Mitsubishi Electronics FX3G User Manual
273
FX
3S
/FX
3G
/FX
3GC
/FX
3U
/FX
3UC
Series
Programming Manual - Basic & Applied Instruction Edition
10 Arithmetic and Logical Operation (
+, −, ×, ÷) – FNC 20 to FNC 29
10.2 FNC 21 – SUB / Subtraction
1
Introdu
ction
2
Ov
ervi
ew
ew
3
Instruction
Li
st
4
D
evices
in Det
ai
l
5
Specifi
ed the
De
vice
&
C
onst
ant
ant
6
Bef
ore
ore
Pr
og
ra
mmi
ng
ng
7
Bas
ic
ic
Instruction
8
FN
C00-FN
C00-FN
C0
9
Program Fl
ow
9
FNC
10-FN
C19
Mov
e & Com
e & Com
pare
10
FNC
20-FNC
29
Arith. & Lo
gi
c
Operati
on
10.2
FNC 21 – SUB / Subtraction
Outline
This instruction executes subtraction using two values to obtain the result (A
− B = C).
→ For the floating point subtraction instruction ESUB (FNC121), refer to Section 18.9.
1. Instruction format
2. Set data
3. Applicable devices
S1: This function is supported only in FX
3G
/FX
3GC
/FX
3U
/FX
3UC
PLCs.
S2: This function is supported only in FX
3U
/FX
3UC
PLCs.
Explanation of function and operation
1. 16-bit operation (SUB and SUBP)
The contents of
are subtracted from
in binary format, and the subtraction result is transferred to
.
• The most significant bit of each data indicates the sign (positive: 0 or negative: 1), and data is subtracted
algebraically.
5
5
− (−8) = 13
• When a constant (K) is specified in
or
, it is automatically converted into binary format.
2. 32-bit operation (DSUB and DSUBP)
The contents of [
+1,
] are subtracted from [
+1,
] in binary format, and the subtraction result
is transferred to [
+1,
].
• The most significant bit of each data indicates the sign (positive: 0 or negative: 1), and data is subtracted
algebraically.
5500
5500
− (−8540) = 14040
• When a constant (K) is specified in [
+1,
] or [
+1,
], it is automatically converted into binary
format.
Operand type
Description
Data type
Data for subtraction or word device number storing data
16- or 32-bit binary
Data for subtraction or word device number storing data
16- or 32-bit binary
Word device number storing the subtraction result
16- or 32-bit binary
Oper-
and
Type
Bit Devices
Word Devices
Others
System User
Digit Specification
System User
Special
Unit
Index
Con-
stant
stant
Real
Number
Charac-
ter String
Pointer
X Y M T C S D .b KnX KnY KnM KnS T C D
R
U \G
V Z Modify K H
E
" "
P
S1
S2
S1
S2
S1
S2
DSUB
DSUBP
Mnemonic
Operation Condition
P
FNC 21
SUB
D
16-bit Instruction
7 steps SUB
SUBP
Mnemonic
Operation Condition
Continuous
Operation
Pulse (Single)
Pulse (Single)
Operation
32-bit Instruction
13 steps
Continuous
Operation
Pulse (Single)
Pulse (Single)
Operation
S
1
S
2
D
S
1
S
2
D
S
2
S
1
D
FNC 21
SUB
S
1
S
2
− →
Command
input
D
S
1
S
2
D
S
1
S
2
S
2
S
2
S
1
S
1
D
1
D
1
FNC 21
DSUB
S
1
S
2
[ +1, ]
− [ +1, ] → [ +1, ]
Command
input
D
S
1
S
2
D
S
1
S
2
D
S
1
S
1
S
2
S
2