Omron CP - PROGRAMMING MANUAL 05-2007 - Page 647

614
Table Data Processing Instructions Section 3-16
Flags
Precautions 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.
Examples When CIO 0.00 is ON in the following example, SDEL(642) deletes the word
at the specified address in the stack starting at D0, outputs the deleted data to
D100, shifts the remaining data upward, and decrements the stack pointer.
In this case, the stack pointer indicates D7 and the offset value is 3, so the
data is deleted from D4. The remaining data is shifted up one word and the
stack pointer is decremented from D7 to D6.
Name Label Operation
Error Flag ER 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.
Equals Flag = ON if the output data in D is 0000.
OFF in all other cases.
SDEL
D0
&3
D100
0.00
A
B
C
D0
D1
D2
D3
D4
D5
D6
D7
D8
D9
B
C
C
D0
D1
D2
D3
D4
D5
D6
D7
D8
D9
D100
A
−3
−1
Last word
in stack
Last word
in stack
Stack
pointer
Stack
pointer
PLC memory address
of last word in the stack
PLC memory address
of last word in the stack
Stack pointer
Stack pointer
PLC memory
address
(Delete/output)
The stack pointer is decremented
by 1 after the data is deleted.