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125
FX
3G
/FX
3U
/FX
3UC
Series Programmable Controllers
Programming Manual - Basic & Applied Instruction Edition
4 Devices in Detail
4.8 High Speed Counter [C] (FX3G PLCs)
1
Int
roduct
ion
2
O
ver
view
3
In
str
uc
tion
Li
st
4
D
evices
in D
etail
5
Spec
ified t
he
D
evice &
C
onst
ant
6
Bef
ore
Pr
ogr
am
m
ing
7
B
asic
In
st
ru
ct
io
n
8
FN
C
00-FN
C
09
P
rogr
am
F
low
9
FN
C
10
-FN
C
19
Mo
ve
&
Co
mp
are
10
FNC2
0-F
NC2
9
Ar
ith.
&
Logic
O
per
ation
4.8.2
Input assignment for high speed counters
Inputs X000 to X007 are assigned as shown in the table below according to each high speed counter number.
When a high speed counter is used, the filter constant of a corresponding input number in the main unit
automatically changes (X000, X001, X003 and X004: 10
µ
s, X002, X005, X006 and X007: 50
µ
s). Input
terminals not used for high speed counters, however, can be used as general inputs.
→
For the input specifications of the main unit, refer to the Hardware Edition of the main unit.
U: Up-counting input
D: Down-counting input
A: A phase input
B: B phase input
R: External reset input
S: External start input
Restriction to overlap input numbers
• Inputs X000 to X007 are used for high speed counters, input interrupt, pulse catch, SPD/ZRN/DSZR
instructions and general-purpose inputs. When assigning functions, there should be no overlap between
those input terminals.
For example, when C251 is used, X000 and X001 are occupied. As a result, "C235, C236, C241, C244,
C246, C247, C249, C252 and C254", "input interrupt pointers I000 and I101", "pulse catch contacts M8170
and M8171" and "SPD, ZRN and DSZR instructions using X000 and/or X001" cannot be used.
Counter No.
Input terminal assignment
X000
X001
X002
X003
X004
X005
X006
X007
1-phase
1-count
input
C235
U/D
C236
U/D
C237
U/D
C238
U/D
C239
U/D
C240
U/D
C241
U/D
R
C242
U/D
R
C243
U/D
R
C244
U/D
R
S
C245
U/D
R
S
1-phase
2-count
input
C246
U
D
C247
U
D
R
C248
U
D
R
C248(OP)
U
D
C249
U
D
R
S
C250
U
D
R
S
2-phase
2-count
input
C251
A
B
C252
A
B
R
C253
A
B
R
C253(OP)
A
B
C254
A
B
R
S
C254(OP)
A
B
C255
A
B
R
S