373
FX
3G
/FX
3U
/FX
3UC
Series Programmable Controllers
Programming Manual - Basic & Applied Instruction Edition
13 High Speed Processing – FNC 50 to FNC 59
13.5 FNC 54 – HSCR / High Speed Counter Reset
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
2) FX
3G
PLCs
When the HSCR instruction is used in FX
3G
PLCs, the total frequency of each counter is affected.
Refer to the counting operation described below, and select according to the contents of control whether
to use the HSCR instruction or a general-purpose comparison instruction.
a) Case to select the HSCR instruction
-
When the output should be given if the counting result becomes equivalent to the comparison
value without regard to the scan time of the PLC
b) Cases to select a general-purpose comparison instruction
-
When counting is regarded as important, but the effect of the scan time can be ignored in
operations according to the counting result
-
When an instruction is used 6 times or more
2. Only 32-bit operation instructions are available.
Because instructions for high speed counters are dedicated to 32 bits, make sure to input "DHSCR (FNC 54)".
3. Priority order in operation among HSCS (FNC 53), HSCR (FNC 54), and HSZ (FNC 55)
instructions for the same high speed counter
→
For details, refer to "6. Priority order in operations among HSCS (FNC 53), HSCR (FNC 54), and HSZ
(FNC 55) instructions for the same high speed counter" in Subsection 13.4.1.
4. Reset operation by an external terminal
→
For details, refer to "5. Reset operation by an external terminal [M8025*1: HSC (external reset)
mode]" in Subsection 13.4.1.
5. Other cautions on using HSCR instruction
→
For details, refer Subsection 13.4.1.
Program example
1. Example of self-reset circuit
When the current value of C255 becomes "400", C255 is immediately reset. Its current value becomes "0",
and the output contact is set to OFF.
FNC229
LDD<=
K10000
C251
RST
Y010
Y010
K8
FNC 50
REF
M8000
C255
K300
FNC 54
DHSCR
K400
C255
C255
Reset value of DHSCR
400
Count-up value
300
Current value
of C255
Output contact
of C255
Comparison
value
Comparison
source
Output
destination
M8000
RUN monitor