UniData Communication Systems Starflow QSD 6527B User manual

Manual – Starflow QSD Model 6527B and 6537A
Unidata Manual - 6527B and 6537A Starflow QSD User Manual 08 05 2023.docx Page 1
Manual
Starflow QSD Model 6527B and 6537A
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 USA. 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 their 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.

Manual – Starflow QSD Model 6527B and 6537A
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Revision History
File name / Revision Date Authors & Change
Details
Checked/
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Unidata Manual - 6537A Starflow QSD SDI-12 User Manual 27 05 2019.docx 27 05 19 IM First Draft MS
Unidata Manual - 6537A Starflow QSD User Manual 21 06 2019 21 06 19 RDS, PD MS
Unidata Manual - 6537A Starflow QSD User Manual 04 07 2019.doc 04 07 19 CB KC
Unidata Manual - 6537A Starflow QSD User Manual 12 07 2019.doc 12 07 19 KC MS
Unidata Manual - 6537A Starflow QSD User Manual 17 07 2019 17 07 19 KC MS MS
Unidata Manual - 6537A Starflow QSD User Manual 28 10 2019.doc 28 10 19 CB PD
Unidata Manual - 6527B and 6537A Starflow QSD User Manual 27 11 2019.doc 27 11 19 IM CB
Unidata Manual - 6527B and 6537A Starflow QSD User Manual 17 01
2020.docx 17 01 20 IM Update EC Specs DM
Unidata Manual - 6527B and 6537A Starflow QSD User Manual 30 03
2020.docx 30 03 20 PD, RDS CB
Unidata Manual - 6527B and 6537A Starflow QSD User Manual 18 09
2020.docx 18 09 20 CB IM
Unidata Manual - 6527B and 6537A Starflow QSD User Manual 21 10
2022.docx 21 10 22 CB Update
SDI12/Modbus Specs IM
Unidata Manual - 6527B and 6537A Starflow QSD User Manual 08 05
2023.docx 08 05 23 CB Add logger
functionality KC
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Electronic, mechanical, magnetic, optical, chemical, manual, or otherwise, without prior written permission of Unidata Pty Ltd
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Manual – Starflow QSD Model 6527B and 6537A
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TABLE OF CONTENTS
Starflow QSD Model 6527B and 6537A ................................................................................1
1. Operation Mode........................................................................................................6
1.1. Operation Mode Configuring using SDI-12 protocol................................................... 6
1.2. Operation Mode Configuring using Modbus RTU protocol......................................... 6
2. Introduction ..............................................................................................................7
3. Specifications...........................................................................................................9
3.1. Velocity (Continuous Beam) ....................................................................................... 9
3.2. Depth (Ultrasonic) ....................................................................................................... 9
3.3. Depth (Pressure)......................................................................................................... 9
3.4. Temperature ............................................................................................................... 9
3.5. Electrical Conductivity (EC) – 6537A ONLY............................................................... 9
3.6. Tilt (accelerometer) ................................................................................................... 10
3.7. Power Requirements ................................................................................................ 10
3.8. Communications ....................................................................................................... 10
3.9. Environmental ........................................................................................................... 10
3.10. Physical..................................................................................................................... 10
3.11. Instrument Wiring Table............................................................................................ 11
4. Operating Principles & Measured Parameters ....................................................13
4.1 Flow Velocity Measurement...................................................................................... 13
4.2 Water Depth Measurement – Ultrasonic................................................................... 14
4.3 Water Depth Measurement - Pressure ..................................................................... 14
4.4 Temperature ............................................................................................................. 15
4.5 Electrical Conductivity EC 6537A Only..................................................................... 15
4.6 Accelerometer........................................................................................................... 15
4.7 Power Supply Voltage............................................................................................... 15
4.8 Signal Spread ........................................................................................................... 16
4.9 Received Signal Strength Indicator (RSSI)............................................................... 16
5. Taking Measurements From Instrument..............................................................17
5.1. SDI-12 Operation ...................................................................................................... 17
5.1.1. Channels Table 18
5.1.2. Measurement Command (aM!) 18
5.1.3. Additional SDI-12 Commands 20
5.1.4. Unidata Logger SDI-12 Scheme Setup 22
5.2. Modbus RS485 Operation ........................................................................................ 27
5.2.1. Reading the measured parameters via Modbus 27
5.2.2. Master Format 27
5.2.3. Slave Response Format 28
5.2.4. Standard Message Format 28
5.2.5. Modbus Registers 29

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5.2.6. Additional Modbus Commands 30
5.2.7. Unidata Logger Modbus Scheme Setup 32
6. Installation ..............................................................................................................38
6.1. Site Considerations................................................................................................... 38
6.2. Instrument Mounting – Pipes & Culverts .................................................................. 39
6.3. Instrument Mounting – Open Channels .................................................................... 41
7. Instrument Maintenance........................................................................................43
8. Factors Affecting Flow Measurement Accuracy .................................................44
8.1. Alignment with Flow and Depth ................................................................................ 44
8.2. Instantaneous Versus “Averaged” Velocity .............................................................. 44
8.3. Conversion of Logged to Mean Velocity................................................................... 45
8.4. The Speed of Sound in Water .................................................................................. 45
Starflow QSD Model 6527L .................................................................................................47
9. Starlog V4 Starflow QSD Instrument-Only Software Installation ......................47
10. Starflow QSD Scheme Management ....................................................................55
10.1. Scheme Editor .......................................................................................................... 55
10.2. Settings ..................................................................................................................... 57
10.3. Instruments ............................................................................................................... 58
10.4. Flow Measurement Extension .................................................................................. 60
10.5. Overview of Creating a Flow Scheme ...................................................................... 61
10.5.1. Creating an Area Rating Table 63
10.5.2. Partially Filled Pipe 63
10.5.3. Open Channel and Natural Stream 66
10.6. Other Applications..................................................................................................... 70
11. Configuring Starflow QSD.....................................................................................71
11.1. Configuring the Starflow QSD as an SDI-12 Sensor ................................................ 72
11.2. Configuring the Starflow QSD for Modbus RTU ....................................................... 74
11.3. Configuring Starflow QSD Settings........................................................................... 79
11.3.1. Log Buffer 83
11.3.2. Instrument Channels 83
11.3.3. Log Intervals 84
11.3.4. Saving the Scheme 85
12. Programming Starflow QSD..................................................................................87
13. Test Mode ...............................................................................................................88
13.1. Scheme Channels..................................................................................................... 89
14. Unloading Data from Loggers...............................................................................90
15. Viewing Data...........................................................................................................93
15.1. Starlog V4 (*.CSV) Files ........................................................................................... 93
15.2. Viewing the Data File ................................................................................................ 93
15.2.1. Graph View 94
15.2.2. Table View 94

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15.2.3. Opening with Notepad 95
15.2.4. Opening with Excel 95
16. Power Failure..........................................................................................................97
17. Diagnostics.............................................................................................................98
17.1. Velocity Trace ........................................................................................................... 98
17.2. Velocity Histograms .................................................................................................. 99
17.3. Inherent Factors in Doppler Histograms................................................................. 100
17.4. Varying Angles as Particles Pass through the Main Beam .................................... 100
17.5. Measuring Errors Due To “Signal Noise”................................................................ 101
17.6. Channel Characteristics Affecting the Signal ......................................................... 101
17.7. The Nature and Location of the “Reflectors” in the Water ...................................... 102
17.8. Velocity Variations Due to Cross-Section Changes ............................................... 103
17.9. Measuring Unexpected Velocities .......................................................................... 104
17.10. Measuring Turbulent Velocities .............................................................................. 105
17.11. Effects of Surface Ripples ...................................................................................... 106
17.12. Measuring Flows in Very Small Channels .............................................................. 107
17.13. Velocities Too Slow to Measure ............................................................................. 107
17.14. Measuring Velocities in Very Shallow Water .......................................................... 108
17.15. Interference to the Transducers.............................................................................. 108
17.15.1. Silt, Algae and Other Soft, Saturated Materials 108
17.15.2. Burying the Transducer in Sand 109
17.16. Initialise ................................................................................................................... 111
17.17. Configure ................................................................................................................ 111
17.18. Upgrade Firmware .................................................................................................. 112

Manual – Starflow QSD Model 6527B and 6537A
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1. OPERATION MODE
There are two modes of operation for the Starflow QSD, SDI-12 and Modbus RTU. SDI-12
operates so that when a Measurement command is sent, the Starflow QSD will Initiate a
read at this time and then provide data after 5 seconds. This allows for power saving as
the rest of the time, the unit is in a sleeping state. When the Unit is in Modbus RTU mode,
measurements are updated every 5 seconds, therefore, consuming more power. This is
required when measurements are required at faster rates. To set the Starflow QSD to
either SDI-12 mode (0) or Modbus mode (5).
1.1. Operation Mode Configuring using SDI-12 protocol
0 = SDI-12
* NOTE 5 = 5 second Modbus scan update or as per how often the Modbus registers are
required to update (5 is the minimum value)
To view the mode of operation, use the following SDI-12 commands.
Example 1 Examine:
Send – 0X8! <CR><LF>
Response – 0+0<CR><LF> (This shows the instrument is in SDI-12 mode).
Example 2 Change:
Send – 0X8+5! <CR><LF>
Response - 0+5<CR><LF> (This changes QSD from SDI-12 mode to Modbus mode)
1.2. Operation Mode Configuring using Modbus RTU protocol
0 = SDI-12
* NOTE 5 = 5 second Modbus scan update or as per how often the Modbus registers are
required to update (5 is the minimum value)
Example: Set Modbus 5 second update (default):
Send - 01 06 00 64 00 05 08 16
Receive - 01 06 00 64 00 05 08 16

Manual – Starflow QSD Model 6527B and 6537A
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2. INTRODUCTION
The 1st generation 6527 Starflow QSD Instrument measures water velocity, depth
(ultrasonic) and temperature. The Starflow QSD – 2nd generation has been enhanced to
include depth measurement using the hydrostatic pressure method (6527B Starflow QSD),
electrical conductivity (6537A Starflow QSD), and a tilt sensor that is useful for installation
and site monitoring. These models come standard with both SDI-12 and RS-485 (Modbus
RTU) interfaces.
The capacity of the instrument to measure the water conductivity is unique. It allows the
instrument to determine not only the water velocity, flow, and volume but also an indication
of the water quality. The conductivity measurement can also be used where existing
techniques for measuring water quality are unsuitable or too expensive. By using Digital
Signal Processing (DSP) techniques, the Starflow QSD can perform in a wide range of
environments. It is used to measure flows and water conductivity (6537A) in pipes, channels,
and small streams. It can operate in a range of water qualities, from fresh streams to primary
sewage channels.
The electrical conductivity feature of the 6537A instrument empowers the user to detect
unusual waste dumping/agriculture runoff that is not visible using current flow sensors. The
pressure depth sensor allows the instrument to be placed in an angled position on the wall of
irregularly shaped drainage canals or on the sides of channels in which it is difficult or
impossible to place the instrument on the channel floor.
The tilt parameter is measured by an internal accelerometer. It represents the pitch and roll
of the instrument’s body as it is installed, and its value is expressed in degrees of angle.
This provides the user with useful information about the sensor after being is mounted
underwater or during a post-installation inspection.
Starflow QSD system consists of the following:
Model 6527B or 6537A Starflow QSD instrument
Model 6527M Stainless Steel Mounting Bracket

Manual – Starflow QSD Model 6527B and 6537A
Unidata Manual - 6527B and 6537A Starflow QSD User Manual 08 05 2023.docx Page 8
6527B 6537A
Hardware 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 QSD Weatherproof Enclosure
Model 6705A Small Expanding Clamp SS expanding turnbuckle 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 turnbuckle 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

Manual – Starflow QSD Model 6527B and 6537A
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Instrument Accessories:
Model 6515 QSD Barometric Reference for pressure depth reading
compensation.
3. SPECIFICATIONS
3.1. Velocity (Continuous Beam)
Range
20mm/sec to 0.8 m/sec
20mm/sec to 1.6 m/sec (default)
20mm/sec to 3.2 m/sec
20mm/sec to 6.6 m/sec
Bidirectional velocity capability, set using configuration tools
Accuracy Typical ±1%
Resolution 1 mm/s
3.2. Depth (Ultrasonic)
Range 20mm to 5000mm (5m)
Accuracy ± 1% of the full scale
Resolution 1 mm
3.3. Depth (Pressure)
Range 0mm to 10m
Accuracy Typical ±0.19% for 0m to 5m range
Typical ±0.38% for 0m to 10m range
Resolution 1 mm
3.4. Temperature
Range 0°C to 60°C
Accuracy ±0.5°C
Resolution 0.1°C
3.5. Electrical Conductivity (EC) – 6537A ONLY
Range 0 to 200,000 µS/cm, typically ±1% of the measurement
Resolution ±1 µS/cm
It may be recorded as a 16-bit value (0 to 65,535 µS/cm) or
a 32-bit value (0 to 262,143 µS/cm)

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3.6. Tilt (accelerometer)
Range ±70° in roll and pitch axes.
Accuracy ±1° for angles less than 45°
3.7. Power Requirements
Voltage range 12 to 24 V DC
Supply current 50uA standby, 100mA active for 1 second @12V
Power source 12V DC - typically an external battery
3.8. Communications
SDI-12 SDI-12 v1.3
Connection Single cable up to 50 metres long (standard fitment is 15m)
Maximum cable 60m defined by SDI12.org
RS-485 Modbus RTU
Connection Single cable up to 300 metres long (standard fitment is 15m)
Baud rate and parity Configurable
3.9. Environmental
Operating 0°C to 60°C (water temperature)
Storage -20°C to 60°C
Humidity up to 100 % RH
3.10. Physical
Dimensions Approximately L 135 mm, W 55 mm, H 22 mm
Material Epoxy-sealed body, stainless steel mount
Weight 1kg with 15m of Cable
Cable 15 metre
Cable options User-specified, up to 50 metres

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3.11. Instrument Wiring Table
Variants for Wiring are detailed below.
Brown Wire Variant
Starflow QSD / Wire Colour Function / Signal Name
White SDI-12
Brown Power
Green Ground
Yellow A- (Modbus)
Pink B+ (Modbus)
Grey One-Wire *
Red Wire Variant
Starflow QSD / Wire Colour Function / Signal Name
White SDI-12
Red Power
Yellow Ground
Orange A- (Modbus)
Blue B+ (Modbus)
Grey One-Wire *
* Use with Unidata 6515 QSD Barometric Reference Module
When the Unidata 6515 QSD Barometric Reference module is connected, the instrument
will automatically handle the barometric correction and report the actual water level
instead of the water head plus atmospheric pressure.
Suppose your data logger has a barometric sensor. In that case, the data logger
program must perform the barometric correction, OR the user can perform a post-
processing method to correct for barometric changes by using barometric pressure data
from a trusted source such as a weather department or another barometer close by.
The 6515 QSD Barometer Reference module should be:
a) Mounted in an enclosure near the data logger in a position protected from the
elements.
b) The enclosure should be vented to expose the barometer sensor to atmospheric
pressure variations.

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6515 QSD barometric Connection Diagram:
There may be a small pressure offset when the sensor is first installed due to different
barometric conditions compared to the factory. This can be set to zero by applying a positive
or negative offset using a Modbus or SDI-12 command. Examples in sections 5.1.3.2 (SDI-
12) and 5.2.6.2 (Modbus RTU)

Manual – Starflow QSD Model 6527B and 6537A
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4. OPERATING PRINCIPLES & MEASURED PARAMETERS
The 6527B and 6537A Starflow QSD measure:
- Flow velocity
- Depth (ultrasonic)
- Temperature
- Depth (Pressure)
- Electrical Conductivity (EC) – 6537A Only
- Tilt (the angular orientation of the instrument)
The Starflow QSD performs data processing and analysis each time a measurement is
made. This can include rolling averaging and outlier/filter functions for Depth (ultrasonic),
Velocity, Depth (Pressure) and Conductivity (6537A). The function parameters can be
configured via SDI-12 eXtended command or Sonic software.
4.1 Flow Velocity Measurement
For measuring velocity, the Starflow QSD uses Continuous Mode Doppler. An ultrasonic
signal is transmitted into the water flow, and echoes (reflections) returned from particles
suspended in the water flow are received and analysed to extract the Doppler shift
(velocity). The transmission is continuous and simultaneous with the returned signal
reception.
During a measurement cycle, the Starflow QSD emits a continuous signal and
measures signals returning from scatterers anywhere and everywhere along the beam.
These are resolved to a mean velocity that can be related to a channel flow velocity at
suitable sites.
The receiver in the instrument detects reflected signals, and those signals are analysed
using digital signal processing techniques.
Internally the instrument auto-scales over these ranges if the range is manually set in
the settings: A bidirectional velocity capability is a supported option but needs to be
configured using Modbus or SDI-12 commands as the default setting is positive flow
only.
20mm / s to 0.8 m sec
20mm / s to 1.6m/s (default)
20mm / s to 3.2 m/s

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4.2 Water Depth Measurement – Ultrasonic
For depth measurement, the Starflow QSD uses Time-of-Flight (ToF) Ranging. This involves
transmitting a burst of ultrasonic signal upwards to the surface of the water and measuring
the time taken for the echo from the surface to be received by the instrument. The distance
(water depth) is proportional to the transit time and the speed of sound in water (corrected
for temperature and density). The maximum ultrasonic depth measurement is limited to 5m.
The minimum ultrasonic depth is 40mm above the ultrasonic eye.
NOTE: If there is a large ripple on the surface of the water due to windy conditions, this may
cause erratic Ultrasonic depth readings as it will not be able to resolve the correct
reflections; in these cases, the Pressure depth sensor will need to be used.
4.3 Water Depth Measurement - Pressure
Sites where the water contains large amounts of debris or air bubbles, may be unsuited for
ultrasonic depth measurement. These sites are better suited to using pressure to determine
the water depth.
The pressure-based depth measurement may also be applicable to sites where the
instrument cannot be located on the floor of the flow channel or cannot be mounted
horizontally.
The Starflow QSD is fitted with a 2 bars absolute pressure sensor. The sensor is located on
the bottom face of the instrument and utilises a temperature-compensated digital pressure
sensing element.
Where depth pressure sensors are used, the atmospheric pressure variation will cause
errors in the indicated depth. This is corrected by subtracting the atmospheric pressure from
the measured depth pressure. A barometric pressure sensor is required to do this.

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If the data logger used to read the Starflow QSD does not incorporate a barometric pressure
sensor, then the One Wire Bus 6515 Reference Barometer option should be purchased.
6515 should be mounted near the logger and is read by the Starflow QSD instrument, which
will then automatically compensate for the atmospheric pressure variations ensuring an
accurate depth measurement is achieved. This enables Starflow QSD to report actual water
depth (pressure) instead of barometric pressure plus water head.
4.4 Temperature
A solid-state temperature sensor is used to measure the water temperature. The speed of
sound in water and its conductivity are affected by temperature. The instrument uses this
measured temperature to compensate for temperature variations automatically.
4.5 Electrical Conductivity EC 6537A Only
The 6537A Starflow QSD is equipped with the capacity to measure the conductivity of the
water. A linear four-electrode configuration is used to make the measurement. A small
current is passed through the water, and the voltage developed by this current is measured.
The instrument uses these values to calculate the raw uncorrected conductivity.
Conductivity is dependent on the temperature of the water. The instrument uses the
measured temperature to compensate for the returned conductivity value. Both raw and
temperature-compensated conductivity values are available.
4.6 Accelerometer
The Starflow QSD has an integral accelerometer sensor to measure the inclination of the
instrument. The sensor returns the roll and pitch angle of the sensor (in degrees). This
information can be useful in ensuring the installation position of the sensor is correct and for
determining if the instrument has moved (bumped or washed away) during the post-
installation inspection.
4.7 Power Supply Voltage
The instrument’s internal power supply voltage is readable as a measurement parameter.
The operating range of the power supply is 12 to 24V DC. If the supply voltage falls below
defined limits, the instrument stops taking measurements to ensure only quality data is
measured.

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4.8 Signal Spread
This can be used to determine the amount of “turbulence” affecting the signal quality and
used to reject the measurement if the spread (turbulence) is too great. A good flow would
return a spread value of around 50; anything above 100 would be considered poor.
Spread Channel Interpretation:
0-50 Excellent SPREAD
60-200 Average SPREAD
200-500 Poor SPREAD
Above 500 Above 500 gives unreliable velocity data.
4.9 Received Signal Strength Indicator (RSSI)
The RSSI channel is the measurement of the received signal power. RSSI values may
change significantly for each measurement because of the number of reflectors in the water
at any given time.
In turbulent water, the reflectors are more likely to be in suspension, resulting in higher
signal/RSSI values. Subsequently, the smoother flowing water “may” have fewer reflectors
and lower signal/RSSI values. However, signal/RSSI values are dependent, not only on the
turbulence but on fluid velocity as well.
RSSI Channel Interpretation:
0 No Signal
3-200 Typical signal in water
>1000 Not usable Signal (Too Noisy)

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5. TAKING MEASUREMENTS FROM INSTRUMENT
The Starflow QSD instrument has both SDI-12 and RS485 (Modbus RTU) Interfaces. The
following sections describe them in detail. If you are a user of Unidata NRL loggers, you can
simply add the Starflow QSD as an instrument within the logging scheme as an SDI-12
instrument.
5.1. SDI-12 Operation
The Starflow QSD can be operated as a standard SDI-12 (V1.3) sensor.
Measurement commands (M! & C!) return atttn(n) response with ttt indicating the delay until
measurements are ready and n(n) indicates the number of parameters returned.
A Service Request is sent.
- The R! command returns an acknowledge response a<CR><LF>
- The D! command returns the measured data values.
SDI-12 Command Notes:
1. Change Address aAb! is supported.
2. Start Verification aV! returns an acknowledge response.
3. Extended Command aX is supported (refer to QSD SDI-12 supplement document).
4. D/R1…9! Commands operate the same as a D/R0! command.
5. M/C1...9! Commands operate the same as an M/C! command.
6. MC, CC & RC commands requesting CRC are supported.
Note: CRC is always recommended

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5.1.1. Channels Table
The Starflow QSD has a list of data registers within the instrument that are re-mapped to
SDI-12 channels. These SDI-12 parameters are assigned to the Channels, and their order of
return can be configured using SDI-12 eXtended commands. The channel allocation is
shown in the below table:
Channel Description Units Example Meaning
0 Water Temperature 1/10 ºC +152 15.2ºC
1 Battery Voltage 1/100 Volts +1302 13.02Volts
2 Ultrasonic Depth mm +123 123mm
3 CW Water Velocity +/- mm/s -234 234mm/s -ve flow
4 RSSI (signal level) no units +66 66 (no units)
5 Signal Spread no units +45 45 (no units)
10 X-Axis Tilt +/- deg -9 9 deg left tilt
11 Y-Axis Tilt +/- deg 7 7 deg forward tilt
12 Pressure Depth +/- mm +123 123mm
13 Barometric Reference + mm [phone]mm
70 Conductivity (UC) µS/cm [phone]µS/cm
72 Conductivity (TC) µS/cm [phone]µS/cm
5.1.2. Measurement Command (aM!)
6527B/6537A Starflow QSD measures several parameters available for collection by a data
logger. The default configuration returns nine parameters using the aM! command. Other
sets of parameters are also available using the aMx! commands.
Example 1: aM!
Parameter Description Units Example Meaning
1 Water Temperature 1/10 ºC +152 15.2ºC
2 Battery Voltage 1/100 Volts +1302 13.02Volts
3 Ultrasonic Depth mm +123 123mm
4 CW Water Velocity +/- mm/s -234 234mm/s -ve flow
5 RSSI (signal level) no units +66 66 (no units)
6 Signal Spread no units +45 45 (no units)
7 Conductivity (TC) µS/cm [phone]µS/cm
8 Pressure Depth +/- mm +123 123mm
9 Barometric Reference + mm [phone]mm
Start Measurement Command (aM!) example:
0M! 00059 <CR><LF> (Measurement ready in 5 seconds and nine parameters available)
0D0! 0+152+1302+123+234+66+45+2340+123+10120 <CR><LF>

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Example 2: aM1! (Firmware 20 and above)
Parameter Description Units Example Meaning
1 Water Temperature 1/10 ºC +152 15.2ºC
2 Battery Voltage 1/100 Volts +1302 13.02Volts
3 Ultrasonic Depth mm +123 123mm
4 CW Water Velocity +/- mm/s -234 234mm/s -ve flow
Start Measurement Command (aM1!) example:
0M1! 00054 <CR><LF> (Measurement ready in 5 seconds and 4 parameters available)
0D0! 0+213+1343+123+234<CR><LF>
Example 3: aM2! (Firmware 20 and above)
Parameter Description Units Example Meaning
1 Pressure Depth +/- mm +123 123mm
2 Barometric Reference + mm [phone]mm
Start Measurement Command (aM2!) example:
0M2! 00052 <CR><LF> (Measurement ready in 5 seconds and 2 parameters available)
0D0! 0+123+10120 <CR><LF>
Example 4: aM3! (Firmware 20 and above)
Parameter Description Units Example Meaning
1 Conductivity (UC) µS/cm [phone]µS/cm
2 Conductivity (TC) µS/cm [phone]µS/cm
Start Measurement Command (aM3!) example:
0M3! 00052 <CR><LF> (Measurement ready in 5 seconds and 2 parameters available)
0D0! 0+2350+2350 <CR><LF>

Manual – Starflow QSD Model 6527B and 6537A
Unidata Manual - 6527B and 6537A Starflow QSD User Manual 08 05 2023.docx Page 20
Example 5: aM4! (Firmware 20 and above)
Parameter Description Units Example Meaning
1 X-axis Tilt +/- deg -9 9 deg left tilt
2 Y-axis Tilt +/- deg 7 7 deg forward tilt
Start Measurement Command (aM4!) example:
0M4! 00052 <CR><LF> (Measurement ready in 5 seconds and 2 parameters available)
0D0! 0-9+7 <CR><LF>
Example 6: aM5! (Firmware 20 and above)
Parameter Description Units Example Meaning
1 RSSI (signal level) no units +66 66 (no units)
2 Signal Spread no units +45 45 (no units)
Start Measurement Command (aM5!) example:
0M5! 00052 <CR><LF> (Measurement ready in 5 seconds and 2 parameters available)
0D0! 0+66+45 <CR><LF>
Note: More information on C! And R! Commands can be found in the QSD SDI-12 supplement
document.
5.1.3. Additional SDI-12 Commands
5.1.3.1. Operation Mode
0 = SDI-12
5 = 5 second Modbus scan update or as per how often the Modbus registers are required to
update (5 is the minimum value)
Example 1 Examine:
Send – 0X8! <CR><LF>
Response – 0+0<CR><LF>
Example 2 Change:
Send – 0X8+5! <CR><LF>
Response - 0+5<CR><LF>