Siemens SITRANS FC410 Operating Instructions Manual page 144

Zero point adjustment
Zero point calculation
During zero point adjustment, an average value is automatically calculated using the
following formula:
Zero Point Offset Value
Average of N flow values
The offset value must be within the determined Zero Point Offset Limit (Modbus address
2140).
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
The standard deviation contains important feedback on the homogeneity of the fluid, for
example on the presence of bubbles or particles.
142
x is an instantaneous flow value sampled in
i
the time domain
N = Number of samples during zero point
adjustment
Operating Instructions, 02/2016, A5E33120874-AC
FC410 with Modbus