7 Applied Instructions
7.6 High Speed Processing
278
FXCPU Structured Programming Manual
(Basic & Applied Instruction)
Cautions
1. Selection of the counter comparison method
When the DHSCS instruction is used, the maximum frequency and total frequency of the high speed counter
are affected.
Refer to the counting operation described below, and select according to the contents of control whether to
use this instruction or general-purpose comparison instruction.
1) Case to select DHSCS instruction
- When the output should be given when the counting result becomes equivalent to the comparison value
without regard to the scan time of the PLC.
2) Cases to select a general-purpose comparison instruction
- When the required frequency is beyond the counting performance.
- 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 exceeds the allowable limit.
For FX
3U and FX3UC PLCs
For FX
0, FX0S, FX0N, FXU, FX2C, FX1S, FX1N, FX1NC, FX2N, FX2NC and FX3G PLCs
2. Device specification range
Only high speed counters can be specified as .
For details, refer to the following manual.
→ FX Structured Programming Manual (Device & Common)
3. Some restrictions to applicable devices
S1: Applicable to the FX3U and FX3UC PLCs only.
Not indexed (V, Z).
S2: Use interrupt pointer when using counter interrupt.
(Not available for the FX
0, FX0S, FX0N, FX1N, FX1S or FX3G PLC.)
→ For the counter interrupt using this instruction, refer to Section 8.6.
S3: Applicable to the FX
3U, FX3UC and FX3G PLCs only.
S4: Applicable to the FX
3U and FX3UC PLCs only.
LD<=
EN
s1
s2
ENO
Label 4
*4
SET
EN
d
ENO
Y010
REF
EN
d
n
ENO
Y010
K8
*1. This defines CN251.
M8000
DHCMOV
EN
s
n
ENO
d
K0
Label 3
*3
Label 1
*1
Label 2
*2
*2. This defines D100.
*3. This defines K100.
*4. This defines D100.
LD<=
EN
s1
s2
ENO
Label 4
*2
SET
EN
d
ENO
Y010
REF
EN
d
n
ENO
Y010
K8
Label 3
*1
*1. This defines K100.
*2. This defines CN251.
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