Mitsubishi FX3G Series Programming Manual

285
FX3G/FX3U/FX3GC/FX3UC Series
Programming Manual - Basic & Applied Instruction Edition
10 Arithmetic and Logical Operation ( + , − , × , ÷ ) – FNC 20 to FNC 29
10.10 FNC 29 – NEG / Negation
1
Introduction
2
Overview
3
Instruction List
4
Devices in Detail
5
Specified the Device & Constant
6
Before Programming
7
Basic Instruction
8
FNC00-FNC09 Program Flow
9
FNC10-FNC19 Move & Compare
10
FNC20-FNC29 Arith. & Logic Operation
Program examples
The program examples below are provided to obtain the absolute value of a negative binary value.
1. Obtaining the absolute value of a negative value using NEG instruction
2. Obtaining the absolute value by SUB (subtraction) instruction
Even if NEG instruction is not used, D30 always stores the absolute value of the difference.
Negative value expression and absolute value (reference)
In PLCs, a negative value is expressed in 2’s complement.
When the most significant bit is "1", it is a negative value, and its absolute value can be obtained by NEG
instruction.
M 0
FNC 29
NEGP
D 10
M8000
FNC 44
BON
D 10 M 0 K 15
RUN monitor
In BON (ON bit check) instruction, M0 turns ON
when the bit 15 (b15 among b0 to b15) of D10 is "1".
NEGP instruction is executed for D10 only when M0
turns ON.
D10
→ D10
X000
M 10
M 11
M 12
FNC 21
SUB
D 10 D 20 D 30
FNC 21
SUB
D 20 D 10 D 30
FNC 10
CMP
D 10 D 20 M 10
(D 10) > (D 20) (D10) = (D 20) (D 10) < (D 20)
M 10 = ON M 11 = ON M 12 = ON
In the case of "D10
≥ D20",
D10
− D20 → D30.
In the case of "D10 < D20",
D20
− D10 → D30.
(D 10) = 2
0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0
(D 10) = 1
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1
(D 10) = 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
(D 10) =
− 1
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
(D 10) =
− 2
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0
1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
(D 10) =
− 32767
(D 10) =
− 32768
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1
(D 10) + 1 = 1
0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0
(D 10) + 1 = 2
0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
(D 10) + 1 = 32767
(D 10) + 1 = − 32768
1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
The absolute value can be obtained up to 32767.
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Mitsubishi FX3G Series Specifications

General

Model	FX3G Series
Power Supply	AC 100-240V or DC 24V
Program Capacity	32, 000 steps
Execution Speed	0.21 µs/basic instruction
Communication Options	RS-422, USB, Ethernet
Expansion Modules	Analog, digital, communication
Programming Language	Ladder Logic, Instruction List
Built-in Functions	High-speed counters, pulse output
Analog I/O	Available via expansion modules