Configuring The Filling Rate; Configuring The Draining Rate; Enabling Damping - ABB LLT100 Operating Instructions Manual

LLT100
Laser lever transmitter
7.4

Configuring the filling rate

NOTICE
The fill rate must be set to the process maximum filling
rate to avoid overflows. The instrument sensor smooths
out any change in level that is faster than the entered
filling rate.
The filling rate corresponds to the maximum speed at which a
vessel fills up. Its value is used to limit the maximum possible
rate of change of the level measurement reading during filling.
This feature is used in processes where heavy dust or vapor
can severely decrease the visibility of the level surface or
in which the laser beam can be temporarily obstructed (by
agitators, filling material, etc.)
WARNING
Because of the No Measurement Period feature, there
is a risk of overflow, should the actual filling rate exceed
the configured rate. In the case of hazardous products
(chemicals, etc.), this could constitute a risk to health/
life.
7.4.1 Enabling the filling rate feature
To do so:
1. From the Device Setup menu, select Filtering > Filling
Rate > Enable.
2. From the Enable menu, select whether or not you want to
enable the filter and press OK.
7.4.2 Setting the filling rate
To do so:
1. From the Device Setup menu, select Filtering > Filling
Rate > Rate.
2. From the Rate menu, edit the filling rate as necessary (see
also section 7.1) and press OK.
7.5

Configuring the draining rate

The draining rate corresponds to the maximum speed at
which a vessel drains. Its value is used to limit the maximum
possible rate of change of the level measurement reading
during drainage.
This feature is used in clear liquid processes where the bottom
of the tank is visible through the surface and in liquid processes
held in highly reflective stainless steel vessels.
NOTICE
This rate must be set to the process maximum draining
rate to avoid equipment (e.g., pumps) running on empty.
The instrument sensor smooths out any change in level
that is faster than the entered draining rate.
24 User Guide | OI-LLT100-EN Rev. D
7.5.1 Enabling the draining rate feature
To do so:
1. From the Device Setup menu, select Filtering > Draining
Rate > Enable.
2. From the Enable menu, select whether or not you want to
enable the filter and press OK.
7.5.2 Setting the draining rate
To do so:
1. From the Device Setup menu, select Filtering > Draining
Rate > Rate.
2. From the Rate menu, edit the draining rate as necessary
(see also section 7.1) and press OK.

7.6 Enabling damping

Processes can induce noise in level measurements.
The instrument damping filter is designed to smooth out
measurement noise in applications with slow dynamics
(e.g. liquid with slow waves).
The value entered corresponds to the damping time constant
(ranging from 1 s to 3600 s) applied to the measurement
returned by the median filter.
To set a damping time:
1. From the Device Setup menu, select Filtering > Damping >
Damping Time.
2. In the Damping Time menu, edit the duration and press OK.