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FX3S/FX3G/FX3GC/FX3U/FX3UC Series
Programming Manual - Basic & Applied Instruction Edition
18 Floating Point – FNC110 to FNC139
18.1 FNC110 – ECMP / Floating Point Compare
11
FNC30-FNC39
Rotation and
Shift
12
FNC40-FNC49
Data Operation
13
FNC50-FNC59
High-Speed
Processing
14
FMC60-FNC69
Handy
Instruction
15
FNC70-FNC79
External FX I/O
Device
16
FNC80-FNC89
External FX
Device
17
FNC100-FNC109
Data
Transfer 2
18
FNC110-FNC139
Floating Point
19
FNC140-FNC149
Data
Operation 2
20
FNC150-FNC159
Positioning
Control
18.1 FNC110 – ECMP / Floating Point Compare
Outline
This instruction compares two data values (binary floating point), and outputs the result (larger, same or smaller) to
three consecutive bit devices.
→ For handling of floating point, refer to Subsection 5.1.3.
1. Instruction format
2. Set data
*1. When a constant (K or H) is specified, it is automatically converted from binary into binary floating point (real
number) when the instruction is executed.
3. Applicable devices
S1: "D.b" is available only in FX3U/FX3UC PLCs, and cannot be indexed with index registers (V and Z).
S2: This function is supported only in FX
3G/FX3GC/FX3U/FX3UC PLCs.
S3: This function is supported only in FX
3U/FX3UC PLCs.
Explanation of function and operation
1. 32-bit operation (DECMP and DECMPP)
The comparison value [ +1, ] is compared with the comparison source [ +1, ] as floating point
data, and one of the bits among , +1 and +2 turns ON according to the result (smaller, same or
larger).
• When a constant (K or H) is specified as [ +1, ] or [ +1, ], it is automatically converted from
binary into binary floating point (real number) when the instruction is executed.
Caution
1. Number of occupied devices
Three devices are occupied from ( , +1 and +2).
Make sure that these devices are not used for any other purpose.
Operand Type Description Data Type
Device number storing binary floating point data to be compared
Real number (binary)
*1
Device number storing binary floating point data to be compared
Head bit device number to which the comparison result is output (Three devices are
occupied.)
Bit
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
V Z Modify K H E "
"P
S2 S3
S2 S3
S1
P
FNC 110
ECMP
D
−
Mnemonic Operation Condition
16-bit Instruction
DECMP
DECMPP
Mnemonic Operation Condition
32-bit Instruction
13 steps
Continuous
Operation
Pulse (Single)
Operation
S
1
S
2
D
S
1
S
2
D
S
1
S
1
S
2
S
2
D
D
D
S
1
S
1
S
2
S
2
Command
input
FNC110
DECMP
Even if the command input turns OFF before the DECMP instruction is fully executed, to +2 hold the status.
+1
+2
S
1
S
2
D
D
D
D
D D
Turns ON in the case of
+1, ]
S
1
S
1
+1,[
S
2
S
2
" [
] ".
Turns ON in the case of
=
+1, ]
S
1
S
1
+1,[
S
2
S
2
" [ ] ".
Turns ON in the case of
] ".+1," [ ]
S
1
S
1
+1,[
S
2
S
2
>
<
D
D
D
D