Measurement Range; Near Range; Far Range; Measurement Response - Siemens Sitrans LR250 Instruction Manual

Measurement Range

Near Range

Near Range (2.2.3.5. 1 .) programs SITRANS LR250 to ignore the zone in front of the
antenna. The default blanking distance is 50 mm (1.97") from end of horn antenna.
Near Range allows you to increase the blanking value from its factory default. But Auto
False Echo Suppression (2.2.4.2.) is generally recommended in preference to extending
the blanking distance from factory values.

Far Range

Far Range (2.2.3.5.2.) can be used in applications where the base of the vessel is conical
or parabolic. A reliable echo may be available below the vessel empty distance, due to an
indirect reflection path.
Increasing the Far Range to 30% or 40% can provide stable empty vessel readings.

Measurement Response

Note: Sensor units are in meters by default.
Response Rate (2.2.6.1.) limits the maximum rate at which the display and output respond
to changes in the measurement. There are three preset options: slow, medium, and fast.
Once the real process fill/empty rate (m/s by default) is established, a response rate can
be selected that is slightly higher than the application rate. Response Rate automatically
adjusts the filters that affect the output response rate
Response Rate (2.2.6.1.)
* Slow
0.1 m/min (0.32 ft/min)
Medium
1.0 m/min (3.28 ft/min)
Fast
10.0 m/min (32.8 ft/min) 10.0 m/min (32.8 ft/min)
Page 116 SITRANS LR250 (PROFIBUS PA) – INSTRUCTION MANUAL
Fill Rate (2.2.6.2.)/
Empty rate (2.2.6.3.)
0.1 m/min (0.32 ft/min)
1.0 m/min (3.28 ft/min)
Filter
LOE
Time
Timer
Constant
(2.4.1.)
(2.3.1.4.)
10 s 100 min
10 s 10 min
0 s 1 min
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