Byte Increment and Decrement Integer Math

Inputs/Outputs Operands Data Types
IN VB, IB, QB, MB, SB, SMB, LB, AC, Constant, *VD, *AC, *LD BYTE
OUT VB, IB, QB, MB, SB, SMB, LB, AC, *VD, *AC, *LD BYTE

Memory Ranges ENO Errors Instruction Support for S7-200 CPUs SIMATIC/International Mnemonics
The Increment Byte and Decrement Byte instructions add or subtract 1 to or from the input byte (IN) and place the result into the variable specified by OUT.

Increment and decrement byte operations are unsigned.

In LAD and FBD: IN + 1 = OUT

IN - 1 = OUT

In STL: OUT + 1 = OUT

OUT - 1 = OUT

Error Conditions that Set ENO = 0:

SM1.1 (overflow), SM4.3 (run-time), 0006 (indirect address)

These instructions affect the following Special Memory bits:

SM1.0 (zero); SM1.1 (overflow)