Setting Up Linearization; Understanding Linearization - ABB LWT300 series User Manual

Reaction
You can configure the instrument reaction when echoes are lost for the set period of time: hold the last
value measured, hold a constant value, raise an alarm or ramp up results from the last measured value.
To do so:
1 Select Device Setup > Safety Setting > Echo Lost Reaction.
2 Press Edit.
3 Highlight the necessary reaction and press OK.
Value
This is the value to hold if you select Constant Value from the Echo Lost Reaction menu.
To set the constant value to hold:
1 Select Device Setup > Safety Setting > Echo Lost Value.
2 Press Edit.
3 Set the value for lost echoes and press OK.
Ramp
You can set an expected rate (in %/min) at which the vessel should fill up (or drain if the %/min is
negative) even once echoes are lost. This value applies when you select Ramp Value from the Lost Echo
Reaction menu.
To set the ramp-up rate to apply when echoes are lost:
1 Select Device Setup > Safety Setting > Echo Lost Ramp.
2 Press Edit.
3 Set the ramp-up value in percentage per minute (%/min) and press OK.
NOTICE
The ramp-up value can be negative if you expect the level to go down.

Setting up linearization

In your LWT instrument, the linearization function allows more accurate volume measurements by
referring to a preset linearization table.

Understanding linearization

Linearization is especially useful in irregularly shaped vessels (cylindrical lying tanks, spherical gas
tanks, etc.), but in all applications, regardless of vessel shape, it is used to convert level to volume or
flow.
The linearization table provides the instrument with data regarding known volumes at specific levels in
the irregularly shaped part of a vessel.
Below is an example of the relationship between a linearization table actual measured levels:
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User Guide