281
FX3G/FX3U/FX3UC Series Programmable Controllers
Programming Manual - Basic & Applied Instruction Edition
10 Arithmetic and Logical Operation (
+
,
−
,
×
,
÷
) – FNC 20 to FNC 29
10.6 FNC 25 – DEC / Decrement
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
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: This function is supported only in FX3U/FX3UC 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
XYMTCSD.b KnX KnY KnM KnS T C D R U\G VZModifyKH E ""P
3333333 S 33 3
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
D
−
1
→
D
D
D
D
D
D
Command
input
FNC 25
DDECP
D
D
[ +1, ]
−
1
→
[ + 1, ]
D
D
D