Specification

Client A60N
Asset / Project iProbe Development
Doc Name Subsea Tool PCB Specification
Doc Number PR009-SPEC-001
Revision 0
Date 2nd May 2023

A60N Group Pty Ltd

28 Wickham Street, East Perth, Western Australia, 6004
ABN: 47612905549

By AZ Checked PG Approved PG

A60N Group Pty Ltd, is the owner or the licensee of all intellectual property rights in this document. The content of the document is protected by confidentiality and
copyright laws. All such rights are reserved. You may not modify or copy the document or any part of it unless we have given you express written consent to do so.
Table of Contents
1 iProbe Overview ......................................................................................................................................................... 3
2 Voltmeter Specifications ......................................................................................................................................... 3
3 PCB Overview .............................................................................................................................................................. 4
4 Firmware Overview: .................................................................................................................................................. 6

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1 iProbe Overview
This specification outlines a tool that can monitor and log AC & DC voltages, timestamps, and temperatures.

The key deliverables are the development of a circuit board featuring:

• 4 of each AC and DC voltmeters.

• A real-time clock for timestamping.
• A connection port for an LCD display (I2C)
• A thermocouple amplifier
• An RS-485 connection port for data logging/interfacing
• A light dependant resistor connection for activation via a flash of light.
• Flash memory to store data locally.

There are to be several iterations of the board, with the first being a general prototype to test the concept,
and the final design being optimised/improved to be installed in a waterproof enclosure. The main differences
between the prototype and final iteration are to be mainly related to quality of life, form, and firmware; the
key measurement functionality is needed in the prototype.

Deliverable Documentation:

• Copy of firmware code/relevant documentation

• Bill of Materials
• CAD/Gerber files
• Board Schematic
• Connection pinouts
• Delivery Schedule

As the measured quantities are to be small voltages, high input impedance (>10MOhm), is needed for the
voltmeter modules. The voltmeters also need to be auto ranging, as it will not always be feasible to manually
switch ranges, and several different voltages from different orders of magnitude may be encountered. Due
to this, the maximum voltage ranges are to be 1000VDC (if practically, else 50VDC) and 1000VAC RMS. The
DC voltmeter modules need to be able to read both positive and negative voltages.

The board will feature several DC and AC measurement modules, with each pair of voltmeters sharing inputs
so both the DC and AC voltage between the inputs can be measured for each set of voltmeters.

2 Voltmeter Specifications
DC Voltage AC Voltage (TRMS) Temperature

Range 50mV, 500mV, 5V, 50V, 50mV, 500mV, 5V, 50V, -20C to +100C
1000V 1000V
Accuracy 0.025% 0.4% 1.0%

Frequency Range 50Hz – 60Hz

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3 PCB Overview
Specification Implementation

Test PCB Final PCB

Input Power 5V-20V DC, 5V input, no battery. Li-Ion battery, charged via 5V-20V
Minimise power input.
consumption as a
priority.
Display Backlit LCD display, I2C connection port on board, for connection of remotely
50,000 Count** mounted LCD display.

RTC (Real- Provide Integrated on PCB. Must be resettable/programmable for

Time Clock) timestamps and operation in different time zones/drift.
countdowns.

Data capture Min/Max/Avg: Yes • Measure all listed values continuously during
and display Flash Memory: 1GB measurement sequence.
functionality • Log data to flash memory and out via Serial continuously
for this period.
• Display and save MAX and AVG readings of each data set
on display once measurement sequence has finished.
• Upload locally stored files onto PC as required via Serial.
Measurement Firmware performs base Customizable firmware, with
/Display functionality as described parameters modifiable via GUI.
Firmware below. Some basic Details listed in Firmware section.
parameters are customizable.
Activation Via 2x light flashes on Via light flash on remote
embedded LDR (Light mounted LDR (Light dependant
dependant resistor), within resistor). Number of flashes and
500ms of each other. interval is customizable via GUI.

Connection Port Connections Type

Voltmeter Inputs +VE & -VE 5.08mm pitch, 1.7mm diameter holes.
Thermocouple Inputs +VE & -VE 5.08mm pitch, 1.7mm diameter holes.
Serial Outputs (RS-485 in TX+, TX-, RX+, RX-, & GND 5.08mm pitch, 1.7mm diameter holes.
full duplex)
Power Inputs +VE & -VE 5.08mm pitch, 1.7mm diameter holes.
LCD I2C Port +VE, -VE, SDA, & SCL 5.08mm pitch, 1.7mm diameter holes.
LDR Inputs +VE & -VE 5.08mm pitch, 1.7mm diameter holes.

**Count refers to the resolution of the displayed figure. If the range is 5V, for example, the resolution of the
displayed voltage will be 5V/50,000 = 0.1mV. I.e., there are 50,000 steps between 0V and the maximum
measurable voltage in the measured range.

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A block diagram of the PCB showing all key components is shown below. While the actual PCB does not need
to mirror the exact placement of components/general layout of the diagram below, it must contain all the
key components shown.

Max size is to be 5cm x 15cm x 3cm tall, with a focus on keeping the PCB as compact as possible as well as
ensuring the inputs and outputs are as accessible as possible.

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4 Firmware Overview:

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During each measurement cycle, which is to be triggered via pulses of light to the LDR, the following
parameters are to be continuously polled from the PCB. The list numbers co-respond to the block numbers
in the diagram above, which serves as a block diagram of the PCB.

1. Timestamp
2. Measurement: DC
3. Measurement: AC RMS
4. Measurement: DC
5. Measurement: AC RMS
6. Measurement: DC
7. Measurement: AC RMS
8. Measurement: DC
9. Measurement: AC RMS
10. Temperature

In addition to the above listed parameters, there are several other parameters of interest that must be logged
for troubleshooting/maintenance. These are:

• Input voltage
• Battery Charger Module output voltage
• Battery Charger Module output current
• Flash Memory free and occupied space

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During the running of the measurement routine, these values are to be continuously outputted to a logging
computer via a RS-485 connection and logged to memory on the PCB, with the MAX and AVG readings for
each parameter to be displayed sequentially on the LCD display after the measurement routine has been
completed. The MAX and AVG functionalities are to work similarly to the MIN/MAX/AVG functions on a
regular multimeter.

Each of the parameters is to be formatted into a row, delimited by commas, with the final reading also having
a newline character appended, as to create a new row of readings with an updated timestamp as the
measurements are measured again.

The voltmeter inputs may be connected to titanium electrodes, which can drift in potential when placed in an
electrolyte. To mitigate this, each set of AC and DC voltmeters needs the ability to short its inputs together
when in standby, and briefly disconnect them when taking a measurement. These connections are to be
connected immediately prior to the relevant AC and DC modules being polled for a reading, then shorted
together immediately after. This figure below shows this process.

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The prototype will suffice with a simple and rigid measurement routine that can remain unchanged while the
final board will require some flexibility in its function. As there is only one signal available to give the board,
i.e., the light flash for activation, the ability to change aspects of the firmware via a GUI to optimise the board
for specific use cases will be required for the final board. The table below summarizes the basic features of
the proposed GUI, as well as what features are needed at different stages in the development cycle.

Functionality Prototype Final Default

Design
Set time/date for RTC. No Yes Set time at factory.

Set filenames for log file. TBD Yes

Create timestamp log for data post No Yes

processing.
Change measurement sequence No Yes Measurement sequence length: 30
parameters. seconds.
Measurement frequency: As fast as
practical.
Change trigger parameters. No Yes Number of flashes: 2x.
Flash separation: <500ms.
Download logged data. TBD Yes

Turn serial logging on/off. No Yes Serial Logging: On.

Change input shorting behaviour. No Yes

Change measurement display settings. No Yes Display each value for 5 seconds.
Repeat 2x.
Log/Graph incoming live data. No Yes

Graph logged/stored data sets. No Yes

Show battery capacity/charging state. No Yes

Show storage capacity. No Yes

This table is given to help aid hardware/firmware design, however, the development of the GUI itself is outside
of the scope of the project. The two criteria labelled “TBD” in the table above require implementation in the
prototype stage, however, do not necessarily require a GUI, just the ability to be performed.

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