Fluidwell E119-P User Manual

E119-P
Page 30 FW_E119-P_M_v0301-02_EN
4 FLOWMETER
4.4 K-FACTOR
Converts the flowmeter pulse signals to a quantity. The K-factor is based on
the number of pulses generated by the flowmeter per measurement unit
selected in 4.3: FLOWMETER > UNIT.
The more accurate the K-factor, the more accurate the system.
After pressing PROG, the decimal point will start to flash. The decimal
position can then be changed by pressing the SELECT-key, then press the
CLEAR key to set the digits.
5.5.5 MENU 5: LINEARIZATION
Linearization principle
In normal situations, the calculation of flow is based on flowmeters that follow an ‘ideal line’ and give
a fixed number of pulses over the entire frequency range to represent a certain amount. The
calculation uses an average K-factor KF0, which corresponds to the factors entered at
SETUP
4.4: FLOWMETER > K-FACTOR when automatic K-Factor conversion is enabled, or
SETUP
1.3: TOTAL > K-
FACTOR and 2.4: FLOWRATE > K-FACTOR when automatic K-Factor conversion is disabled.
Since many flowmeters do not follow this ‘ideal line’, the linearization function can be used to reflect
the actual flow curve better. This allows for more accurate flowrate and totalization values, as well as
improved analog and pulse output values over the frequency range of the flowmeter. The
linearization function uses linearization points to calculate new K-factors based on the measured
flowmeter frequency. As shown in the chart below, each point consists of a frequency and a Meter
Factor (MFx, indicating the deviation of the K-factor KFx from the average K-factor KF0).
KF0
KF0
64 93 161 336 514 10,000
Frequency
Hz
K-Factor
KF0=51.64178
KF1=35.7 @ 64Hz.
KF2=47.5 @ 93Hz.
KF3=53.8 @ 161Hz.
KF4=49.2 @ 336Hz.
KF5=52.9 @ 514Hz.
KF1
KF2
KF3
KF4
KF5
MF1=0.691300
MF2=0.919798
MF3=1.041792
MF4=0.952717
MF5=1.024364
0
0
35.7
51.6
Fig.17: Example of K-Factors and linearization points
When a new frequency is measured, the corresponding Meter Factor is calculated by interpolating
between the linearization points. The new Meter Factor is then used to calculate the actual K-factors
for flowrate and total using this formula:
When the measured frequency is below the lowest or above the highest frequency given in the
linearization points, the Meter Factor belonging to that frequency is used.

Fluidwell E119-P Specifications

General

Brand	Fluidwell
Model	E119-P
Category	Measuring Instruments
Language	English