User's Manual

Page 120 SITRANS LR560 (PROFIBUS PA) – OPERATING INSTRUCTIONS 7ML19985LT01
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D: Technical Reference
Measurement Range
Near Range (2.4.1.)
Near Range programs SITRANS LR560 to ignore the zone in front of the antenna. The
default blanking distance is 27.8 cm (0.91 ft) from the sensor reference point.
Near Range allows you to increase the blanking value from its factory default. But Auto
False Echo Suppression (2.4.8.1.) is generally recommended in preference to extending
the blanking distance from factory values.
Far Range (2.4.2.)
Far Range allows the echo processing to see and process signals that are lower than the
Low Calibration setting.
Potential uses are:
• 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 Far Range to 30% or 40% can provide stable empty vessel readings.
• Where Low Calibration setting is above vessel empty level, but the vessel is emptied
occasionally. In this case the echo will be tracked below the Low Calibration setting
and the device will maintain a zero level reading.
Measurement Response
Response Rate (2.3.6.1.) 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/min 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
Note: Units are defined in Unit (2.3.1.) and are in meters by default.
Response Rate
(2.3.6.1.)
Fill Rate/Min (2.3.6.2.)/Empty
rate/Min (2.3.6.3.)
Filter Time Constant
(2.5.8.1.)
Slow
0.1 m/min (0.32 ft/min) 10 s
* Medium
1.0 m/min (3.28 ft/min) 10 s
Fast
10.0 m/min (32.8 ft/min) 0 s