Greyline TTFM 6.1, User Manual

Page: 18 / 79

Page 18
TTFM 6.1 Transit Time Flow Meter
CALIBRATION (cont.)
Damping
Mode
Choose between OFF, FIR (Default), or LOW PASS.
When measured flows are outside the Window of the running
average, 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 running average, until there are
enough data points outside the Window to cause a step-
response to the new measured value.
While measured flows are within the Window of the running
average, both the FIR and LOW PASS filter behave the same.
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.
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.
Cal
Constant
Calibration constant defined when the TTFM was calibrated at
the Greyline factory.
Press

to return to Menu Selections.
--Calibration-------
Mode Flow

20mA 500.00 USG/m
4mA 0.00 USG/m
LOS Time 10 sec
Min Flow 4.00 USG/m
Damping
Mode FIR
Percent 10%
Window 1.0 ft/s
Cal Constant 1.00