Valeport MIDAS WLR User manual

© Valeport Limited
MIDAS WLR Hardware Manual Page 1 0730877D.doc
VALEPORT LIMITED
MIDAS WLR
Seabed Tide Recorder
Hardware Manual
Document Ref: 0730877
Document Version: D
Date: February 2007
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 therefrom, must not be disclosed to any other person whatsoever
without the prior written consent of the Company.
Valeport Limited, Tel: [phone]
St Peters Quay, Fax: [phone]
Totnes, e-mail: [email protected]
Devon, TQ9 5EW, Web: www.valeport.co.uk
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.
Copyright 2007

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CHAPTER DESCRIPTION PAGE
1INTRODUCTION...................................................................................................4
1.1 Contact Information ........................................................................................4
2SPECIFICATIONS ................................................................................................5
2.1 Sensor Specifications .....................................................................................5
2.2 Mechanical Specifications ..............................................................................6
2.3 Performance Specifications ............................................................................6
2.4 Sample Lifetime Calculations .........................................................................7
2.4.1 Based on Memory.....................................................................................7
A Note About Removable Memory....................................................................8
2.4.2 Based on Batteries ...................................................................................9
A Note About Rechargeable Cells ..................................................................10
3INSTALLATION...................................................................................................11
3.1 Communications With PC.............................................................................11
3.2 Deploying the MIDAS WLR............................................................................12
3.2.1 Real Time Operation...............................................................................12
3.2.2 Self Recording Operation .......................................................................12
3.2.3 LED Flashing Sequence .........................................................................12
3.3 Recovery ......................................................................................................13
4MAINTENANCE ..................................................................................................14
4.1 Changing Batteries .......................................................................................14
4.2 Seals.............................................................................................................16
4.2.1 O-Rings ..................................................................................................16
4.2.2 Anti-Extrusion Rings ...............................................................................17
5WIRING INFORMATION.....................................................................................18
5.1 Switch Plug...................................................................................................18
5.2 3m Y Lead (RS232) ......................................................................................18
5.3 3m Switched Y Lead (RS485 & RS422) .......................................................18

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1 INTRODUCTION
This manual covers the specification, wiring details and basic maintenance procedures
for the Valeport MIDAS WLR Seabed Tide Recorder. Full details of how to operate the
instrument with the DataLog Express software supplied are given in a separate manual.
As standard, the MIDAS WLR system consists of the following components:
•Titanium or acetal housed instrument
•Stainless steel deployment cage
•3m Y lead (interface to PC)
•Switching Plug
•Basic maintenance tools and spare o-rings
•DataLog Express Software CD
•Operating Manual
•Transit case
In addition, the following components may be supplied as optional extras:
•RS485 communications adaptor
•RS422 communications adaptor
•Bluetooth communications adaptor (19200 baud only)
•FSK modem communications adaptor (includes pcb in instrument)
•Various lengths & types of signal cable are also available
Note that 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.
1.1 CONTACT INFORMATION
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.

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2 SPECIFICATIONS
2.1 SENSOR SPECIFICATIONS
The unit is fitted with the following sensors:
Pressure
Type: Temperature Compensated Piezo-Resistive Sensor
Range: Various available, 10Bar (approx 100m water depth) to 600Bar
(approx 6000m water depth)
Precision: ±0.01% Full scale (±1cm for 10Bar sensor, ±0.6m for 600Bar)
Resolution: 0.001% Full scale (1mm for 10Bar sensor, 6cm for 600Bar)
Temperature
Type: Fast response PRT
Range: -5 to +35°C
Accuracy: ±0.005°C
Resolution: 0.001°C

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2.2 MECHANICAL SPECIFICATIONS
Materials
Housing: Titanium or acetal, as ordered
Exceptions: Temperature sensor is titanium.
Cage: Stainless steel (316 grade) with polypropylene clamping brackets
Dimensions: Instrument - 88mm Ø, 550mm long (including connector)
Cage – 750mm long x 140mm x 120mm
Weight (in cage): 11.5kg (air), 8.5kg (water).
Depth Rating: Acetal 500m (unless smaller pressure sensor fitted)
Titanium 6000m (unless smaller pressure sensor fitted)
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, 2 x 4mm bunch pins to external power, 9 pin female D
type to PC.
Switching Plug: 10 pin male Subconn line type (MCIL10M), with lock ring. Note
that the switch cap contains wiring links to activate the instrument
It is not a dummy plug.
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: 25mA at 12v when running, and 0.25mA when in sleep mode.
Sampling Rate: 1, 2, 4 or 8Hz (synchronised)
Data Output: RS232, RS485 or RS422, depending on pin selection. Baud rate
is user selectable from 2400 to 460800

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2.4 SAMPLE LIFETIME CALCULATIONS
2.4.1 BASED ON MEMORY
Lifetime based on memory is simple to calculate. Pressure values use 4 bytes of
memory per sample, and temperature uses 2 bytes. Therefore total memory used per
record is 4 + 2 = 6 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 over 2.7 million records.
The length of time that this memory will last for obviously depends on sampling
scenario. Here are two examples:
Continuous data sampling, 8Hz:
Memory used per second is 8 x 6 bytes = 48 bytes.
Total memory fitted is 16,777,216 bytes.
Seconds before memory full is 16,777,216 / 48 = (approx) 349,500 seconds.
This is equivalent to 97 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 6 bytes x 4Hz x 60 seconds = 1440 bytes.
The memory will therefore be full after 16,777,216 / 1440 bursts = 11650 bursts.
At a 10 minute cycle time, this is 116500 minutes, which is equivalent to 80 days.
Burst sampling, 4Hz, sampling 1 minute in every 10, recording averaged data:
Memory used per burst is 6 bytes.
The memory will therefore be full after 16,777,216 / 6 bursts = 11650 bursts.
At a 10 minute cycle time, this is 2796202 minutes, which is equivalent to 1941 days.

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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.

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2.4.2 BASED ON BATTERIES
The MIDAS WLR 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 25mA when sampling.
Total charge available is 5850mAh.
Number of hours available is therefore 5850mAh / 25mA = 234 hours.
This is equivalent to just less than 10 days.
For Lithium cells, a similar calculation gives around 23 days.
Burst sampling, 4Hz, sampling for 1 minute every 10 minutes:
At 12v, instrument draws 25mA when sampling, plus 21mA for 5 seconds at the
start of each burst. It draws 0.04mA when in sleep mode between bursts.
In this scenario then, the instrument will draw 25mA for 60 seconds, then 21mA for
5 seconds , and then 0.04mA for 535 seconds. On average, it will draw:
Total charge available is 5850mAh.
Number of hours available is therefore 5850mAh / 2.71mA = 2158 hours.
This is equivalent to approx 90 days.
For Lithium cells, a similar calculation gives approx 215 days.
The above examples are intended as guides only. Valeport accepts no
responsibility for variation in actual performance. Note that performance of
individual battery cells is not always consistent.
(25 x 60) + (21 x 5) + (0.04 x 535)
= 2.71mA
(60 + 5 + 535)

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A NOTE ABOUT RECHARGEABLE CELLS
We are often asked if rechargeable cells can be used. Yes, it is possible to use
rechargeable cells, but we do not recommend it:
•Firstly, the cells cannot be recharged in-situ due to the possibility of the cells
giving out gas inside a sealed instrument, effectively turning it into an explosive
device. Whilst this risk is small, it does exist and therefore must be considered.
The risk could be overcome by adding an air vent to the housing, but this could
compromise the water-tight nature of the housing. Better to remove the risk
altogether.
•Secondly, the most commonly used rechargeable cells are NiCad type. These
only operate at around 1.2v maximum and have about 25% of the capacity of an
alkaline cell; they therefore give greatly reduced operating times.
•Modern Li-ion or NiMH cells are more efficient than NiCad cells, but do not yet
compare with alkaline cells. They are also considerably more expensive.

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3 INSTALLATION
The standard system is supplied in an ABS transit case, together with any
communications adaptors ordered. Any additional lengths of signal cable are packed
separately.
3.1 COMMUNICATIONS WITH PC
The MIDAS WLR can be set up and interrogated using the DataLog Express software
supplied. Please refer to the separate manual for details of how to use the software.
To connect the instrument directly to a PC for RS232 communications, use the 3m Y
lead supplied. This lead is fitted with a 10 pin Subconn type connector, which should be
plugged directly into the connector on the top of the housing (or to a length of signal
cable). The lead also features 2 x 4mm bunch pins for application of external power if
required and a 9 way D type connector which should plug directly into a spare
communications port on the back of the PC.
If non-RS232 communications are to be used, via the optional RS485, RS422 or FSK
methods, then the appropriate adaptor should be used. Each adaptor is supplied with
an alternative Y lead, which should be connected as follows:
Comms
Method
Adaptor
Part No. Connections
RS485 0400029 Connect 15 pin D type and 4mm plugs from Y lead into
adaptor. Connect 9 pin D type from adaptor to PC, and 4mm
plugs from adaptor to external power, as indicated on adaptor
housing.
RS422 0400030 Connect 15 pin D type and 4mm plugs from Y lead into
adaptor. Connect 9 pin D type from adaptor to PC, and 4mm
plugs from adaptor to external power, as indicated on adaptor
housing.
FSK 0400005 Connect 4mm plugs from Y lead into adaptor, leaving D types
unconnected (FSK uses power and signal on just two wires).
Connect 9 pin D type from adaptor to PC, and 4mm plugs
from adaptor to external power, as indicated on adaptor

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3.2 DEPLOYING THE MIDAS WLR
All parts of the standard system (with the exception of the top part of the 3m Y lead) are
designed for immersion. All communications adaptors (RS485, RS422, FSK) are
splash proof, but should be sited in a dry place, as close to the PC as possible.
The MIDAS WLR is supplied with a stainless steel protective cage, but care should still
be taken not to damage the instrument. For profiling work, the recommended
deployment method is to suspend the instrument using the stainless steel wire strop
fixed to the top of the cage. For fixed deployments, the user may wish to remove the
cage, and use the grooves in the instrument housing as clamping points.
3.2.1 REAL TIME OPERATION
For real time data output, connect the signal cable to the 10 pin Subconn connector on
the instrument. All Valeport signal cables include a suspension point for strain relief,
and a similar arrangement is recommended for other cable types. Connect the top end
of the cable to a PC using the appropriate method as described above.
3.2.2 SELF RECORDING OPERATION
For self recording only deployments, the instrument is switched on by insertion of the
Subconn style switch plug. This plug must be inserted for the unit to operate.
Note that the switch plug is NOT just a dummy plug; it contains links between some of
the pins as described in Section 5, which are used to turn the instrument on.
3.2.3 LED FLASHING SEQUENCE
The MIDAS WLR is fitted with an LED visible through a polycarbonate window in the
battery pack. The LED will flash as detailed below to indicate various states.
Continuous ON
for 15 seconds
Occurs when the Switch Plug or cable is connected, indicating that
instrument is on and awaiting communication
1Hz Continual
Flashing
Insufficient Power. Change internal batteries, or completely remove
external power, and apply higher voltage
Continuous ON
for 2 seconds Indicates the start of Burst Sampling pattern
5 Rapid Flashes
Indicates the end of Burst Sampling pattern. The duration of the
burst may be calculated as the time between the start and stop LED
sequences, less 5 seconds.

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3.3 RECOVERY
On recovery, data can be extracted to PC via the 3m Y lead. This procedure is covered
in the separate software manual for DataLog Express.
To prolong the lifetime of the instrument the following procedures should be carried out
once the instrument has been recovered:
•Remove any significant growth from the instrument. A high pressure water jet or
stiff (not metal) brush is suitable – a hard toothbrush is ideal.
•Remove any significant growth from the pressure sensor port. Take care not to
introduce any sharp objects onto the sensor face – this may result in sensor
damage.
•Check instrument for signs of damage.
•Rinse the instrument in fresh water
•Dry the instrument if possible, paying particular attention to the sensors and
connector.
•Repack the instrument in the transit case provided.

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4 MAINTENANCE
The MIDAS WLR is completely solid state, and therefore requires very little
maintenance. Other than keeping the instrument relatively clean (as described in
Section 3.3, Recovery), the only procedure that the customer will be required to carry
out on a regular basis is to change the batteries. This Chapter also covers details of the
o-rings that are fitted to the instrument, and which should be checked periodically for
damage and replaced if necessary.
4.1 CHANGING BATTERIES
The MIDAS WLR accepts 8 x C cells, of either 1.5v alkaline or 3.6v Lithium type. These
cells are arranged in series, so the output voltage is 12v (alkaline) or 28.8v (Lithium).
Some example scenarios for lifetime of these batteries are given in Chapter 2.4.2
The batteries are located in a holder in the top of the instrument, and should be
accessed by removing the connector bulkhead.
1. (This step may be omitted)
For easier access, remove the instrument from the protective cage by loosening the
M10 nuts on the polypropylene clamps. Gently lever these clamps apart, using a
screwdriver if necessary.
Slide the instrument out of the cage, in either direction.
M5 screws
in this end

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2. Remove the 3 M5 x 20 socket cap screws in the connector bulkhead, using the Allen
key provided.
3. Without twisting or putting undue stress
on the Subconn connector slide the
bulkhead and attached battery pack out of
the main housing. A slot between the
tube and the bulkhead allows levering with
a screwdriver if necessary. Take care not
to scratch the bore of the tube.
4. A lead connects the battery pack to the electronics inside the tube. This may be
disconnected at the battery pack if required, for ease.
5. Replace the batteries.
6. Check the condition of the bore seal o-rings, and apply a light coating of silicon
grease. Ensure that both they and the anti-extrusion rings sit in the groove correctly,
and are free from damage. Replace them if necessary (refer to Section 4.2).
7. Reattach the connector to the electronics if necessary, and gently slide the battery
pack back into the tube, ensuring that the fixing holes are correctly aligned. Again,
take care not to scratch the bore.
8. Replace the 3 x M5 screws, using a small amount of copper grease (supplied). Do
not force the screws, just tighten firmly.
9. Finally, slide the instrument back into the protective cage. Note that the clamping
brackets are offset, and that the sensor end of the instrument should lie at the long
end of the cage.

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4.2 SEALS
The MIDAS WLR is kept watertight by using o-ring seals and anti-extrusion rings.
Double o-ring seals are used at each end of the housing, although the customer should
have no reason to open any seal other than that at the battery end.
A set of spare o-rings is included with the equipment. If an o-ring needs replacing, be
sure to use the correct size. If obtaining further spare o-rings from an alternative
source, be sure to obtain the correct material (signified by the last 4 digits of the o-ring
code number).
O-ring size: 200-143-4470
Anti-extrusion ring size: 143 (titanium housing only)
4.2.1 O-RINGS
To help preserve the watertight nature of the equipment, please observe the following
guidelines:
•Ensure that all o-rings are free from cuts, abrasions or perishing.
•Ensure that all-o-rings are free from dirt, grit, sand, hair and other foreign objects.
•With titanium housings, ensure that an anti-extrusion ring is fitted on the low
pressure side of each o-ring (see Section 4.4.2)
•Whenever an o-ring seal is opened (e.g. when changing batteries), ensure that a
light coating of silicon grease is applied to the o-ring before the seal is closed.
•Ensure that all o-ring protected seals are tightened.

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4.2.2 ANTI-EXTRUSION RINGS
It is common Valeport practice to fit Anti-Extrusion Rings, also known as AE Rings or
Backing Rings, to o-ring seals on deep water instrumentation.
The function of an AE Ring is to prevent the o-ring from being squeezed out of its
groove under high pressure. Whilst this may not immediately cause a leak, it can
damage the o-ring to the extent that it will not properly seal on subsequent
deployments.
Where an AE ring is fitted, Valeport favour a single solid ring type made
from nitrile rubber. These are black or dark grey in appearance, and are
distinguishable from the o-ring itself by having a square cross-section, with
a single concave surface, as illustrated:
These rings should be fitted into the o-ring groove on the “dry”, or low pressure side of
the o-ring, with the concave surface adjacent to the o-ring itself:
It is particularly important to note that in order to fit these rings, they must be stretched
slightly to pass over the instrument body. This stretch does not immediately recover,
with the result that the AE ring may not sit snugly in the groove at first. Fitting the tube
to the instrument at this point may result in the AE ring riding out of the groove, and
preventing a proper seal. The instrument may then leak.
Once an AE ring has been fitted, please leave a minimum of 30 minutes
for it to recover its shape before fitting the tube.
Water

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5 WIRING INFORMATION
5.1 SWITCH PLUG
10 Way
Male
Subconn Function
1 Link to Pin 10
2 NC
3 NC
4 NC
5 NC
6 NC
7 NC
8 NC
9 NC
10 Link to Pin 1
5.2 3M Y LEAD (RS232)
10 Way
Male
Subconn
3m Cable 1m Power
Cable
4mm
Banana
Plugs
1m Data
Cable
9 Way D
Type Function
1 WHITE BLUE BLACK Power Ground
2 PINK BROWN RED Power +V
3 N/C
4 N/C
5 N/C
6 N/C
7 GREY YELLOW 2 RS232 Tx (To PC)
8 BLUE BLUE 3 RS232 Rx (From PC)
9 GREEN GREEN 5 (link to
1,6,8,9) RS232 Ground
SCREEN SCREEN SHELL
10 YELLOW Internal Battery Enable
Link to RS232 Ground
5.3 3M SWITCHED Y LEAD (RS485 & RS422)
10 Way
Male
Subconn
3m Blue
Polyurethane
Cable
SWITCH BOX
1m White
Cable
4mm
Banana
Plugs
1m Grey
Cable
15 Way
D Type
0.2m Grey
Cable
9 Way D
Type Function
1 WHITE BLUE BLACK Power Ground
2 PINK BROWN RED Power +V
3 RED RED 9 RS422 TxA
4 BLACK BLACK 10 RS422 TxB
5 ORANGE VIOLET 11 RS422 RxA
6 BROWN BROWN 12 RS422 RxB
7 GREY YELLOW YELLOW 2 RS232 Tx (To PC)
8 BLUE BLUE BLUE 3 RS232 Rx (From PC)
9 GREEN GREEN 5 GREEN 5 (link to
1,6,8,9) RS232 Ground
SCREEN SCREEN SHELL SCREEN SHELL
10 YELLOW Internal Battery Enable