8
Function
5
Measuring principle
5.1
The unit operates to the principle of
guided wave radar� It measures the
level using electromagnetic pulses in
the nanosecond range�
The pulses are transmitted by the sen-
sor head and guided along the rod (fig�
1)� When they hit the medium to be
detected they are reflected and guided
back to the sensor (fig� 2)� The time
between transmitting and receiving the
pulse directly relates to the travelled
distance (D) and the current level�
The reference for distance measure-
ment is the lower edge of the process
connection�
D
2
1
The figure shows operation with single
probe�
In case of operation with a coaxial probe,
the guided wave runs along the inside of
the coaxial pipe�
Features of the unit
5.2
Easy set-up
When the unit is supplied with operating voltage for the first time, the probe
•
length, the medium to be detected and the type of probe used must be entered�
After this, the unit is operational. (→ 10.2).
If necessary, parameters for the output signals and optimisation of the monitor-
•
ing functions can be set (→ 10.3 to 10.5).
All settings can also be carried out before installation of the unit�
•
Reset to the factory settings is possible�
•
Electronic lock can be set to prevent unintentional operations�
•
Display functions
The unit displays the current level, either in cm, inch or in percent of the final
•
value of the measuring range� Factory setting: cm� The display unit is defined
by programming (→ 10.3). In the Run mode, it can be temporarily switched
between length indication (cm / inch) and percentage:
Press [Set] briefly�
►
The selected unit is displayed for 15 s, the corresponding LED is lit�
>
With each push of the button the display type is changed�
