Mitsubishi MELSEC-Q/L

247
NEG, NEGP, DNEG, DNEGP
1
2
3
4
6
7
8
6.3 Data conversion instructions 6.3.11 NEG, NEGP, DNEG, DNEGP
Function
NEG
(1) Reverses the sign of the 16-bit device designated by and stores at the device designated by .
(2) Used when reversing positive and negative signs.
DNEG
(1) Reverses the sign of the 32-bit device designated by and stores at the device designated by .
(2) Used when reversing positive and negative signs.
Operation Error
(1) There is no operation error in the NEG(P) or DNEG(P) instruction.
Program Example
(1) The following program calculates a total for the data at D10 through D20 when XA goes ON, and seeks an absolute
value if the result is negative.
[Ladder Mode]
[List Mode]
D D
16 bit
Before execution
Sign conversion
b15
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
b0
0
0 0 0 0 0 0 0 0 0 0 0 0 000
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
b15
1 1 1 1 1 1 1
b0
-21846
0000000
1
D
D
0
A
fter execution
21846
D D
32 bit
b31
1
Before
execution
1 1 1 1 1 1
0
1
0 0
1
00
b0
000 0 0 0 0 0 0 0 0 0 00
111 1 1 1 1 0 1 0 0 1 00
1
b31
0 0 0 1 1 1 0
b0
Sign
conversion
-
A
fter
execution
0000 010
D
D
-218460
218460
M3 is turned ON if D10 < D20.
Executes "D10 - D20".
Calculates the absolute value
(complement of 2) when M3 is ON.
Step
Instruction
Device