Xylem Flow Converter 713 - Manual (Page 8)

8
Mounting of sensor
Ultrasonic measuring system
The Ultrasonic sensor must be placed correctly according to the actual
measuring stormflows. The sensor has to be installed at right angles
above the liquid surface (level tube). We recommend using bracket
type MJK 0070, and if necessary it can be used together with univer-
sal brackets of type MJK 0005.
The following distances ensure a correct function:
Hydrostatisc measuring system
The pressure transmitter must be placed correctly according to actual
measuring stormflows. The sensor must be fasted possibly mounted
on a pipe with a 1 inch. internal screw thread. In some case it might be
necessary to mount the pressure transmitter in a measuring well, so the
transmitter will not effect current of water.
The following distances ensures a correct function:
Flow Converter 713
4-20 mA supplied
4-20 mA output signal
Level Transmitter 511U
Supply
An example of an installation, with long distance
(more than 50 m) between the measuring location
and the amplifier. A MJK 511 Level transmitter (with
a 3-wire, 4-20 mA supply) is applied as preamplifier,
and the signal is transmitted via an ordinary 3-wire
cable. The 511 level transmitteren is set for 100%
measuring range, this allows any adjusting of the
measuring range to be carried out from the flowcon-
verter. This mounting allows you to have a distan-ce
between sensor and amplifier of more than 1000 m.
Electrical connection of the Flow Converter 713, for hydrostatical, and ultrasonic measurement systems respectively.
Supply
Hydrostatic sensor 7062
Supply
Ultrasonic sensor 7005
+ -
Relais 1 to 4 Puls output Analog
output
Flow Converter 713
Hydrostatic measuring
system
Flow Converter 713
Ultrasonic measuring
system
Electrical connection
When measuring stormflows, it might be necessary to mount a reflec-
tion plate, within the measuring range, to ensure that the echo signals
are returned. E.g. if the distance at low levels exceeds the maximal
sensor height.
The distance from the reflection plane to the 0-level of the measuring (=
normally the height of the weir) is set as the 0-level suppression. Notice
that the 0-level suppression must be added to the measuring range, to
respect the maximal sensor height
The following always applies to ultrasonic measuring systems:
Maximal sensor height = blockingdistance + measuring range +
optional 0-level suppression
The following always applies to hydrostatic measuring systems:
Maximal sensor height = measuring range + optional 0-level sup-
pression
Notice that the 0-level suppression must be added to the measuring
range. 0-level suppression
Measuring range
Measuring range
Recommended at flow- and
stormflow measurings
Without 0-level suppres-
sion - recommended at
normal flow measuring in
flumes and weirs
Blocking
distance
Sensor height
Measur-
ing-
range
With 0-level suppression -
recommended at stormflow
measurings
Sensor height
Blocking
distance
0-level
suppression
Measur-
ing
range
Opt. reflection plate
Measuring range 0-30 cm 0-1 m 0-3 m
Blocking distance 40 cm 40 cm 75 cm
Min. meas. range 10 cm 10 cm 30 cm
Max. meas. range 30 cm 1 m 3 m
Max. sensor height 70 cm 140 cm 3,75 m
Measuring range 0-30 cm 0-1 m 0-3 m
Min. range 10 cm 30 cm 1 m
Max. range 30 cm 100 cm 3 m