Neg (Create Twos Complement) Instruction; Inc (Increment) And Dec (Decrement) Instructions - Siemens S7-1200 System Manual

Basic instructions
7.5 Math functions
7.5.4

NEG (Create twos complement) instruction

Table 7- 44 NEG (create twos complement) instruction
LAD / FBD SCL
-(in);
For LAD and FBD: Click the "???" and select a data type from the drop-down menu.
1
Table 7- 45 Data types for parameters
Parameter Data type
IN SInt, Int, DInt, Real, LReal, Constant
OUT SInt, Int, DInt, Real, LReal
The IN and OUT parameters must be the same data type.
1
Table 7- 46 ENO status
ENO Description
1 No error
0 The resulting value is outside the valid number range of the selected data type.
Example for SInt: NEG (-128) results in +128 which exceeds the data type maximum.
7.5.5

INC (Increment) and DEC (Decrement) instructions

Table 7- 47 INC and DEC instructions
LAD / FBD SCL
in_out := in_out + 1;
in_out := in_out - 1;
For LAD and FBD: Click the "???" and select a data type from the drop-down menu.
1
232
Description
The NEG instruction inverts the arithmetic sign of the value at parameter IN and stores
the result in parameter OUT.
1
Description
Increments a signed or unsigned integer number value:
IN_OUT value +1 = IN_OUT value
Decrements a signed or unsigned integer number value:
IN_OUT value - 1 = IN_OUT value
Description
Math operation input
Math operation output
S7-1200 Programmable controller
System Manual, 03/2014, A5E02486680-AG