Endress+Hauser HART Proline Promass 83, Руководство по эксплуатации

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Proline Promass 83 Commissioning
Hauser 81
6.5.2 Density adjustment
It is advisable to perform a density adjustment when optimum measuring accuracy is
required for calculating density dependent values. The application may require a 1-point or
2-point density adjustment.
1-point density adjustment (with one fluid):
This type of density adjustment is necessary under the following circumstances:
• The sensor does not measure exactly the density value that the user expects on the basis
of laboratory analyses.
• The fluid properties are outside the measuring points set at the factory, or the reference
operating conditions used to calibrate the measuring device.
• The system is used exclusively to measure a fluid’s density which must be registered to a
high degree of accuracy under constant conditions.
Example: Brix density measurement for apple juice.
2-point density adjustment (with two fluids):
This type of adjustment is always to be carried out if the measuring tubes have been
mechanically altered by, e.g. material buildup, abrasion or corrosion. In such cases, the
resonant frequency of the measuring tubes has been affected by these factors and is no
longer compatible with the calibration data set at the factory. The 2-point density
adjustment takes these mechanically-based changes into account and calculates new,
adjusted calibration data.
Performing a 1-point or 2-point density adjustment
"
Caution!
• Onsite density adjustment can be performed only if the user has detailed knowledge of the
fluid density, obtained for example from detailed laboratory analyses.
• The target density value specified in this way must not deviate from the measured fluid
density by more than ±10%.
• An error in defining the target density affects all calculated density and volume functions.
• The 2-point density adjustment is only possible if both target density values are different
from each other by at least 0.2 kg/l. Otherwise the error message #731 (adjustment is not
possible) appears in the "Diag. - Act. Sys. Condition" parameter.
• Density adjustment changes the factory density calibration values or the calibration values
set by the service technician.
• The functions outlined in the following instructions are described in detail in the
"Description of Device Functions" manual.
1. Fill the sensor with fluid. Make sure that the measuring tubes are completely filled and
that liquids are free of gas bubbles.
2. Wait until the temperature difference between fluid and measuring tube has equalized.
The time you have to wait for equalization depends on the fluid and the temperature
level.
3. Using the local display, select the SETPOINT DENSITY function in the function matrix
and perform density adjustment as follows:
Function
No. Function name Setting to be selected (
O
or
S
)
(to next function with
F
)
6482 DENSITY ADJUST MODE Use
P
to select a 1- or 2-point adjustment.
!
Note!
When you press
P
you are automatically prompted to enter the
access code if the function matrix is still disabled. Enter the code.
6483 DENSITY SET VALUE 1 Use
P
to enter the target density of the first fluid and press
F
to
save this value (input range = actual density value ±10%).