Note
Changing the calibration
can cause profound changes in flowmeter operating characteristics.
Use only the most respected flow standard to obtain a correction factor. The percentage
entered must provide an accurate and consistent shift across the entire flow range anticipated
for the application.
Kc Factor
To obtain the Kc factor, compare flow total data taken simultaneously from the flowmeter and
a reference meter whose accuracy meets the required standard. Allow both meters to
accumulate flow total data long enough to average out any differences due to flow fluctuation
between the two meter locations. Compare outputs of the two totalizers to determine
percentage increase (+) or decrease (-) that is necessary to produce the best average
correlation between the flowmeter and the reference standard.
Selecting the Kc Factor
When the [Kc] menu cell is selected, the flowmeter imposes this percentage slope adjustment
of its rate output. Output data is zeroed and corrected for the Reynolds number (flow profile
compensated), however, a percent change in the rate output is imposed based on the data
entered in this cell. The number entered by the user is evaluated into a slope correction factor
by dividing it by 100 and algebraically adding it to 1. The resulting factor is used as a multiplier
on the rate register of the instrument. Thus an entry of -3% will multiply the rate register by
0.97, for example.
To calculate Kc:
To enter the Kc Factor
1. To enable numeric entry press <Right>.
2. Use
the numeric keys to type the required Kc (as calculated above). Note that the Kc value
can be negative or positive. Enter the - or + sign first, then type in the calibrated value.
3. To store the data press <ENT>. Note that Kc now appears in the right-hand column of the
[Calibrate Flow Rate] menu cell with its new value. Also note that this Kc value can be
viewed on the site printout.
Calibration Tables 1 through 3
SITRANS F 1010 instruments offer a unique methodology by which a particular flow response
of an instrument may be linearized or optimized by tabulating the results of a series of
calibration exercises or collected batch data points. Basically, the flowmeter allows the user
to select any of a wide variety of system variables (flowrate, pressure, viscosity, etc.) as a
pointer into a table of calibration factors (up to 32). As the system variable is updated, the value
of the table’s output factors (or positive and negative flow) is re-evaluated and used as a
Appendix
A.5 Flowrate Calibration and Calibration Tables
FUP1010 IP67 Portable Flowmeter
146
Operating Instructions, 02/2010, A5E02951522A Revision 01
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