756
Table Data Processing Instructions Section 3-17
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 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.
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
D00000
&3
D00100
000000
A
B
C
D00000
D00001
D00002
D00003
D00004
D00005
D00006
D00007
D00008
D00009
B
C
C
D00000
D00001
D00002
D00003
D00004
D00005
D00006
D00007
D00008
D00009
D00100
A
−3
−1
PLC memory
address
Stack
pointer
Stack pointer
Last word
in stack
Stack
pointer
Stack pointer
Last word
in stack
PLC memory address
of last word in the stack
The stack pointer is decremented
by 1 after the data is deleted.
(Delete/output)
-1
PLC memory address
of last word in the stack
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