99
FX
3U
/FX
3UC
Series Programmable Controllers
Programming Manual - Basic & Applied Instruction Edition
4 Devices in Detail
4.7 High Speed Counter [C]
1
In
troduct
io
n
2
Ov
e
rv
ie
w
3
In
st
ru
ct
ion
Li
st
4
D
evi
ce
s
in
De
ta
il
5
Speci
fied t
h
e
D
evi
ce &
C
onst
a
nt
6
Bef
o
re
Pr
ogr
a
m
m
ing
7
Bas
ic
In
st
ru
cti
o
n
8
FNC0
0
-FNC0
9
P
ro
g
ra
m F
lo
w
9
FNC1
0
-FNC1
9
M
ov
e
&
C
om
par
e
10
FNC
20-
FNC
2
9
Ar
ith.
&
Logi
c
O
per
at
io
n
4.7.10
Response frequency of high speed counters
1. Response frequency of hardware counters
The table below shows the maximum response frequency of hardware counters.
When hardware counters are handled as software counters in some operating conditions, Their maximum
response frequency becomes equivalent to that of software counters, and thus hardware counters are subject
to restrictions in total frequency.
→
For the conditions in which hardware counters are handled as software counters,
refer to the previous page.
2. Response frequency and total frequency of software counters
The table below shows the maximum response frequency and total frequency of software counters.
When the HSZ or HSCT instruction is used in a program, both the maximum response frequency and the total
frequency are limited for all software counter without regard to operands of these instructions. When
examining a system or creating a program, consider the contents of limitation, and use software counters
within the allowable range of maximum response frequency and total frequency.
→
For the conditions handled as software counters, refer to the previous page.
1) When special analog adapters and FX
3U
/FX
3UC
Series special function blocks/units are not used
*1.
When an index register is added to a counter number specified in HSCS, HSCR, HSZ or HSCT
instruction, all hardware counters are switched to software counters.
*2.
The high speed counters C244 (OP) and C245 (OP) can count up to 10 kHz.
Counter No.
Maximum response frequency
Main unit
FX
3U
-4HSX-ADP
1-phase 1-counting input
C235, C236, C237, C238, C239, C240
100 kHz
200 kHz
C244(OP), C245(OP)
10 kHz
1-phase 2-counting input
C246, C248(OP)
100 kHz
2-phase 2-count-
ing input
1 edge count
C251, C253
50 kHz
100 kHz
4 edge count
50 kHz
100 kHz
Counter type
Magnifica-
tion for
calculating
total
frequency
Response frequency and total frequency according to instruction use condition
Software
counter
Following
software
counter with
HSCS, HSCR,
HSZ or HSCT
instruction
*1
When HSZ and HSCT
instructions are not
used
When only HSCT
instruction is used
When only HSZ
instruction is used
When both HSZ and HSCT
instructions are used
Maximum
response
frequency
(kHz)
Total
frequency
(kHz)
Maximum
response
frequency
(kHz)
Total
frequency
(kHz)
Maximum
response
frequency
(kHz)
Total
frequency
(kHz)
Maximum
response
frequency
(kHz)
Total
frequency
(kHz)
1-phase
1-counting input
C241,
C242,
C243,
C244,
C245
C235, C236,
C237, C238,
C239, C240
×
1
40
80
30
60
40 - (Num-
ber of
instruc-
tion)
*2
80
−
1.5
×
(Num
ber of
instruc-
tion)
30-(Number
of instruc-
tion)
*2
60
−
1.5
×
(Num
ber of
instruc-
tion)
−
C244(OP),
C245(OP)
×
1
10
10
1-phase
2-counting input
C247,
C248,
C249,
C250
C246,
C248(OP)
×
1
40
30
2-
phase
2-
count-
ing
input
1 edge
count
C252,
C253(OP),
C254,
C255
C251, C253
×
1
40
30
4 edge
count
×
4
10
7.5
(40-Num-
ber of
instruc-
tion)
÷
4
(30-Number
of instruction)
÷
4