Setting Process Conditions; Setting Data Filtering Parameters; Selecting A Maximum Level Rate - ABB LWT300 series User Manual

Setting process conditions

You can also set the various conditions occurring inside the tank if you want them to be taken into
consideration when the instrument is taking measurements. For this to happen, you need to enable any
of the following conditions, when relevant:
• Buildup detection (residue that might be accumulated on the probe.)
• Foaming (foam that forms on top of the measured substance.)
• Flashing (drastic changes in level inside the vessel.)
• Emulsion (if two elements with vastly differing DCs are mixed temporarily, e.g., water and oil.)
• Agitation (if levels might be affected by moving objects inside the vessel, e.g. mixing blades.)
• Changing dielectric constant (if the dielectric constant of the vessel content changes depending of
the phase of the content, e.g., liquid vs. vapor water.)
All these conditions are disabled by default. They are all enabled in a similar fashion, as explained
below:
1 Select Device Setup > Application Setup > Process Condition.
2 Highlight the relevant process condition and press Edit.
3 Highlight Enable and press OK.

Setting data filtering parameters

Processes can induce noise in level measurements. The LWT filtering feature is designed stabilize
measurements by filtering out extraneous data that could negatively impact the resolution of the
measured level (spikes, obstructions by mixer blades, lack of signal, etc.).
These parameters are set in the Filtering menu under the Device Setup menu.
—
Figure 31 The Device Setup menu
The various filters available are applied in a sequence as follows:
Max Level Rate — Median filter — Damping

Selecting a maximum level rate

The maximum level rate is the rate at which the process will reach its Full limit. This influences the
processing speed of the instrument. The default value is No Filter.
To set the maximum level rate:
1 Select Device Setup > Filtering > Max Level Rate.
2 Press Edit.
3 Highlight the appropriate maximum level rate and press OK.
47
Configuring the instrument