Endress+Hauser Proline Promass A 100 PROFINET Operating Instructions Manual page 76

Commissioning
Parameter
Execute density adjustment
Progress
Density adjustment factor
Density adjustment offset
76
Prerequisite
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Zero verification and zero adjustment
All measuring instruments are calibrated in accordance with state-of-the-art technology.
Calibration takes place under reference conditions →  137. Therefore, a zero adjustment
in the field is generally not required.
Experience shows that zero adjustment is advisable only in special cases:
• To achieve maximum measurement accuracy even with low flow rates.
• Under extreme process or operating conditions (e.g. very high process temperatures or
very high-viscosity fluids).
• For gas applications with low pressure
To achieve the highest possible measurement accuracy at low flow rates, the
installation must protect the sensor from mechanical stresses during operation.
To get a representative zero point, ensure that:
• any flow in the device is prevented during the adjustment
• the process conditions (e.g. pressure, temperature) are stable and representative
Zero verification and zero adjustment cannot be performed if the following process
conditions are present:
• Gas pockets
Ensure that the system has been sufficiently flushed with the medium. Repeat flushing
can help to eliminate gas pockets
• Thermal circulation
In the event of temperature differences (e.g. between the measuring tube inlet and
outlet section), induced flow can occur even if the valves are closed due to thermal
circulation in the device
• Leaks at the valves
If the valves are not leak-tight, flow is not sufficiently prevented when determining the
zero point
If these conditions cannot be avoided, it is advisable to keep the factory setting for the zero
point.
Description
Shows the progress of the
process.
Proline Promass A 100 PROFINET
User interface Factory setting
• Cancel –
• Busy
• Ok
• Density adjust
failure
• Measure density 1
• Measure density 2
• Calculate
• Restore original
0 to 100 % –
Signed floating-point –
number
Signed floating-point –
number
Endress+Hauser