Linearization Table; Linearization Table General Information; Linearization Table For Pulse Inputs; Linearization Table For Analog Inputs - Omega FC-21 User Manual

7.6 Linearization Table

Linearization
The Linearization Table is used when the flow input device gives a nonlinear
Table
input signal.
General
operator, to form a curve for linearizing the input signal.
Information
Notes:
1) A minimum of three points must be set up.
2) If "0" is entered for the frequency of any point other than point 1, the Flow
Computer assumes there are no more points above the points that preceded
them. The display will advance to the next setup prompt. Extrapolation is
taken from the last two nonzero points.
3) If the input frequency is above the highest or below the lowest frequency
programmed, the unit will use the last known point for the K factor in
computing the resulting actual flow.
4) Frequencies or apparent flows should be entered in ascending order.
Linearization
The linearization table for pulse inputs programming is quite simple when
Table
values of frequency and flow are known. The Flow Computer asks for 16
(Pulse Inputs)
different frequencies (Freq) and 16 corresponding K factors (K). It then uses
this data to determine what the actual flow is for any given input frequency.
Usually the necessary data is provided with the flowmeter.
Linearization
The Linearization Table for Analog inputs programming is similar to the Pulse
Table
input setup. The Flow Computer asks for 16 different flow rates (apparent
(Analog Inputs)
flow) and 16 corresponding Correction Factors.
determine what the Actual flow is for any given apparent input signal. Again, a
minimum of three points must be set up.
Correction factor =
The same rules that applied for the Digital setup apply for the Analog setup as
well.
The Flow Computer prompts you for the Apparent input signal (APR) and a
correction factor CFr) to multiply it by to yield true actual flow.
Linearization
The Linearization Table routine uses the entered data to determine the K
Table
factor for any given input frequency or input flow signal. This is done by taking
Interpolation
the closest data points above and below the input signal, then using those
points to extrapolate the K factor (correction factor), then calculating the
uncompensated flow from the data. Below are the formulas.
Parameters:
Determine closest point above input signal
signal = X,
Determine closest point below input signal
signal = Y,
Let input signal = H,
unknown K factor (correction factor) = KN
To find KN use this formula:
H - Y
X - Y

7.6.1 Linearization Table General Information

The unit uses up to 16 different points, as entered by the

7.6.2 Linearization Table for Pulse Inputs

7.6.3 Linearization Table for Analog Inputs

7.6.4 Linearization Table Interpolation

K factor (correction factor) = KA
K factor (correction factor) = KB
x (KA - KB) + KB = KN
Actual Flow
Apparent Input Flow
43
FC-21 Flow Computer
It then uses this data to
KA
KN
KB
Y H X
Input