Valeport MIDAS SVX2 User manual

MIDAS SVX2 Combined SV and CT Profiler -
Operating Manual
Document ID
MANUAL-1553401442-1 issue: 1.5
Date:
March 2022
This confidential document was prepared by the staff of Valeport Limited, the Company, and is the
property of the Company, which also owns the copyright therein. All rights conferred by the law of
the copyright and by virtue of international copyright conventions are reserved to the Company.
This document must not be copied, reprinted or reproduced in any material form, either wholly or in
part, and the contents of this document, and any method or technique available there from, must
not be disclosed to any other person whatsoever without the prior written consent of the Company.
© 2022 Valeport Ltd
Valeport Ltd
St Peter's Quay
Totnes TQ9 5EW
United Kingdom
Phone:
email:
Web:
[phone]
[email protected]
www.valeport.co.uk
As part of our policy of continuous development, we reserve the right to alter, without prior notice,
all specifications, designs, prices and conditions of supply for all our equipment

Contents
©2022 –Valeport Ltd
Page | b
Contents
1 Introduction..................................................................................................................................1
2 Specifications ..............................................................................................................................2
2.1 Sensor Specifications ...........................................................................................................2
2.1.1 Sound Velocity.................................................................................................................2
2.1.2 Conductivity .....................................................................................................................2
2.1.3 Pressure...........................................................................................................................2
2.1.4 Temperature ....................................................................................................................2
2.2 Mechanical Specifications ....................................................................................................3
2.2.1 Materials ..........................................................................................................................3
2.2.2 Connectors.......................................................................................................................3
2.2.3 Dimensions ......................................................................................................................4
2.3 Performance Specifications..................................................................................................5
2.4 Sample Battery Life Calculations .........................................................................................6
2.4.1 Based on Memory............................................................................................................6
2.4.2 Based on Batteries ..........................................................................................................8
3 Installation .................................................................................................................................10
3.1 Communications With a PC................................................................................................10
3.2 Deploying the MIDAS SVX2 ...............................................................................................10
3.2.1 Real Time Operation......................................................................................................10
3.2.2 Self Recording Operation ..............................................................................................11
3.2.3 LED Flashing Sequence................................................................................................11
3.2.4 Real Time Data Formats ...............................................................................................11
3.3 Data Download ...................................................................................................................12
4 Maintenance ..............................................................................................................................13
4.1 Changing Batteries .............................................................................................................13
4.1.1 Removing the End Cap Safely ......................................................................................14
4.2 Seals ...................................................................................................................................14
4.2.1 O-Rings..........................................................................................................................15
4.2.2 Anti-Extrusion Rings ......................................................................................................15
5 Wiring Information .....................................................................................................................16
5.1 Switch Plug .........................................................................................................................16
5.2 3m Y Lead (RS232)............................................................................................................16
5.3 3m Switched Y Lead (RS485) ............................................................................................17
6 Frequently Asked Questions .....................................................................................................18
7 EU Declaration of Conformity - CE Marking .............................................................................21

MIDAS SVX2 Combined SV and CT Profiler - Operating Manual
MANUAL-1553401442-1 | issue: 1.5
Page | 1
©2022 –Valeport Ltd
1 Introduction
This manual covers the specification, wiring details and basic maintenance procedures for the
Valeport MIDAS SVX2 Combined SVP / CTD Profiler. Full details of how to operate the instrument
with DataLog x2 software supplied are given in a separate manual.
As standard, the MIDAS SVX2 system consists of the following components:
•Titanium housed instrument
•Stainless steel deployment cage
•3m Y lead (interface to PC)
•Switching Plug
•Basic maintenance tools and spare o-rings
•DataLog x2 Software CD
•Operating Manual
•Transit case
In addition, the following components may be supplied as optional extras:
•RS485 communications adapter
•FSK modem communications adapter (includes pcb in instrument)
•Various lengths & types of signal cable are also available
Instruments are often supplied (on request) with minor adjustments to the above list, such as a
5m Y lead instead of a 3m Y lead for example. Such variations will be detailed on the
instrument packing list, and not in this manual.
If you have any questions about the operation of the instrument, which are not answered by this
manual, please contact your supplier if appropriate, or contact Valeport Ltd directly at the address
given at the front of this manual.

Section 2 | Specifications
©2022 –Valeport Ltd
Page | 2
2 Specifications
2.1 Sensor Specifications
The unit is fitted with the following sensors:
2.1.1 Sound Velocity
Type:
Valeport “time of flight” sound velocity sensor
Range:
1375 to 1900m/s standard.
Accuracy:
± 0.02m/s
Resolution:
0.001m/s
2.1.2 Conductivity
Type:
Valeport inductive coils
Range:
0 - 80mS/cm
Accuracy:
± 0.01mS/cm
Resolution:
0.002mS/cm
2.1.3 Pressure
Type:
Temperature Compensated Piezo-Resistive Sensor
Range:
600Bar absolute (approx 6000m water depth) standard. Others available.
Precision:
± 0.01% Full scale (±0.6m with a 600Bar sensor)
Resolution:
0.001% Full scale (0.06m with a 600 Bar sensor)
2.1.4 Temperature
Type:
Fast response PRT
Range:
-5 to +35°C
Accuracy:
± 0.01°C
Resolution:
0.002°C

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©2022 –Valeport Ltd
2.2 Mechanical Specifications
2.2.1 Materials
Housing:
Titanium
Exceptions:
Sound velocity sensor uses carbon composite rods.
Conductivity sensor is polyurethane and ceramic
Cage:
Stainless steel (316 grade) with polypropylene clamping brackets
Dimensions:
Instrument: 88mm Ø, 665mm long (including connector)
Cage: 825mm long x 140mm x 120mm
Weight (in cage):
13.5kg (in air) 9kg (in water)
Depth Rating:
6000m (unless smaller pressure sensor fitted)
2.2.2 Connectors
Instrument:
10 pin female SubConn bulkhead type (MCBH10F) with lock ring.
Comms Cable:
Valeport 3m Y lead. 10 pin male SubConn line type (MCIL10M) to instrument,
2x 4mm bunch pins to external power, 9 pin female D type to PC.
Switch Plug:
10 pin male SubConn line type (MCIL10M), with lock ring. Note that the switch
cap contains wiring links to activate the instrument.
The Switch plug is not a Dummy Plug

Section 2 | Specifications
©2022 –Valeport Ltd
Page | 4
2.2.3 Dimensions

MIDAS SVX2 Combined SV and CT Profiler - Operating Manual
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©2022 –Valeport Ltd
2.2.3.1 Pressure Sensor Offsets
2.3 Performance Specifications
Memory:
16Mb solid state memory (upgradeable in 16Mb steps to 64Mb)
Internal Power:
8 x 1.5v alkaline C cells. The unit will accept 8 x 3.6v Lithium C cells with no
alterations required
Do not mix battery types
External Power:
Between 9 and 30v DC.
Current Drain:
~60mA at 12v when running, and 0.25mA when in sleep mode.
Sampling Rate:
1, 2, 4 or 8Hz (synchronised)
Data Output:
RS232 or RS485 depending on pin selection. Baud rate is user selectable
from 2400 to 460800

Section 2 | Specifications
©2022 –Valeport Ltd
Page | 6
2.4 Sample Battery Life Calculations
2.4.1 Based on Memory
Battery life based on memory is simple to calculate. Conductivity, temperature and pressure
values use 2 bytes of memory per sample, and sound velocity uses 4 bytes. Therefore total
memory used per record is 4 + (3 x 2) = 10 bytes. Note that in Profile mode, each record is also
assigned a date/time stamp, which uses a further 7 bytes.
The 16 Mbyte memory actually contains 16,777,216 bytes. Allowing a small amount of memory
usage for header files, the memory will store almost 1 million records in Profiling mode, and over
1.6 million records in other modes.
The length of time that this memory will last for obviously depends on sampling scenario. Here are
three examples:
Continuous Data Sampling, 8Hz:
Memory used per second is 10 x 8 bytes = 80 bytes
Total memory fitted is 16,777,216 bytes
Seconds before memory full is 16,777,216 / 80 = (approx) 209,700 seconds
This is equivalent to 58 hours
This period could be doubled by sampling at 4Hz
Burst Sampling, 4Hz:
sampling 1 minute in every 10, recording all data points:
Memory used per burst is 10 bytes x 4Hz x 60 seconds = 2 400 bytes
The memory will therefore be full after 16,777,216 / 2400 bursts = 6 990 bursts
At a 10 minute cycle time, this is 69 900 minutes, which is equivalent to 48 days
Profiling, 6000m cast, measuring every 1 metre:
In this example, the instrument will take 1 reading every metre of both descent and ascent. This
means 6000 data points descending, and a further 6000 ascending. Each record consists of 10
bytes of data and 7 bytes of time stamp. Each record therefore uses 17 bytes. A single cast will
take 12,000 such records, and will therefore use 204,000 bytes.
The 16Mbyte memory will therefore hold approximately 82 casts of data.

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©2022 –Valeport Ltd
2.4.1.1 A Note About Removable Memory
We are sometimes asked whether we offer these devices with removable memory. The answer is
no we don’t, but there are sound reasons for this. It is natural to think that since removable
memory cards are now the norm in consumer electronics, they must be “state of the art” and
therefore desirable in all applications, but this is not necessarily the case.
•An essential feature of an underwater instrument is that it is water-tight; this is achieved by
using various seals on the mechanical parts of the device. Every time that one of these seals
is broken and remade, it introduces a small risk that the seal is not correctly made, and the
instrument could leak. The fewer times that the device has to be opened, the better –you
certainly wouldn’t want to do it after every profile to get the memory card out.
•All memory cards are susceptible to ESD shock (static electricity) while being handled. We
take the view that the value of your data means it shouldn’t be exposed to the possibility of this
risk, which could result in loss of all data on the card.
•Memory cards are not particularly efficient at storing data –they will only accept minimum
sized lumps of data at a time. This may be perfect for a camera where you instantly generate
a few Mbytes, not so for an application where you only want to store a few bytes of data at a
time.
•From a practical point of view, the time taken to connect a cable and extract the data to PC is
actually typically much less than the time to open the device, remove the memory, replace the
memory, and close the device up again.
•The implementation of removable memory is not technically difficult, but we believe that the
disadvantages currently outweigh any possible advantages in this product and its applications.
However, should circumstances change it will of course be considered for future product
enhancements.

Section 2 | Specifications
©2022 –Valeport Ltd
Page | 8
2.4.2 Based on Batteries
The MIDAS SVX2 will function with a voltage supply of between 9 and 30vDC. The voltage output
of the 8 x C cell battery pack will vary according to the type of cell fitted. The most likely cells to be
used will be standard alkaline type (1.5v each) or Lithium cells (3.6v each), giving a 12v nominal
output for alkaline cells, or 28.8v nominal for Lithium cells. The following calculations are based on
the same sampling scenarios as the memory calculations, using figures for a 12v alkaline battery
pack. Each example also gives a figure for a Lithium battery pack, calculated from a basic ratio of
alkaline to Lithium performance.
In all examples, it is taken that an 8 C cell alkaline battery pack will have a nominal capacity of
7.8Ah, and will be 75% efficient (total available charge, 5.85Ah), and that an 8 C cell Lithium pack
will have a nominal capacity of 7.2Ah, and will be 95% efficient (total available charge, 6.8Ah).
Continuous Data Sampling, 8Hz:
At 12v, the instrument draws 60mA when sampling.
Total charge available is 5 850mAh.
Number of hours available is therefore 5850mAh / 60mA = 97 hours.
This is equivalent to just over 4 days.
For Lithium cells, a similar calculation gives around 11 days.
The instrument is effectively operating continuously when in Trip sampling mode, so similar
calculations will apply.
Burst Sampling, 4Hz, Sampling for 1 Minute Every 10 Minutes:
At 12v, instrument draws 60mA when sampling, plus 60mA for 5 seconds at the start of each burst.
It draws 0.25mA when in sleep mode between bursts.
In this scenario then, the instrument will draw 60mA for 65 seconds, and then 0.25mA for 535
seconds.
On average, it will draw:
Total charge available is 5 850mAh.
Number of hours available is therefore 5850mAh / 6.72mA = 870 hours.
This is equivalent to approx 36 days.
For Lithium cells, a similar calculation gives approx 100 days.
The above examples are intended as guides only. Valeport cannot accepts responsibility for
variation in actual performance.
Performance of individual battery cells is not always consistent.