Instruction manual

Commissioning

56 Installation and Operations Manual

Caution! During the learning period, fast filling/emptying, or turbulent surfaces

can result in switching off and on the phase evaluation. Subsequently, observed

measurement errors will disappear as soon as tank levels come back to areas

measured by 7500 series RTG previously with activated phase evaluation. If the

observed measurement errors are corrected by dip table entries, the

7500 series RTG will take care of these corrections and automatically adjust the

index correction table. Do not correct any settings in the basic calibration or the

extended calibration.

Note Immediately after installation, the 7500 series RTG measures with the

specified mm-accuracy. Until the level range has been completely covered by the

medium (setting up the correction table), the maximum permissible filling speed is

100 mm level change / min. After this, the fill speed has no limitation.

Function

“

pipe diam. corr.” (032)

For level measurement in stilling wells, radar systems require highly precise pipe inner

diameter data.

An mm-exact level measurement cannot be guaranteed for deviations

from the actual stilling well inner diameter of more than ± 0.1 mm to the value entered

in the function group “basic setup” (00).

The errors which occur as a result are linear and

can be corrected with a dip table containing at least two entries. The 7500 series RTG

also has an automatic pipe inner diameter correction. This adjusts the entered stilling

well inner diameter (input in the function group “basic setup” (00)) to the actual values.

However, this presupposes that the value entered in the function group “basic setup”

(00) matches the actual pipe inner diameter as accurately as possible. The user-defined

value entered in the function group “basic setup” (00) can be corrected with this value.

Switch on the “pipe diam. corr.” (032) function, after a level change of at least 5 m has

occurred since start-up. The pipe diameter, which the device determines automatically,

will then be transmitted to the “pipe diameter” (007) function.

Note If, and only if the “pipe diameter” (007) function has changed its value, it is

necessary to perform a “history reset” (009) and to delete the dip table after

activation of the “pipe diam. corr.” (032) function. Otherwise the level change of 5 m

has not yet been exceeded. The “pipe diam. corr.” (032) function must be

deactivated again and the procedure should be repeated at a later point of time.

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