
less than or equal to the PLC memory address of first
word in the data region of the stack (TB+4).
(This is a stack underflow error.)
ON if the offset value specified in C is 0 or greater than
the maximum data region size (FFFB hex).
OFF in all other cases.
ON if the output data in D is 0000.
OFF in all other cases.
PLC memory
address
(Delete/output)
D00100
The stack pointer is decremented
by 1 after the data is deleted.
Section 3-17
A
757