Increment And Decrement Instructions - Siemens Simatic S7-200 System Manual

Instruction Set

10.7 Increment and Decrement Instructions

Increment Byte, Decrement Byte
L
A
INC_B
D
EN
IN
DEC_B
EN
IN
S
INCB
T
L
DECB
212 214
Increment Word, Decrement Word
L
A
INC_W
D
EN
IN
DEC_W
EN
IN
S
INCW
T
L
DECW
212 214
10-66
The Increment Byte and Decrement Byte instructions add or
subtract 1 to or from the input byte.
Operands:
OUT
OUT
In LAD:
In STL:
OUT
OUT
Increment and decrement byte operations are unsigned.
Note: When programming in LAD, if you specify IN to be the
same as OUT, you can reduce the amount of memory required.
215 216
These instructions affect the following Special Memory bits:
SM1.0 (zero); SM1.1 (overflow)
The Increment Word and Decrement Word instructions add or
subtract 1 to or from the input word.
Operands:
OUT
OUT
In LAD:
In STL:
OUT
OUT
Increment and decrement word operations are signed
(16#7FFF > 16#8000).
Note: When programming in LAD, if you specify IN to be the
215 216
same as OUT, you can reduce the amount of memory required.
These instructions affect the following Special Memory bits:
SM1.0 (zero); SM1.1 (overflow); SM1.2 (negative)
IN: VB, IB, QB, MB, SMB, AC,
Constant, *VD, *AC, SB
OUT: VB, IB, QB, MB, SMB, AC,
*VD, *AC, SB
IN + 1 = OUT
IN - 1 = OUT
OUT+ 1 = OUT
OUT - 1 = OUT
IN: VW, T, C, IW, QW, MW, SMW, AC,
AIW, Constant, *VD, *AC, SW
OUT: VW, T, C, IW, QW, MW, SMW, AC,
*VD, *AC, SW
IN + 1 = OUT
IN - 1 = OUT
OUT + 1 = OUT
OUT - 1 = OUT
S7-200 Programmable Controller System Manual
C79000-G7076-C230-02