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Setting up a volume table
– (EView2 Linearization curve (VMT) – VMT (HART
®
Fct 2.1.7)
To be able to measure the volume, a conversion table (strapping table) will need to be created using the EView2 program or the HART
®
communicator.
The strapping table assigns defined volumes to the various levels. In the case of non-symmetrical tanks, e.g. tanks with dished bottom, the accuracy of volumetric
measurement will depend on the number of entered “level/volume pairs”. The maximum number of pairs (points) that can be set is 20. The volume is linearly determined
(interpolated) between 2 points. The conversion table is generally used for volume, but can also be used for mass and flow.
Five points have been set in the following example.
Example procedure 3:
creating a strap table by assigning a volume to a user-defined level (using EView2)
Step
Action
Data entered/value selected
1
Open the “DEVICE SETTINGS” window of the device in EView2
2
Select the “Application” tab and chose the “Calculation system”
Metric (EU), Imperial (US), Optional
Unit
3
Select “Length Unit” in the “Application” tab
m or ft
4
Go to „Volume Unit” to select volume units
m³ or ft³
5
Select „Measurement configuration” tab.
6
Go to user function “Tank height” to enter tank height value (click on field and type in value)
6.00 m (20 ft)
7
Go to user function „Probe length” to enter probe length value
5.80 m (19 ft)
8
Go to user function „Dead zone” to enter dead zone value
0.40 m (1.3 ft)
9
Press “Send” button in the bottom right corner for the MicroTREK to accept the new value.
Wait for the download process to
complete
10
Select the „Linearization curve” tab.
Fill in the table “VMT list” with the appropriate values.
A maximum of 20 points can be entered. For each point a level and a volume must be entered.
Each point should have a value higher than the preceding one.
You can create a new line by pressing the Ctrl + Insert keys, or by selecting "Add new item" from the local menu.
You can delete a line by pressing Ctrl + D keys together.
See table below
(table
Table 2. )
11
To download the table to your device, press “Send” button under the „Get” button on this tab („Linearization curve”
tab).