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FLOWSIC600-XT · Operating Instructions · 8018846/1BHP/V2-1/2021-05 · © SICK Engineering GmbH
Product description
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2.2.4.1
Correction in FLOWSIC600-XT electronics
The geometric parameters of the Signal Processing Unit configured in the Signal Process
-
ing Unit reference the atmospheric conditions (20 °C, 1 bar ambient pressure). When a
higher-level process control system or Flow Computer writes the current process parame
-
ters gas pressure and gas temperature to the FLOWSIC600-XT, the FLOWSIC600-XT cor
-
rects the geometric parameters of the meter body based on the differences to the refer
-
ence conditions specified above.
If no current process values for pressure and temperature are available to the
FLOWSIC600-XT due to a failure of external sources (volume converter or pressure and
temperature transmitter), the device makes the correction based on the last known
pressure and temperature values.
The optional integrated pressure and temperature sensor can take over the function of pro
-
viding live data when no current process values are written to the device.
The device makes the correction based on the fixed values p
fix
and T
fix
when no current
process values for pressure and temperature are available for the FLOWSIC600-XT from the
integrated pressure and temperature sensor (volume converter or pressure and tempera
-
ture transmitter).
The fixed values p
fix
and T
fix
are typically configured corresponding to the test conditions
during high pressure calibration. The fixed values for pressure (pfix) and temperature (Tfix)
in the device should always be configured corresponding to the average process conditions
in the application when these deviate considerably from the tested conditions. Within the
framework of individual national approvals, an access restriction may prohibit modification
of the substitute values when the parameter locking switch is closed.
2.2.4.2
Correction outside the FLOWSIC600-XT electronics (volume converter)
Process pressure and temperature influence, among other things, the diameter of the flow
meters and ultimately affect the measurement uncertainty. This influence must be taken
into account and compensated, e.g. in accordance with the international standard
ISO 17089-1:2019 paragraph 9.1.
The FLOWSIC600-XT compensates pressure and temperature effects on the measuring
meter body geometry to obtain the exact actual flow volume (q
v,corr,a.c.
). SICK recommends
leaving meter body correction in the flow meter. The following equations are used for the
geometry correction in the flow meters.
α
T
... correction coefficient temperature, meter housing geometry
α
p
... correction coefficient pressure, meter housing geometry
∆
T
... difference between operating temperature and reference condition (20 °C) using the
internal correction of the meter.
∆
p
... difference between operating pressure and reference condition (1 bar(a)) using the
internal correction of the meter.
