Ultraflux UF 831, Руководство пользователя, Страница: 37 / 109

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NT UF 831 CO GB (b) / March 2014
5.4.4 "Level settings" menu
This menu is dedicated to setting the level measurement.
The level measurement is essential for measuring the flow. In fact, ultrasonic probes are used to measure
the average flow velocity of the fluid in the channel and the level is used to find out the surface wetted by
the fluid in the section of the channel.
1) Number of level measurements
UF 831 can be used to manage up to four level measurements.
The menu below is used to select by level the input channel which corresponds to the level measurement
(for example, a 4-20mA input):
The measurement used to calculate the flow (priority measurement) is level 1. If this is faulty, the flow
meter automatically switches to level 2 (and so on, potentially up until level 4). The red fault LED is then lit
and the flow meter generates a Level 1 fault.
Note: To measure a level, a simple solution involves using a current input. The flow meter will deduce the
level of water in which the sensor is immerged from the current measured. Simply configure the range of
the sensor and the base of its scale. For further information on the configuration of the inputs/outputs, see
the chapter dedicated to this subject.
Comment: For a level sensor taking a downward measurement (for example, a measurement by ultrasound
in the air), the range of the measurement entered in the flow meter must be negative.
5.4.5 "Hydraulic profile settings" menu
1) Description of the hydraulic profile
The vertical hydraulic profile is described using 20 sections.
Each section is defined by its lower and upper elevations and by its hydraulic coefficient (see this concept in
our didactic handbook "Ultrasonic transit time flowmeter").
The value of this coefficient may be fixed section by section (absolute mode) or may be calculated for each
section based on the distance from the section to the surface.