Omron K35-2, Руководство пользователя

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Appendices
Appendices
A-30
Forecasted Cycle Calculations
When the input pulse stops suddenly, forecasted cycle calculations are
used to wait for the next input pulse based on frequency forecasts.
During forecasted cycle calculations, the frequency is forecasted
continuously for any point in time regardless of when the next input
pulse is received. This increases the response characteristic in the
shaded portion of the diagram.
Forecasted Cycle Calculation
(1) Frequency calculation is not possible with only pulse P
0
, so the
calculated value remains at 0.
(2) When pulse P
1
is received, the time T
1
, from P
0
to P
1
is the cycle,
so the frequency can be calculated as 1/T
1
.
(3) If pulse P
2
is received and T
1
> T
2
, the cycle has shortened (i.e.,
the frequency has increased), so 1/T
2
is used as the frequency at
that point.
(4) If time T
2
expires before the next pulse is received after receiving
pulse P
2
, it is clear that the frequency will be lower than 1/T
2
, but
the value will not be know until the next pulse is actually received.
(5) If time T
2
expires and the next pulse still has not been received
after receiving pulse P
2
, the frequency is forecasted continuously
for any point in time. The forecasted value if time T
3
has expired
from receiving pulse P
2
is 1/T
3
. If P
3
is actually received at that
time, the frequency will be 1/T
3
, i.e., the frequency at that time has
been forecasted accurately.
(6) The response characteristic for rapid changes in the input
frequency is thus improved, in comparison to assuming that the
frequency is 1/T
2
until pulse P
3
is received.
F
requency
Forecasted cycle calculation
Time
Input pulse
Frequency
T
1
P
0
P
1
P
2
P
3
T
2
T
3
T
2
1/T
2
1/T
3
1/T
1
0
Forecasted
cycle calculation