Siemens SITRANS FC330, Руководство по эксплуатации, Страница: 272 / 280

The offset value must be within the determined " Offset limit" (menu item number 2.1.3.6).
Note
Exceeded zero point offset limit
If the offset value is greater than the configured limit, proceed as follows:
● Check that the tube is completely filled and that the flowrate is absolute zero.
● Check the validity of the configured zero point offset limit.
● Repeat the zero point adjustment.
Zero point standard deviation
After completion of the procedure, the standard deviation is calculated in accordance with the
following formula:
Zero Point Standard Deviation
Standard deviation of N values
1 1
) (
1
2
2
1
2
−
+ −
=
−
−
≡
∑ ∑
= =
N
x x N
N
x x
s
N
i
i
N
i
i
The standard deviation contains important feedback on the homogeneity of the fluid, for
example on the presence of bubbles or particles.
The standard deviation must be within the determined "Standard deviation limit" (menu item
number 2.1.3.4).
Note
Exceeded standard deviation limit
If the standard deviation is greater than the configured limit, proceed as follows:
● Check that the tube is completely filled and that the flow rate is absolute zero.
● Check that the installation is vibration-free.
● Check the validity of the configured standard deviation limit in parameter 2.1.3.4 "Standard
deviation limit".
● Repeat the zero point adjustment.
Successful automatic zero point adjustment
If the new zero point offset value is valid, it is automatically stored as the new zero point for the
sensor. It remains stored in case of a power failure.
Zero point adjustment
SITRANS FC330
272
Operating Instructions, 01/2019, A5E44030648-AB