Setting Parameters
page 93
NF 650 - rev. 01 / 29.06.2020
Select from the following level sensors:
•
2-wire level
The level is measured by using an external 2-wire sensor supplied by the transmitter.
The use of 0/4…20 mA signal from external transmitters such as NivuMaster or Mul-
ti-Ranger can be enabled in this menu as well.
•
2-wire level (2)
The level is measured by using an external 2-wire sensor supplied by the transmitter.
•
i-Series sensor
Connection of NIVUS i-Series ultrasonic sensors on analog input AI1.
•
Air-ultrasonic NIVUS
The level is measured from the top down using an air-ultrasonic sensor.
•
Water-ultrasonic sensor 1
The level is measured from the bottom up using a water ultrasonic sensor.
•
Water-ultrasonic sensor 2
The level is measured from the bottom up using a water ultrasonic sensor.
•
Modbus
Connection of an external level sensor.
•
Fixed (value)
This option is conceived for permanently full pipes and channels. Such applications
do not require level measurements. The measurement system in this case provides
the constant filling level required for flow calculation.
This parameter can be used as supporting value for tests or for initial start-ups if level
values are not available.
Use of two level sensors with overlap
Choose this option if the level sensor is expected to be overflown as described in the following
example using a pipe measuring section with dome top.
Range 1
is a 2-wire pressure probe on the canal bottom with a measurement range of 0...1 m.
This pressure transducer is specified as “2-wire level (2)”.
The pressure sensor shall measure the range from 0 to max. 0.35 m. The range on top is
covered by a second sensor.
Range 2
is an i-Series sensor (installed above the water surface above the canal). This trans-
ducer shall measure as from a level of 0.32 m and is to cover up the range up to full filling.
Due to this arrangement and the according parameter settings both measurements operate
with an overlap area of 0.03 m (see also Sect. “32.3.2 Overlapped”).
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Procedure:
1. Sensor 1 (2-wire pressure probe):
Enter the level measurement range (level min. / max.), set the offset to “0.0 m”
(4 mA) and the measurement span to “1.0 m”.
2. Sensor 2 (i-Series sensor):
Enter the level measurement range (level min. / max.), select the sensor type and
enter the mounting height.
3. Verify the settings using the graph above.
32.3.2 Overlapped
This parameter is indicated/selectable only if more than one level sensor has been selected.
By including the individual measurements from a second sensor with the transmitter’s calcu-
lations it is possible to obtain “smooth transition” between the different measuring sections.
Particularly within the range of the real filling level the change to the second sensor might
possibly result in sudden jumps of measurement values.
