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(d)
Maximum counting speed
The counter can count only when the on/off time of the input condition is longer than the execution interval of
the corresponding OUT C
The maximum counting speed is calculated by the following expression:
When T1
When T1 < T2, n =
Count input signal
The maximum counting speed can be increased by placing multiple counters within one scan.
At this time, use the direct access input (DX
Sequence
program
(4) Precautions
(a) When counting processing is suspended
If an interrupt occurs during execution of the processing shown below, counting is suspended until completion
of the processing execution.
Upon completion of the processing, the counting restarts.
However, if the same interrupt occurs again during each processing, these interrupts are counted as once.
• Each instruction on the sequence program
• Interrupt program
• Fixed scan execution type program
9 - 30
instruction.
n
Maximum counting
=
speed (Cmax)
100
*1: Duty (n) is the ON-OFF time ratio of count input signal, and is expressed as a percentage
value.
T2
T2, n =
100%
T1+T2
T1
100%
T1+T2
ON
OFF
Figure 9.35 Duty ratio
)(
OUT
OUT
END
C
C
Figure 9.36 Ladder example for increasing the maximum counting speed
n: Duty (%)
1
[times/s]
T:
Execution interval of the OUT C
T
T1
T2
Section 3.8.2) for the counter input signal.
OUT
OUT
END
C
C
*1
instruction (sec)
OUT
C
Execution interval of the
OUT C
instruction
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