Endress+Hauser Proline Promass 80 - Density adjustment; Performing a density adjustment

6 Commissioning PROline Promass 80
54 Endress+Hauser
6.2.4 Density adjustment
Measuring accuracy in determining fluid density has a direct effect on calculating
volume flow. Density adjustment, therefore, 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.
Performing a density adjustment
"
Caution:
• On-site density adjustment can be performed only if the user has very 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.
• A density adjustment changes the factory density calibration values or the calibration
values set by the service technician.
The functions outlined in the instructions below 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
equalised. The time you have to wait for equalisation depends on the fluid and the
temperature level.
3. Select the density adjustment function:
HOME
→ F → R → PROCESSPARAMETER → N → DENSITY SET VALUE
– When you press OS
you are automatically prompted to enter the code if the
function matrix is still disabled. Enter the code.
–Use OS
to enter the fluid's target density and press F to save this value (input
range = actual density value ±10%).
4. Press F and select the “MEASURE FLUID” function.
Use OS
to select “START” and press F . Then, the message “DENSITY ADJUST
RUNNING” appears for approx. 10 seconds on the display. During this time
Promass measures the current density of the fluid (measured density value).
5. Press F and select the “DENSITY ADJUST” function.
Use OS to select “DENSITY ADJUST” and press F . Promass compares the
measured density value with the specified value and calculates the new density
coefficient.
" Caution:
If a density adjustment does not complete correctly, you can select the “RESTORE
ORIGINAL” function to reactivate the default density coefficient.
6. Use
X to return to the HOME position (press +/– simultaneously).