3.4 Setting Configuration 2 – Input Channel Settings
55
3
3
Chapter 3 Setting before Measurement
Revolution Measurement Theory
Pulse count is measured using the Memory HiLogger’s
internal 10 ms sampling interval.
The revolution rate (r) per second during time t
s
is obtained
by dividing the number of pulses from (t-1) to
t
s
by the num-
ber of pulses per revolution.
Example: Pulses per revolution = 4
When the number of pulses counted in one second is
P
100
= 1000 c,
and the number of pulses counted in two seconds is P
200
= 2000 c,
then the revolution rate (rps) at t=2
s (r
t=2
) can be obtained.
When time t
s
is less than one second
The pulse count at (t –1)
s
(whole seconds) cannot measured, so 100 times the pulse count
between (t -0.01)
s
and t
s
serves and the pulse count for one second to obtain the revolution
rate.
As a result, revolution measurements when t is less tha
n one
second are scattered.
0 10 ms 20 ms 1 s 2 s
Pulse Count
P200P100P2P10
Pulses per revolution
Pulse count at t
s
minus pulse count at (t -1)
s
r [rps] =
(rps: Revolutions per second)
r
t=2
=
4
2000 1000
= 250 [rps]
Pulses per revolution
Pulse count at t
s
minus pulse count at (t -0.01)
s
r [rps] = x 100
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