UniData Communication Systems 6526 User manual

Manual
Starflow Ultrasonic Doppler
Instrument
Model 6526
This equipment has been tested and found to comply with the limits for a Class A digital device,
pursuant to Part 15 of the FCC Rules in the U.S.A. These limits are designed to provide
reasonable protection against harmful interference when the equipment is operated in a
commercial environment. This equipment generates, uses, and can radiate radio frequency
energy and, if not installed and used in accordance with the instruction manual, may cause
harmful interference to radio communications. Operation of this equipment in a residential area
is likely to cause harmful interference in which case the user will be required to correct the
interference at his own expense.
This equipment has been tested for compliance with European regulations as follows:
Application of Council Directive:
2004/108/EC
Standards to which Conformity is declared:
EN-61000-6-1:2001
EN-61000-4-2:1995
EN-61000-4-3:1995
EN-61000-4-4:1995
EN-61000-4-6:1996
ENV-50204:1995
Any changes or modifications to this equipment not expressly approved by the manufacturer
Unidata Pty Ltd could void the user’s authority to operate this equipment.
Streamline Measurement Ltd
Streamline Measurement Ltd
Streamline Measurement Ltd, 01457-864334, [e-mail], www.streamlinemeasurement.co.uk

Revision History
File name / Revision Date Authors & Change Details
Checked/
Approved
Previous version BX
2004
RS/ JH
Unidata Manual - 6526 Starflow User Manual Issue 2.0
2007
AB/CB/JH/MS/KC
Unidata Manual - 6526 Starflow User Manual Issue 3.0
2008
AB/CB
Unidata Manual - 6526 Starflow User Manual Issue 3.1.doc
2008
DM
Unidata Manual - 6526 Starflow User Manual Issue 4.0.docx - Reformat
12 09 13
MP
Unidata Manual - 6526 Starflow User Manual Issue 4.0-ines.docx
30 01 15
IM,CB
CB
Unidata Manual - 6526J Starflow User Manual Issue 5.0.docx
04 01 16
IM,PD
CB
Unidata Manual - 6526 Starflow User Manual Issue 17 01 2020.docx
17 01 20
DM (Update 3.1)
MS
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reproduced, transmitted, transcribed, stored in a retrieval system, or translated into any spoken
or computer language, in any form or by any means. Electronic, mechanical, magnetic, optical,
chemical, manual or otherwise, without prior written permission of Unidata Pty Ltd 40 Ladner St,
O’Connor Western Australia 6163

Manual – Starflow Ultrasonic Doppler Instrument With
MicroLogger, Model 6526
Unidata Manual - 6526 Starflow User Manual Issue 17 01 2020.docx Contents 1
TABLE OF CONTENTS
1.0 Introduction .........................................................................................................................1
2.0 Operating Principles...........................................................................................................2
2.1 How Starflow Measures Velocity......................................................................................... 3
2.2 Speed of Sound in Water .................................................................................................... 4
2.3 Factors Affecting Data Accuracy......................................................................................... 5
3.0 Specifications...................................................................................................................... 6
3.1 Battery Duration Table ........................................................................................................ 6
3.2 Memory Duration Table....................................................................................................... 6
4.0 Installation ...........................................................................................................................8
4.1 Site Considerations ............................................................................................................. 8
4.2 Starflow Mounting................................................................................................................ 8
4.3 Power Considerations ....................................................................................................... 12
4.4 Starflow 9 Way Vented Cable Connection Table.............................................................. 12
4.5 Drying Tube and Desiccant ............................................................................................... 12
5.0 Starlog v4 starflow instrument only software installation ............................................ 12
6.0 Starflow Scheme Management ........................................................................................20
6.1 Scheme Editor................................................................................................................... 20
7.0 Programming starflow ......................................................................................................33
8.0 Test Mode ..........................................................................................................................35
8.1 Scheme Information .......................................................................................................... 36
8.2 Log Information.................................................................................................................. 36
8.3 Scheme Channels ............................................................................................................. 37
8.4 Log Buffers ........................................................................................................................ 37
9.0 Unloading Data from Loggers.......................................................................................... 39
10.0 Viewing Data......................................................................................................................41
10.1 Source Data File................................................................................................................ 41
10.2 Viewing the Data File ........................................................................................................ 42
11.0 Diagnostics........................................................................................................................ 44
11.1 Comms Window ................................................................................................................ 44
11.2 Upgrade Firmware............................................................................................................. 45
11.3 SDI-12 Test ....................................................................................................................... 46
11.4 Velocity Trace.................................................................................................................... 46
12.0 Velocity Histograms.......................................................................................................... 47
12.1Inherent Factors in Doppler Histograms ........................................................................... 49
12.2 Channel Characteristics Affecting the Signal .................................................................... 50
13.0 Flow Measurement Extensions........................................................................................ 59
13.1 Overview of Creating a Flow Scheme............................................................................... 59
14.0 Computer Communication ...............................................................................................69
14.1 Communications (Starlog) Protocol................................................................................... 69

Manual – Starflow Ultrasonic Doppler Instrument With
MicroLogger, Model 6526
Unidata Manual - 6526 Starflow User Manual Issue 17 01 2020.docx Contents 2
14.2 Memory Layout.................................................................................................................. 69
14.3 Hardware Register Information ......................................................................................... 69
14.4 Starflow - Instructions........................................................................................................ 70
15.0 Starflow SDI-12 Interface..................................................................................................71
15.1 Introduction........................................................................................................................ 71
15.2 Using Starflow as An SDI-12 Sensor ................................................................................ 72
15.3 Starflow SDI-12 Implementation Notes ............................................................................. 73
15.4 SDI-12 Test ....................................................................................................................... 74

Manual – Starflow Ultrasonic Doppler Instrument
Model 6526
Unidata Manual - 6526 Starflow User Manual Issue 17 01 2020.docx
Page 1
1.0 INTRODUCTION
The Starflow Ultrasonic Doppler Instrument is a unique combination of water velocity, depth and
temperature instruments integrated with a solid state logger.
By using digital signal processing techniques, Starflow is able to perform in a wide range of
environments. It is used to record flows in pipes, channels and small streams and operates in a
different range of water qualities from fresh streams to primary sewage channels.
The instrument is intended for economically recording flows in channels, culverts and pipes. It can
also be used where existing techniques are unsuitable or too expensive. It is particularly useful at
sites where no stable stage/velocity relationship exists and where flows are affected by variable tail
water conditions, culvert entry blockages, pipe surcharging, other unstable flow conditions, or even
reverse flows.
Starflow is mounted on (or near to) the bottom of the stream/pipe/culvert and measures the velocity
and depth of the water flowing above it.
This enables a complete stream study to be undertaken with a single instrument.
Models:
•5m depth range (Model 6526J-51 Starflow Kit)
•2m depth range (Model 6526J-21 Starflow Kit)
Starflow system consists of:
•Model 6526J Starflow instrument
•Model 6603DT Drying Tube and Desiccant.
•Model 6603D-SDI Adaptor cable for connecting a Starflow to a computer RS232 & battery
•Model 6526M-2 Stainless Steel Mounting Bracket
•Model 6307C-AUE STARLOG V4 (instrument only) Starflow Licence Key

Manual – Starflow Ultrasonic Doppler Instrument
Model 6526
Unidata Manual - 6526 Starflow User Manual Issue 17 01 2020.docx
Page 2
Accessories:
The following accessories should be purchased according to your application requirements.
•Model 6907B-14 12V, 14Ah Sealed Lead Acid Battery
•Model 6904I-10 10W Solar Recharge Panel & Mount
•Model 6904I-20 20W Solar Recharge Panel & Mount
•Model 6702S Starflow Weatherproof Enclosure
•Model 6705A Small Expanding Clamp SS expanding turn-buckle and band clips.
100mm wide, 100mm long, 50mm expansion.
Use in pipes up to 600mm (24") in diameter
•Model 6705B Large Expanding Clamp SS expanding turn-buckle and band clips.
100mm wide, 150mm long, 100mm expansion.
Use in pipes over 600mm (24") in diameter
•Model 6705D 1800mm Band Segment 100mm wide, 0.6mm Stainless Steel band
with 50mm spaced locating holes at both ends
•Model 6705F Band Joiner Stainless Steel joiner
2.0 OPERATING PRINCIPLES
The Starflow measures velocity, depth and temperature each scan interval (15 to 600 seconds)
and logs data according to your specification in the scheme. The measured data are logged and
then scaled and processed during presentation and processing.
The Starflow contains a 512K micrologger which controls the instrument’s operation and logs the
measurements:
Water Velocity in the vicinity of the Starflow is measured acoustically by recording the Doppler
shift from particles and microscopic air bubbles carried in the water.
Water Depth is measured using a solid state pressure sensor mounted underneath the Starflow
and vented to atmospheric pressure via a vent tube inside the signal cable.
Water pressure is sensed via a pressure damping manifold which has been designed to sense
depth in front of the velocity transducer.
The shape of the sensing manifold is designed to reduce velocity effects on the pressure sensor.
These effects are significant at velocities above 2m/sec.
The vent tube is opened to the atmosphere through the signal cable connector and a vent tube
desiccant canister is fitted to ensure moisture does not enter the vent tube.
Temperature is measured to refine the acoustic recordings. These are related to the speed of
sound in water, which is significantly affected by temperature.
Battery Voltage is measured to allow the Starflow to stop operating if the supply voltage is below
defined limits.
Flow, flow rate and total flow values are computed by Starflow from user defined channel
dimension information (see Flow Measurement Extensions on page 59). Alternatively, the flow
rate may be computed from the refined logged data using PC based computation of area x mean
from each logged point. Total flows are then accumulated as rate x time.

Manual – Starflow Ultrasonic Doppler Instrument
Model 6526
Unidata Manual - 6526 Starflow User Manual Issue 17 01 2020.docx
Page 3
The micrologger switches on the Starflow instrument once per scan. The scan rate is specified by
the user. Each time the Starflow switches on, it performs the following tasks:
Measurement – Each scan interval (user adjustable from 15 seconds to 10 minutes) the
micrologger switches the Starflow on. It then measures velocity, depth and temperature these
signals are then stored in the micrologger memory.
Analysis – The micrologger then performs data processing and analysis defined in the scheme
you have loaded. This includes averaging, maximum/minimum and totalizing calculations. Flow
computation is also performed at this time.
Communications – If a computer is connected to the Starflow instrument, the micrologger
establishes communications via the RS-232 channel. An SDI-12 interrogation sequence will also
be initialised at this time. Note: RS-232 and SDI-12 communications will occur simultaneously with
other operations.
Datalogging – When the scan occurs at a log interval (from 15 seconds to 1 week) the
micrologger records user defined measurement values (velocity, depth, flow, etc) into its memory
(log buffer). Here, the data remains until the Starflow is unloaded into a computer.
2.1 How Starflow Measures Velocity
When sound is reflected from a moving target the frequency of the sound is varied by the velocity
of the target. This variation is known as a Doppler shift. To measure water velocity in open
channels Starflow exploits the particles moving with the water as acoustic targets (or scatterers)
from an instrument fixed to the bed or bank.
There are two distinct types of Doppler instruments that can be used to measure water velocity:
Coherent (or profiling) Dopplers transmit encoded pulses with the carrier frequency at target
locations, and only measure signals reflected from these targets. This allows the velocity in a
stream to be profiled. These instruments are complex and expensive.
Incoherent (or continuous) Dopplers like the Starflow, emit a continuous signal and measure any
signals returning from scatterers anywhere and everywhere along the beam. These are resolved
to a mean velocity that can be related to a channel velocity at suitable sites.
During a measurement cycle, ultrasonic sound is transmitted continuously at a fixed frequency,
called a carrier. A receiver listens for reflected signals from any targets. A measuring circuit
detects any frequency changes. A processing system accumulates and analyses these frequency
changes and calculates a representative Doppler shift from the range received.
Each Doppler shift is directly related to the water velocity component along the beam. This is a
physical relationship and if you know the speed of sound in water you can calculate the velocity of
the reflector and thereby the velocity of the surrounding water. Starflow instruments do not need
calibration for velocity measurement.
The velocity measured is the component along the beam. As the beam is at an angle to the flow,
the Velocity is adjusted by the angle cosine.

Manual – Starflow Ultrasonic Doppler Instrument
Model 6526
Unidata Manual - 6526 Starflow User Manual Issue 17 01 2020.docx
Page 4
2.2 Speed of Sound in Water
Velocity measurements are directly related to the speed of sound in water. The factor used to
scale Starflow Velocity measurement is based on the speed of sound in fresh water at 20°C (see
table below). This velocity of sound gives a calibration factor of 0.550mm/sec per Hz of Doppler
shift.
This calibration factor may be adjusted for other conditions, for example the calibration factor for
sea water is 0.5618mm/sec/Hz.
The speed of sound varies significantly with water density. Water density is dependent on
pressure, water temperature, salinity and sediment content. Of these, temperature has the most
significant effect and it is measured by the Starflow and applied in the correction of velocity
measurements.
The Starflow corrects for the variation of the speed of sound in water due to temperature using a
factor of 0.00138mm/s/Hz/°C. This correction is a best fit for water temperatures between 0°C to
30°C. The following table shows how the speed of sound varies with temperature and between
fresh and sea water.
Temperature (ºC)
"Fresh Water"
"Sea Water"
0 1402 1449
5 1426 1471
10 1447 1490
15 1466 1507
20 1482 1521
25 1497 1534
30 1509 1545
35 1520 1555
Velocity of Sound in Water (m/s) at atmospheric pressure
Bubbles in the water are desirable as scatterers, but too many can affect the speed of sound. In air
the speed of sound is about 350 m/s.

Manual – Starflow Ultrasonic Doppler Instrument
Model 6526
Unidata Manual - 6526 Starflow User Manual Issue 17 01 2020.docx
Page 5
2.3 Factors Affecting Data Accuracy
Starflow measures velocity to an accuracy of ±2% and depth to ±0.25% of calibrated range. This
is logged to a resolution of 1 mm/sec and 1mm respectively. The transducers have been
calibrated and are expected to be stable for long periods provided they are not physically
damaged, blocked or buried.
The purpose of the Starflow system is to produce flow data. This is the product of the cross section
(derived from measured depth) and velocity data, each of which is modified by user defined factors
before use. There are many opportunities for errors to accrue in the process and degrade the
result. These can be reduced or eliminated by using the instrument properly. Some of the more
significant potential error sources follow.
2.3.1 Alignment with Flow
For the calibration to be valid, the transducer needs to be horizontally and vertically aligned with
the flow. While Starflows are calibrated pointing into the flow, they can be pointed downstream
with little loss of calibration accuracy. You may want to do this when fouling of the sensor face is a
problem. Any angled flow in the horizontal plane will reduce the recorded velocity. A 10 degree
angle will reduce the velocity recorded by 1.5%.
More significant errors will result from angled flow in the vertical plane. The sensors are
manufactured to project acoustic signals at 30° above horizontal when the sensor is mounted
horizontally. A 10° vertical flow angle change will cause errors of approximately +8.5% (@20°) and
–11.5% (@40°).
2.3.2 Instantaneous Versus “Averaged” Velocity
When you observe Starflow velocities, they will be seen to vary by 10% or more from scan to scan
at some sites. Because Starflow is very sensitive to variations in velocities, you are able to see the
natural velocity changes in the channel.
Although the discharge in a channel may be reasonably constant for a period of time, the velocity
distribution is always changing. Different velocity streams wander from side to side and bed to
surface as they progress down the channel. Turbulent swirls and eddies are carried downstream
for long distances while they slowly decay. Hydrographers will be used to having this action partly
removed by the mechanical inertia of a current meter and the period over which a typical
measurement is timed. However all will have noticed that the rate of revolutions of the current
meter varies during the timing period.
Continual velocity logging at one location with a Starflow will show these cyclic velocity pulsations.
The characteristics will be different for different sites and will vary with discharge. Cycles will
typically include short period fluctuations (a few seconds) overlaid on longer cyclic fluctuations (up
to many minutes). Longer term pulsations may also be seen particularly in larger streams when in
flood.
When comparing Starflow velocity and mechanical current meter readings, the display should be
observed long enough to estimate the mean of the readings. This should be adopted as the
logged velocity to compare with any check measurements.
When measuring velocity data Starflow samples for several seconds during each 1 minute scan. It
is recommended that all velocity measurements are averaged over the log interval. This attenuates
short frequency variations.

Manual – Starflow Ultrasonic Doppler Instrument
Model 6526
Unidata Manual - 6526 Starflow User Manual Issue 17 01 2020.docx
Page 6
2.3.3 Conversion of Logged to Mean Velocity
The logged velocity data may have to be adjusted during post processing to reflect a mean velocity
for the channel. The factors used will be site specific and have to be determined by the operator.
This is done by obtaining a mean channel velocity by conventional techniques and comparing it
with the average logged velocity. If necessary this process should be repeated at various
discharges.
Where the relationship is complex or unstable, the accuracy of this method is compromised.
In laminar flow conditions the channel mean velocity could be expected to be between 90% and
110% of the logged velocity.
In small channels (say a 500mm diameter pipe) the factor may be close to 100% as a
representative area of flow will have been “seen” by Starflow and contributed to the logged
velocity.
In larger channels only the area adjacent to Starflow will be “seen” and the relationship will depend
on how this portion relates to the vertical and horizontal velocity distribution in the channel. An
instrument located in the centre of the stream would normally be in a higher velocity area. However
in a deep channel Starflow may only see the slower portion of the velocity profile.
3.0 SPECIFICATIONS
3.1 Battery Duration Table
12V Battery Capacity Scan Rate
5 min 1 min* 15 sec
7Ah 130 days 26 days 7 days
12Ah 225 days 44 days 11 days
*Factory setting.
Battery Duration estimates assume battery is fully charged using a modern high quality charger.
Battery self-discharge will be higher at high ambient temperatures, and battery terminal voltage
available will be reduced at low ambient temperatures, which will reduce the above estimates.
These factors should be taken into account when sizing a battery. Where possible, an onsite
recharging system is recommended.
Due allowance must also be made for interrogation by computer/modem.
3.2 Memory Duration Table
Number of Parameters Recorded Log Interval
15 min* 10 min
Velocity & Depth (2) 300 days 250 days
Velocity, Depth & Temperature (3) 200 days 160 days
Velocity, Depth, Temperature & Battery (4) 150 days 125 days
*Factory setting.