8
5 Function
5.1 Measuring principle
Fig. 5-1
Fig. 5-2
The unit operates on the principle of guided wave radar� It measures the level
using electromagnetic pulses in the nanosecond range�
The pulses are transmitted by the sensor head and guided along the probe
(Fig� 5-1)� When they hit the medium to be detected they are reflected and guided
back to the sensor (Fig� 5-2)� The time between transmitting and receiving the
pulse directly relates to the travelled distance (D) and the current level� The
reference for distance measurement is the lower edge of the process connection�
By using a coaxial probe, the guided wave runs only along the inside of
the coaxial pipe� This allows installation where space is very restricted
5.2 Features of the unit
5.2.1 Easy set-up
• When operating voltage is applied to the unit for the first time, the probe length
and the medium to be detected must be entered� Then the unit is ready for
operation
• If necessary, parameters for the output signals and optimisation of the
monitoring functions can be set (
to
)�
• All settings can also be carried out before installation of the unit�
• Reset to the factory settings is possible�
