24
..... Additional setup menus within the CALIBR submenu
Manual zero set method continued
F
IGURES
3.13-D (
LEFT
) & 3.13-E (
RIGHT
)
3.13.2 Scale Factor Calibration
After setting and verifying the instrument’s zero point, you can set a scale factor to adjust the measured
flow; the measured flow is multiplied by this scale factor. For example, if the displayed flow is twice the
actual flow, you can enter a scale factor of 0.5 to divide the displayed flow by 2. The primary reason for
setting the scale factor is to compensate for manufacturing variations in the transducers. The scale factor
printed on the transducer set should be entered in Menu 52.
Observe the following precautions when setting the scale factor:
•
Always determine the scale factor at the highest possible flow rate achievable in order to maximize
accuracy of the scale factor.
•
Use only the factory preset scale factor as marked on the transducers in the following situations: the
flow cannot be stopped to verify or set the zero point; a reasonably high flow rate cannot be achieved;
an accurate secondary flow standard is not available.
If an additional scale factor is required, the additional scale factor should be multiplied by the factory scale
factor and the result should be entered. To enter a new scale factor:
1.
Access Menu 52 (Figure 3.13-F, below).
2.
Enter the new scale factor and press
ENTER
. Figure 3.13-G (below) is displayed.
3.
Enter the valid password and press
ENTER
. The new scale factor is displayed in Menu 52.
F
IGURES
3.13-F (
LEFT
) & 3.13-G (
RIGHT
)
3.13.3 Other CALIBR Submenu Options
1.
Sound Speed Compensation
setup menu (53): Enable or disable the flowmeter’s sound speed
compensation. Temperature variations in the fluid and other factors may cause variations in the fluid’s
sound speed. Typically, the flowmeter can determine sound speed more accurately when this feature
is enabled
(Figure 3.13-H, page 25)
.
