608
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, SWRIT(640) writes the data in
D100 to the specified word in the stack starting at D0. In this case, the stack
pointer indicates D7 and the offset value is 3, so the data in D4 is overwritten.
Name Label Operation
Error Flag ER ON if the specified write location is not within the stack
area.
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.
SWRIT
D0
&3
D100
0.00
B
D0
D1
D2
D3
D4
D5
D6
D7
D8
D9
A
D0
D1
D2
D3
D4
D5
D6
D7
D8
D9
D100
A
−3
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
PLC memory
address
Stack pointer
Stack pointer
(Overwrite)
The stack pointer position remains
unchanged after the data is written.
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