FP-4400 PORTABLE CLAMP-ON ULTRASONIC FLOW METER
ONICON Incorporated 727.447.6140
Page 30 onicon.com
CALIBRATION
Mode
– Read-only. Shows the selected Mode from the Units/Mode menu.
LOS Time
– Enter the LOS Time to suppress intermittent loss of signal. As an
example: systems with high concentrations of undissolved gasses will cause
fluctuations in signal strength when the gasses move past the ultrasonic signal.
If a complete loss of signal is experienced, the FP-4400 will hold the last valid
reading for the duration of the LOS Time. If the signal strength returns before the
LOS Time is expired, the meter will return to normal operation automatically. If
signal strength does not return after the LOS Time has expired, then the meter
will report zero flow on the LCD display and produce a Low Signal alarm. Default
= 10 seconds. Options = 0-99 sec.
Min Flow
– Enter the Min Flow cutoff, which means any flow rate below Min Flow
measured by the FP-4400 will result in 0 flow on the display and data log. Default
= 4 GPM (0.25 L/s) for a 4 in (100 mm) nominal pipe, which is the approximately
equal to 0.1 ft/s (0.03 m/s) flow velocity. This is the suggested flow velocity to be
used for Min Flow values in other nominal pipe sizes.
Setting the Min Flow to 0 will result in small measurements being displayed and
accumulated on the totalizer, so this should be avoided. It is possible to set the
Min Flow below a flow velocity of 0.1 ft/s, but a Zero Tare in the Setup menu may
need to be invoked to avoid false readings at zero.
Damping Mode
- Select OFF, FIR (Default), or LOW PASS. When measured
flows are outside the Window of the previous measurement, the FIR filter
will reduce the damping average so that a fast response can be made to the
sudden change in flow rate. The LOW PASS filter will ignore measured flow
rates outside the Window, while holding the previous measurement, until
there are enough measurements made outside the Window to cause a step
response to the most current measured value. While measured flows are within
the Window of the previous measurement, both the FIR and LOW PASS filter
behave the same.
Damping Percent
- Higher percentages increase the number of measurements
which are averaged together to produce a stable flow reading. Higher
percentages also increase the time it takes for the meter to make a step-
response to the measured flow rate outside the Window in the LOW PASS
Mode. Default = 10%. Options = 0-100%.
Damping Window
- Defines the Window around the running average, in
units of Velocity set in the Units/Mode menu. Measurements made inside the
Window are added to the running average, and measurements outside the
Window effect the response of the meter as described in the Mode section.
Default = 1 ft/s (0.3 m/s). Options = 0-20 ft/s (6.096 m/s).
Cal Constant
– Calibration constant defined when the FP-4400 was calibrated at
the factory. Specific to the sensor (transducer) model selected in the Setup menu.
When changing the Sensor model, a pop-up menu appears notifying the user
that this value automatically changed to the last stored value. Should this value
accidentally be changed, reference the calibration certificate included with the
FP-4400 in order to determine the factory Cal Constant.
Calibration
LOS Time
Mode
Min Flow
Damping
Mode
Cal Constant
Percent
Window
10 sec
Flow
4.00 USG/m
FIR
1.000
10%
4.1.000 ft/s