69
6.12
Density Calibration Adjustment
6.12.1 Water as the reference liquid:
It is often convenient to do a field calibration of the density function using water as the
reference liquid. Fill the flowmeter with water which is free of air. It is best to be operating the
system at process flow rates and at a stable temperature. The calibration will automatically
input the operating frequency, temperature and the density of water at the temperature
according to the reference table on the following pages. Note the metric units for the
reference tables are Kg/m
3
. To convert to g/cm
3
divide by 1000.
Follow the key strokes in the diagram below to accomplish this calibration. Begin from the
measuring mode:
Key
Display
line 1
line 2
Step #
→
Fct.(1).0
OPERATOR
1. Enter programming mode
2x
↑
Fct.(3).0
INSTALL
2.
→
Fct.3,(1).0
BASIS.PARAM
3.
8x
↑
Fct.3.(9).0
TUBE PARAMS
4.
→
Fct.3.9.(1)
CF1 Fgw
5.
9x
↑
Fct.3.9.(10)
D.REF.WATER
6.
→
(MEAS.VALUE)
7.
↵
CALIB. (NO)
8.
↑
CALIB. (YES)
9.
↵
Fct.3.9.(10)
D.REF.WATER
10.
4x
↵
11. Return to measuring mode
6.12.2 Process fluid as the reference fluid:
Often it is very convenient to use the actual process fluid to calibrate the density output under
actual operating conditions against the in-plant density reference. Be certain the process is
running in a stable fashion at or near normal operating conditions. To perform this calibration,
proceed with key strokes as in 6.12.1 above except after having reached step 10, proceed as
follows:
Key
Display
line 1
line 2
Step #
→
(MEAS. VALUE)
11.
↑
(SET VALUE)
12.
↵
+132.3566
FREQUENCY
13. set automatically in step 9: do not adjust.
↵
+ 67.5
(
°
C)
14. set automatically in step 9: do not adjust.
↵
0.9990
(g)/cm
3
15. set mass units
→
0.9990
g/(cm
3
)
16. set volume units
→
(0)0.9990
g/cm
3
17. adjust to process density value -
ex. 0.9794 g/cm
3
*
as req’d
0.9794
g/cm
3
18. density which will be the output when
measuring.
5x
↵
19. return to the measuring mode.
After returning to the measurement mode, the density should read 0.9794 g/cm
3
if the above procedure was
carried out correctly and the process is stable.
* If insufficient number of digits appear to permit adequate resolution refer to Section 6.5 which explains how to
increase the number of digits.
