Aalborg TIO Totalizer I/O Flow Monitor/Controller - Manual (Page 44)

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5.3.15 Submenu “Signal Conditioner”
A noise reduction filter algorithm (Running Average or Noise Reduction Filter) is
available in the flow meter when pulsating flow or especially noisy signals are
encountered. The Flow Linearizer algorithm is also available when flow linearity
must be improved.
There are three parameters which make up Running Average Filter:
• Number of Samples
• Time Interval
• Error Limit
They are described individually below.
The following settings are available for the “Signal Conditioner” (see Figure 5.7):
a) Signal Conditioner Mode (Tabular Entry)
This option determines whether the Noise Reduction feature is enabled
and the type of noise reduction algorithm. The following selections are
available:
• Disabled
• NRF (Noise Reduction Filter)
• Running Average
Factory default value is NRF.
b) NRF Number of Samples (Numerical Entry)
The sample number value between 1 and 32 can be selected. The
number of samples value represents the number of previous individual
inputs used to calculate the average value. Eventually the number of
samples in the running average also affects the response time. The
more samples are used, the more inertial flow output readings will be to
the actual flow change. A suggested nominal number of 12 samples
(default value) is a good starting point for most applications.
c) NRF Time Interval (Numerical Entry)
Time Interval can be selected between 0 and 199 ms. The value
represents the response time of the NRF flow rate change. The higher
the Time Interval values the longer the response time of the filter. If
noise reduction filter is not desired, it may be disabled by setting the
Time Interval parameter to zero. By default units are shipped from the
factory with the Time Interval value set to 50.