369
FX
3G
/FX
3U
/FX
3UC
Series Programmable Controllers
Programming Manual - Basic & Applied Instruction Edition
13 High Speed Processing – FNC 50 to FNC 59
13.4 FNC 53 – HSCS / High Speed Counter Set
11
FNC3
0-F
NC3
9
R
otati
on and
Shif
t
12
FNC4
0-F
NC4
9
D
ata
O
per
ati
on
13
FN
C
50-FN
C
59
H
igh Speed
Pr
ocess
ing
14
FM
C
60-
FN
C
69
H
andy
In
st
ru
ct
ion
15
FNC7
0-F
N
C7
9
Ex
ter
nal
FX
I/O
D
evice
16
FN
C
80-FN
C
89
Ext
ernal FX
De
vic
e
17
FN
C
100-
FN
C
109
Da
ta
Transf
er 2
18
FN
C
110-
FN
C
139
Fl
oati
ng Poi
nt
19
FN
C
140
-F
N
C
14
9
Da
ta
O
per
ati
on 2
20
FN
C
150-
FN
C
159
Posit
ioning
C
ontr
ol
4. Caution on the counting operation when the current value is changed
An instruction for the high speed counter gives the comparison result when a pulse is input to the input (X) of
the high speed counter.
However, the comparison result is not given when the current value of the high speed counter is changed in
the following method:
1) Change method (examples)
a) Overwriting the contents of a word device used as the comparison value using DMOV instruction, etc.
b) Resetting the current value of a high speed counter in a program
2) Operation
Even if the condition for setting the output to ON or OFF is given as the comparison result, the
comparison result does not change when an instruction is simply driven.
5. Reset operation by an external terminal [M8025
*1
: HSC (external reset) mode]
For a high speed counter equipped with an external reset terminal (R) such as C241, an instruction is
executed and the comparison result is output at the rising edge of the reset input signal.
In FX
3G
PLCs, high speed counters operate in the HSC (external reset) mode without regard to the status of
M8025.
1) Program
If an instruction for the high speed counter is used while M8025
*1
is driven, the instruction is executed
again when the current value of the high speed counter C241 is cleared by an external reset terminal.
And the comparison result is output even if a counting input is not given.
*1.
M8025 is cleared when the PLC mode is changed from RUN to STOP.
It is not necessary to drive M8025 in FX
3G
PLCs.
2) Operation
When the external reset input X001 turns ON while the current value of C241 is "100", for example, the
current value of C241 is reset to "0". And Y000 is reset at this time even if a counting input is not given.
External reset
terminal for C241
M8025 *1 External reset mode
FNC 54
DHSCR
K 0
C241
Y000
C241
K9,999
M8000
RUN monitor
X001