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4.10.5.4
Zero point adjustment
In the following the automatic zero point adjustment function is described.
Note
Preconditions
Before a zero point adjustment is initiated, the pipe must be flushed, filled and at an absolute
flowrate of zero preferably also at operating pressure and temperature.
Note
Change of parameters during zero point adjustment
Do not change any other parameter during the zero point adjustment procedure.
Automatic zero point adjustment
The device measures and calculates the correct zero point automatically.
The automatic zero point adjustment of the flowmeter is set by the following parameters:
● Duration (Modbus address 2135)
● Start Zero Point Adjustment (Modbus address 2180)
When zero adjust is initiated by selecting Start Zero Point Adjustment, the massflow values
are acquired and totalized for the configured period (Duration). The default zero point
adjustment period (30 s.) is normally sufficient for a stable zero point measurement.
Note
Extremely low flow quantity
If the flow quantity is extremely small, extremely precise measurement is necessary. In this
case, a long zero point adjustment period can be selected for improved 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
N
x
x
N
i
i
∑
=
≡
1
x
i
is an instantaneous flow value sampled in
the time domain
N = Number of samples during zero point ad‐
justment
MODBUS commands
4.10 Modbus holding registers tables
FCT030 Modbus (From firmware 4.0)
62
Function Manual, 06/2018, A5E39931813-AB
Содержание SITRANS F Coriolis FCT030
Страница 6: ...Table of contents FCT030 Modbus From firmware 4 0 6 Function Manual 06 2018 A5E39931813 AB ...
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Страница 194: ...Definitions A 1 Definitions FCT030 Modbus From firmware 4 0 194 Function Manual 06 2018 A5E39931813 AB ...
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