Mitsubishi Electronics FX3G User Manual

Page of 964
283
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
10.6 FNC 25 – DEC / Decrement
1
Introdu
ction
2
Ov
ervi
ew
3
Instruction 
Li
st
4
D
evices 
in Det
ai
l
5
Specifi
ed the
De
vice
 &
 
C
onst
ant
6
Bef
ore
 
Pr
og
ra
mmi
ng
7
Bas
ic 
Instruction
8
FN
C00-FN
C0
9
Program Fl
ow
9
FNC
10-FN
C19
Mov
e & Com
pare
10
FNC
20-FNC
29
Arith. & Lo
gi
Operati
on
10.6
FNC 25 – DEC / Decrement
Outline
This instruction decrements the data of a specified device by "1".
1. Instruction format
2. Set data
3. Applicable devices
S
1: This function is supported only in FX
3G
/FX
3GC
/FX
3U
/FX
3UC
 PLCs.
S
2: This function is supported only in FX
3U
/FX
3UC
 PLCs.
Explanation of function and operation
1. 16-bit operation (DEC and DECP)
The contents of 
 are decremented by "1", and the decremented result is transferred to 
.
2. 32-bit operation (DDEC and DDECP)
The contents of [
+1, 
] are decremented by "1", and the decremented result is transferred to [
+1,
].
Cautions
1. Flag operations
1) 16-bit operation
When "
−32768" is decremented by "1", the result is "+32767".  Flags (zero, carry and borrow) are not activated at
this time.
2) 32-bit operation
When "
−2,147,483,648" is decremented by "1", the result is "+2,147,483,647".  Flags (zero, carry and borrow) are
not activated at this time.
Operand type
Description
Data type
Word device number storing data to be decremented by "1"
16- or 32-bit binary
Oper-
and 
Type
Bit Devices
Word Devices
Others
System User
Digit Specification
System User
Special 
Unit
Index
Con-
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
DDEC
DDECP
Mnemonic
Operation Condition
P
FNC 25
DEC
D
16-bit Instruction
 3 steps DEC
DECP
Mnemonic
Operation Condition
Continuous
Operation
Pulse (Single)
Operation
32-bit Instruction
 5 steps
Continuous
Operation
Pulse (Single)
Operation
  D
  D
   
D
   
D
Command
input
FNC 25
DECP
− 1 →
   
D
   
D
   
D
   
D
Command
input
FNC 25
DDECP
[          +1,          ] 
− 1 → [          + 1,          ]