Mitsubishi Electric MELSEC FX3U Programming Manual page 369

FX /FX /FX Series Programmable Controllers
3G 3U 3UC
Programming Manual - Basic & Applied Instruction Edition
2) FX PLCs
3G
When the HSCS instruction is used in FX
Refer to the counting operation described below, and select according to the contents of control whether
to use the HSCS instruction or a general-purpose comparison instruction.
a) Case to select the HSCS 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
FNC229
LDD<=
2. Device specification range
Only high speed counters (C235 to C255) can be specified as
3. Only 32-bit operation instructions are available.
Because instructions for high speed counters are dedicated to 32 bits, make sure to input "DHSCS (FNC 53)".
4. Priority order in operation among HSCS (FNC 53), HSCR (FNC 54), and HSZ (FNC 55)
instructions for a same high speed counter
→ For details, refer to "6. Priority order in operations among HSCS (FNC 53), HSCR (FNC 54), and HSZ
5. Reset operation by an external terminal
→ For details, refer to "5. Reset operation by an external terminal" in Subsection 13.4.1.
6. For other cautions on using HSCS instruction, refer to the description later.
Program example
With regard to the current value of a counter, different outputs (Y) are arbitrary set to ON by two values.
M8000
RUN monitor
C255
0
Y010
Y011
K100 C251
FNC 50
REF
(FNC 55) instructions for the same high speed counter" in Subsection 13.4.1.
K2,147,483,647
C255
S S
1 2
FNC 53
K100 C255
DHSCS
S S
1 2
FNC 53
K150 C255
DHSCS
Comparison Comparison
value source
150
... 149
101
100
... 99
13 High Speed Processing – FNC 50 to FNC 59
13.4 FNC 53 – HSCS / High Speed Counter Set
PLCs, the total frequency of each counter is affected.
3G
SET Y010
Y010 K8
.
S
→ For details, refer to the next page.
Set the maximum counting value of
high speed counter.
D
C255 = K100 → Y010 = ON
Y010
D
C255 = K150 → Y011 = ON
Y011
Output
destination
151
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