Programming
Page 33
May 2020
DSY-PM-01378-EN-08
Coefficient
The coefficient is the value applied to the nominal K-factor to correct it to the exact K-factor
for that point� The coefficient is calculated by dividing the average (nominal) K-factor for
that point by the actual K-factor for the flow meter�
Linear Coefficient =
Actual K-Factor
Nominal K-Factor
At the
Coef#1
prompt, press
ENTER
� The first digit of the coefficient flashes� Press
UP
to increment the digit, and
RIGHT
to move to the next digit� When all digits have been
entered, press
ENTER
to advance to the next frequency input�
Continue entering pairs of frequency and coefficient points until all data has been entered�
Press
ENTER
to advance to the Modbus parameter�
OTE:
N
The frequency values must be entered in ascending order� If a lower frequency
value is entered after a higher value, the B2900 monitor flashes
Limit
followed by
the minimum frequency value acceptable to the display�
Example:
The following is actual data taken from a one inch turbine flow sensor calibrated with water�
Unit Under Test (UUT) Calibration Data Table In GPM
Actual
UUT
Frequency
UUT Actual
K-factor
(Hz x 60)
Nominal K
Linear
Coefficient
Raw Error
50�02 gpm
755�900 Hz
906�72 counts/ US gal
49�72 gpm
1�0060
0�59%
28�12 gpm
426�000 Hz
908�96 counts/ US gal
28�02 gpm
1�0035
0�35%
15�80 gpm
240�500 Hz
913�29 counts/ US gal
15�82 gpm
0�9987
–0�13%
8�88 gpm
135�800 Hz
917�57 counts/ US gal
8�93 gpm
0�9941
–0�59%
4�95 gpm
75�100 Hz
910�30 counts/ US gal
4�94 gpm
1�0020
0�20%
Nominal K (NK)
912�144
—
—
Table 1: Sample linearization data
In this example, the linear coefficient has already been calculated by the calibration
program so all that is required is to enter 5 into the number of linear points
Lin Pts
parameter and then enter, in order, the five frequency, linear coefficient data pairs�
Modbus
The Modbus output parameter can be enabled or disabled� When enabled,
communications with the B2900 monitor are completed using the Modbus RTU protocol�
See
for additional information�
At the
Modbus
prompt, press
ENTER
� The current state of the Modbus output is shown�
If the current state is correct, press
ENTER
to advance to the next parameter� To change
the modbus setting, press
UP
or
RIGHT
to toggle between states� When the proper state
displays, press
ENTER
to advance to the
BusAddr
parameter�
