344
FX3G/FX3U/FX3GC/FX3UC Series
Programming Manual - Basic & Applied Instruction Edition
13 High-Speed Processing – FNC 50 to FNC 59
13.4 FNC 53 – HSCS / High-Speed Counter Set
Operation
When the current value of the high-speed counter C255 changes from "99" to "100" or from "101" to "100", Y010 is set
to ON (output refresh).
Related instructions
The following instructions can be combined with high-speed counters:
Cautions
1. Selection of the count comparison method
1) FX3U/FX3UC PLC
When the HSCS instruction is used in FX3U/FX3UC PLCs, hardware counters (C235, C236, C237, C238, C239,
C240, C244 (OP), C245 (OP), C246, C248 (OP), C251 and C253) are automatically switched to software
counters, and the maximum frequency and total frequency of each counter are affected.
Refer to the counting operation described below, and select according to the contents of control whether to use
HSCS instruction or general-purpose comparison instruction.
a) Case to select DHSCS instruction
- When the output should be given when the counting result becomes equivalent to the comparison value
regardless of the scan time of the PLC
b) Cases to select a general-purpose comparison instruction
- When the frequency is beyond the counting performance of software counters (and below the counting
performance of hardware counters)
- When counting is regarded as important, but the effect of the scan time can be ignored in operations
according to the counting result
- When the number of an instruction is more than 32
Instruction FNC No. Instruction name
DHSCS FNC 53 High-speed counter set
DHSCR FNC 54 High-speed counter reset
DHSZ FNC 55 High-speed counter zone compare
DHCMOV FNC189 High-speed counter move
DHSCT FNC280 High-speed counter compare with data table
M8000
RUN monitor
C255
K2,147,483,647
FNC 53
DHSCS
K100 C255 Y010
=K100 C255 Y010
→
Set to ON.
Comparison
value
Comparison
source
Output
destination
M8000
FNC189
DHCMOV
C251 D100 K0
SET Y010
FNC229
LDD<=
K100 D100
FNC 50
REF
Y010 K8
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