2
1. INTRODUCTION
Application
The Echotel compact ultrasonic level transmitters from MAGNETROL
are an excellent tool for the level measurement of liquids.
Level measurement technology based on the non-contacting ultrasonic
principle is especially suited for applications where, for any reason, no
physical contact can be established to the surface of the material to be
measured.
Such reasons may include corrosive attack by the process medium
against the measuring device material (acids), possible contamination
(sewage) or particles of the process medium adhering to the measuring
device (adhesive materials).
A Total beam angle
of 5
°
-7
°
at –3 dB as is featured by most of
Magnetrol’s transducers ensuring a reliable measurement in
narrow silos with uneven side walls as well as in process tanks
with various protruding objects. Furthermore, as a result of the
narrow beam angle - the emitted ultrasonic signals have an
outstanding focusing - deep penetration through gases, vapour
and foam is ensured.
5 m
r=22 cm
r=44 cm
r=66 cm
r=88 cm
10 m
15 m
20 m
r
5 m
r=22 cm
r=44 cm
r=66 cm
r=88 cm
10 m
15 m
20 m
rr
The Diameters
corresponding to
5° beam angle.
Principle of Operation
The ultrasonic level metering technology is based on the principle of
measuring the time required for the ultrasound pulses to make a round
trip from the sensor to the level to be measured and back. The sensor
emits an ultrasonic pulse train and receives the echoes reflected. The
intelligent electronic device processes the received signal by selecting
the echo reflected by the surface and calculates from the time of flight
the distance between the sensor and the surface which constitutes the
basis of all output signals of the Echotel
Dead Band
is a feature common to all
ultrasonic level meters. It is specified as
“Minimum measuring distance” in the
Technical Data Table.
2. Identification Code
Basic Model Number:
3
3
5
=
Integrally mounted transmitter with 50 kHz transducer and 8 meter range
3
3
8
=
Integrally mounted transmitter with 80 kHz transducer and 6 meter range
Electronics Housing:
P
=
Plastic (PBT) housing
A
=
Aluminum housing
Input power:
A
=
85 to 265 V AC
D
=
10.5 to 40 V DC,
10.5 to 28 V DC
Signal Output:
1
=
4 - 20 mA & SPDT relay
Accessories:
0
=
No digital display/programming module
A
=
Digital display/programming module included
Agency Approvals:
G
=
General purpose IP 67
Mounting:
5
=
2" NPT
B
=
2" BSP
Transducer Material:
P
=
Polypropylene
K
=
Kynar
3
3
-
-
Order Codes for Accessories
:
1.
046 – 8108 - 001 : Local Indicator for Echotel 335/ 338 series
2.
013 – 6165 - 001 : Magnetic Screwdriver - Calibration tool