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TIIC 2016 North America:
Deep Water Senor system
University of Arizona
TI Innovation Challenge 2016 Project Report
Team Leader:
Matthew Barragan [email protected]
Team Members: Team Alex Yudkovitz [email protected]
Team Austin Nawrocki [email protected]
Team Nikitha Ramohalli [email protected]
Y
Advising Professor:
Yi Zhang [email protected]
Clayton Grantham [email protected]
Texas Instruments
Paul Frost [email protected]
Mentor (if applicable):
Project abstract (a short high level written description of the design and motivation behind
project), 1,000 words max:
The team was tasked with designing two PCBs that implemented a 4-20mA current loop
system, with a deep water data acquisition application. The system has two parts to it, the
remote station and the base station. The remote station, which is the part which is
submerged in water, has three sensors: a PH sensor, a temperature sensor and a pressure
sensor. The second part is the base station which is the heart of the system; it powers the
remote station through the twisted pair wire and also communicates with the remote station
through the same twisted pair. Communication is done by a HART signal, the base station
modulates the signal onto the power line and the remote station demodulates the signal and
switches sensors based on the signal. The sensors data is sent to the base station in the
form of 4-20 mA modulated signal, the base station has a current shunt to convert the current
into a voltage. This voltage is sent to an Analog-to-Digital converter which sends the digital
signal to the microcontroller. The microcontroller then sends the converted signal to a
computer over USB, is displayed on a Labview interface on the computer The Labview
program has tabs for each sensor, if you click on the sensor you want Labview sends a
command over USB to the microcontroller which then sends the signal to the Hart modem to
send the signal to remote station to change sensors. The HART modem on the remote
station will demodulate the signal and send a command to the microcontroller. The
microcontroller then sends the command to the LMP which is an Analog front end for the
sensors, to change to the correct sensor.
Qty.
1
List all TI analog IC or
TI processor part
number and URL
TPS62237
1) Explain where it was used in the project?
2) What specific features or performance made this
component well-suited to the design?
2MHz, 500mA Step-Down Converter, used to convert
5V from the XTR115 to 3.3V. It was selected to supply
enough current on start up to power all parts on the
remote station.
1
LMP91200
Integrated AFE for Low-Power pH Sensing
Applications, used since it was made for temperature
and PH sensors. The calibration port was used to
connect the pressure sensor.
1
XTR115
4-20mA Current Loop Transmitters, used for the
current loop but mainly chosen for the reference
voltage of 4.096V.
2
MSP430F5529
16-Bit Ultra-Low-Power Microcontroller, 128KB Flash,
8KB RAM, USB, 12Bit ADC, 2 USCIs, 32Bit HW MPY.
Used for the low power, and also for the 2 UART
connection and USB capability. It was the brains of
each system.
1
INA333
Low Power, Precision Instrumentation Amplifier, used
for the low power of 50μA, Zero-Drift, Rail-to-Rail. It
was used to amplify the pressure sensor by a gain of 2
before the LMP91200..
3
TLV314
LVx314 3-MHz, Low-Power, Low-Noise, RRIO, CMOS
Operational Amplifiers, chosen for its low power. One
is used for high impedance before the LMP91200
since the pressure sensor is also an amplifier. Another
is used for a gain of 4 after the LMP, and the last one
is used to shift the sensors’ voltage into 1-5V range so
it can be sent over the current loop.
1
SN74LV4T125
Single Power Supply Quadruple Buffer GATE w/ 3State Output CMOS Logic Level Shifter, chosen for its
4 channels. It was used to convert 3.3V logic to 5V
logic so the LMP91200 and MSP430 can
communicate.
1
ADS1220
Low-Power, Low-Noise, 24-Bit ADC for Small Signal
Sensors, chosen for its low noise and low power. It is
used to convert the sensors’ voltages to values for the
microcontroller.
Submit your TI Innovation Challenge project to the TI Project Repository.
Instructions:
● Project name must be labelled “TIIC 2016 North America: Project Name”
● Complete the project template provided on the webpage. Please include / attach:
o This TI project report
o Your full class report (max 30 pages; should include a detailed project
description, hardware design, software architecture and code, testing and
results, conclusions, acknowledgements & references, schematics, CAD
drawings, bill of materials, user manual, etc)
o Supplemental photos of your project
o A video of your project. We’d love to see your design in action!
Spring
Final Report
Sponsored By: Paul Frost (Texas Instruments)
Team: Matthew Barragan, Austin Nawrocki, Nikitha Ramohalli, Alex Yudkovitz, and Yi
Zhang
May 3, 2016
16
Table of Contents
1 INTRODUCTION
1.2 CONCEPT OF OPERATIONS DOCUMENT
1.2.1 PURPOSE OF THE DOCUMENT
1.2.2 PURPOSE OF THE PROJECT
1.2.3 SCOPE OF THE PROJECT
1.2.4 REFERENCES
1.2.5 BACKGROUND
1.2.6 CONCEPT FOR THE PROPOSED SYSTEM
1.2.7 SYSTEM OVERVIEW
1.2.8 OPERATIONAL SCENARIOS
1.2.9 CON OPS APPENDICES
2 SYSTEM REQUIREMENTS
2.1 FUNCTIONAL REQUIREMENTS
2.2 TECHNOLOGY REQUIREMENTS
2.3 PERFORMANCE REQUIREMENTS
2.4 UTILIZATION/CONSTRAINT REQUIREMENTS
2.5 TRADE-OFF/SYSTEM TEST REQUIREMENTS
2.6 TEST MATRIX
3 TOP LEVEL DESIGN OF FINAL CHOSEN CONCEPT
3.1 SYSTEM OVERVIEW
3.2 SCHEMATIC
3.3 MICROCONTROLLER
3.4 USER INTERFACE
3.5 SYSTEM CASE
4 BASE STATION SUBSYSTEM DETAILS
4.1 BASE STATION: HART MODEM
4.2 BASE STATION: ADC
4.3 BASE STATION: MICROCONTROLLER
4.4 BASE STATION: POWER SUPPLY
5 REMOTE STATION SUBSYSTEM DETAILS
5.1 REMOTE STATION: MICROCONTROLLER
5.2 REMOTE STATION: SENSORS
5.3 REMOTE STATION: XTR
10 BUDGET AND SUPPLIES
13 ANALYSIS
14 CONTINUING WORK
14.1 SUMMARY
15 CONCLUSION
15.1 SUMMARY
APPENDIX
APPENDIX A: SOFTWARE CODE
APPENDIX B: COMPLETE SYSTEM SCHEMATIC
1 Introduction
Within the process control industry, signal integrity in the presence of high noise
limits temperature, pressure, and pollution monitoring accuracy. The best recipe for corn
chips requires consistent, repeatable conditions. The 4-20 mA current loop is an ideal way
to transmit high integrity electrical signals and is an effective data transmission method,
especially in long-range applications. Texas Instruments (TI) has tasked Team 15044 with
utilizing this transmission method in order to gather sensor data in deep water
applications and display it on a user friendly Graphical User Interface (GUI). Highlighting TI
components, our system aims to be capable of sending critical data over long distances via
the 4-20 mA current loop. Designed and implemented on a printed circuit board (PCB), our
system aims to have the versatility to host different sensors, maintain high quality of the
signals displayed for the user, and survive deep water conditions. The system has been
built and tested and verify its functionality for a demonstration on Design Day 2016.
1.2 Concept of Operations Document
1.2.1 Purpose of the Document
This Final Report document serves to provide a system overview and final
conclusion on the design of this deep-water sensor system. This overview will describe the
environment of use, multiple views of the system, and will link the stakeholder’s view of
the device to the requirements. More specifically, it will define the scope, background,
concept for the completed system, and a broad system overview including results from the
completed system. The goal of this document is to give Texas Instruments and the
remaining stakeholders a complete understanding of the completed system.
1.2.2 Purpose of the Project
The purpose of this project is to design and build a prototype to demonstrate the 420mA current loop with modern Texas Instruments components. TI is the customer and
primary stakeholder for the project and requests a demonstration of the system at the
conclusion of the project. With sensor outputs in analog form, sending and processing the
data over long distance in the highest quality will be of the most importance. This is
delivered in a package capable of deep water sensing, accounting for obstacles and long
distance communication.
1.2.3 Scope of the Project
This project demonstrates the use of Texas Instruments components in deep water
applications and to provides an academic senior project for Team 15044. The scope of the
project was to design and validate a deep water sensor system that can communicate over
a long distance using a budget of $3,500. The sensor system comprises of TI components
measuring temperature, pressure, and water pollution (pH). This information is then
output from the sensors to a base station where it is represented visually to the user. A
functioning system is demonstrated and delivered to Texas Instruments on Design Day on
May 3rd 2016 at the University of Arizona.
1.2.4 References
Multiple websites provided by Texas Instruments offer background information on
relevant technology. These general documents describe the 4-20mA current loop as well as
the XTR117 board to be used. Specification sheets and data sheets are also included in the
document. Refer to Appendix A, Appendix B, Appendix C, and Appendix D for attached
reference documents.
1.2.5 Background
The concept of current loops was developed in the twentieth century. The idea
started in the HVAC industry in the form of pneumatic controls. Sensors, actuators and
controllers were powered by between 3 and 15 psi of air, in a situation where anything
below 3 psi was non-functioning. The term “live zero” refers to the fact that 3 psi was the
minimum pressure that the system would carry while operational. This technology was
later applied to the telephone industry for analog telephone communications using a 420mA current loop, where the 4mA is the live zero in the system. This technology is
commonly used for many industrial applications. Since the technology has been introduced
in the form 4-20mA current loops, most of the applications and implementations have
remained unchanged.
1.2.6 Concept for the Proposed System
The concept for the proposed system was used during the selection process
before the system was constructed. This section details the preliminary and selection
process for the system.
The system has a remote station and a base station that communicates over a long
distance using a tether of twisted-pair wire. The remote station has sensors that collect
data pertaining to temperature, pressure, and pollution data. The remote station then
sends the data to the base station where the base station processes the data to display it
onto a monitor. Below is a block diagram symbolizing these main components of the
system.
Figure 1.1: This is the basic model of the system. It demonstrates how each subsystem
interacts with one another as well as an overview of the entire system.
Figure 1.1 shows the basic concept and interactions of the system. The primary
components are the sensors (shown in green), the XTR116 (shown in red), the tether, and
the base station (shown in blue). The two wire tether shown connecting the base station to
the XTR116 is a primary focus for the communication in the project, and is the focus of
many of the requirements.
1.2.7 System Overview
The system uses the industry standard HART communication protocol and 4-20mA
current loops to transmit analog signals and provide a power supply between remote
station and base station over long distance in deep water. The remote station utilizes
multiple sensor probes to collect temperature, pressure and pH pollution data, converting
them to analog signals. The base station then converts analog signals to digital signals and
process them by the microcontroller. As a result, the user can remotely control and monitor
the environment under water.
1.2.8 Operational Scenarios
Below are three different scenarios that demonstrate some of the systems most
applicable capabilities.
The user will interact with the system by operating the base station. The user
interface allows the user to access the system’s information, including data pertaining to
temperature, pressure, and water pollution (measured in pH) gathered from the sensors.
By operating the system, the user is able to perform the following operational scenarios.
1.2.8.1 Scenario 1:
This scenario involves the water temperature sensor, system base station,
microcontroller, and GUI. After the base station and sensor system are both powered on,
these components allow the system to display the temperature of the water in degrees C.
From there, the user can continuously observe the temperature until the desired
information is captured.
Use Case: Access water temperature information
ID: 1.0
Brief Description: The user views water temperature information
Primary Actor: User
Secondary Actors: Temperature Sensor
Precondition: The user has powered on the system and its components
Main Flow:
a. The use case begins when the software begins sending and receiving
data.
b. Do continuously until the desired amount of information is received.
b.1. The user selects the temperature function and sends a
request for data through the GUI.
b.2. The sensor responds to the request by measuring
instantaneous water temperature.
b.3. The user reads the reported water temperature on the
screen of the base station via the GUI.
b.4. The request is ended and the sensor stops reporting
temperature data.
Post Condition: The user has data pertaining to the temperature of the water.
Alternative Flow:
b.2.1 The temperature sensor cannot establish communication with the base station.
b.2.2 The application displays an error message and prompts the user to calibrate the system.
b.4.1 The command to stop communication cannot be sent.
b.4.2 The application displays an error message and prompts the user to calibrate the system.
Table 1.1: This use case specification is for the operational scenario of displaying the water
temperature in degrees C. The above table goes through each step allowing the user to
achieve this functionality.
1.2.8.2 Scenario 2:
This scenario involves the water pressure sensor, system base station,
microcontroller, and GUI. After the base station and sensor system are both powered on,
these components allow the system to display the pressure of the water in PSI, as well as a
calculation converting this to water depth. From there, the user can continuously observe
the pressure and depth until the desired information is captured.
Use Case: Access water pressure and depth information
ID: 2.0
Brief Description: The user views water pressure and depth information
Primary Actor: User
Secondary Actors: Pressure Sensor
Precondition: The user has powered on the system and its components
Main Flow:
a. The use case begins when the software begins sending and receiving
data.
b. Do continuously until the desired amount of information is received.
b.1. The user selects the pressure function and sends a request
for data through the GUI.
b.2. The sensor responds to the request by measuring
instantaneous water pressure.
b.3. The user reads the reported water pressure on the screen
of the base station via the GUI.
b.4. The user selects the depth function on the base station GUI.
b.5. The microcontroller converts the water pressure into
depth using the pre-programmed conversion factors.
b.6. The user reads the reported water depth on the screen of
the base station via the GUI.
b.7. The request is ended and the sensor stops reporting
pressure and depth data.
Post Condition: The user has data pertaining to the pressure and depth of the water.
Alternative Flow:
b.2.1 The pressure sensor cannot establish communication with the base station.
b.2.2 The application displays an error message and prompts the user to calibrate the system.
b.5.1 The microcontroller cannot convert the pressure data into depth data
b.5.2 The application displays an error message and prompts the user to input relevant data.
b.7.1 The command to stop communication cannot be sent.
b.7.2 The application displays an error message and prompts the user to calibrate the system.
Table 1.2: This use case specification is for the operational scenario of displaying the water
pressure in PSI and depth in meters. The above table goes through each step allowing the user
to achieve this functionality.
1.2.8.3 Scenario 3:
This scenario involves the water pressure sensor, system base station,
microcontroller, and GUI. After the base station and sensor system are both powered on,
these components allow the system to display the pressure of the water in PSI, as well as a
calculation converting this to water depth. From there, the user can continuously observe
the pressure and depth until the desired information is captured.
Use Case: Access pH (water pollution) information
ID: 3.0
Brief Description: The user views water pollution information
Primary Actor: User
Secondary Actors: Light Sensor
Precondition: The user has powered on the system and its components
Main Flow:
a. The use case begins when the software begins sending and receiving
data.
b. Do continuously until the desired amount of information is received.
b.1. The user selects the pollution function and sends a request
for data through the GUI.
b.2. The sensor responds to the request by measuring
instantaneous light value.
b.3. The user reads the reported light value on the screen of the
base station via the GUI.
b.4. The microcontroller converts the light value into pollution
factor using the pre-programmed conversion factors.
b.5. The user reads the reported pollution factor on the screen
of the base station via the GUI.
b.6. The request is ended and the sensor stops reporting light
and pollution data.
Post Condition: The user has data pertaining to the pollution of the water.
Alternative Flow:
b.2.1 The light sensor cannot establish communication with the base station.
b.2.2 The application displays an error message and prompts the user to calibrate the system.
b.5.1 The microcontroller cannot convert the light data into pollution data
b.5.2 The application displays an error message and prompts the user to input relevant data.
b.6.1 The command to stop communication cannot be sent.
b.6.2 The application displays an error message and prompts the user to calibrate the system.
Table 1.3: This use case specification is for the operational scenario of displaying the water
pressure in PSI and depth in meters. The above table goes through each step allowing the user
to achieve this functionality.
1.2.9 Con Ops Appendices
1.2.9.1 Appendix A
http://www.ti.com/lit/ds/symlink/xtr117.pdf
1.2.9.2 Appendix B
https://www.acromag.com/sites/default/files/Acromag_Intro_TwoWire_Transmitters_4_2
0mA_Current_Loop_904A.pdf
1.2.9.3 Appendix C
http://www.ti.com/lit/ug/tidua04a/tidua04a.pdf
1.2.9.4 Appendix D
http://www.ti.com/lit/ug/tidu414/tidu414.pdf
2 System Requirements
Listed below are the requirements for the system derived from discussions with
Texas Instruments and the team. Requirements are categorized as functional, technology,
performance, utilization, trade-off, and system test requirements. Each requirement
includes information about the type of requirement, its description, source, status, priority,
and history.
2.1 Functional Requirements
Number
Type
1
Functional
2
3
4
5
6
Functional
Functional
Functional
Functional
Functional
Description
Source
Status
Priority
History
The system shall measure
temperature in degrees C
Texas
Instruments
Proposed
Must
Created
The system shall measure pressure
in PSI
Texas
Instruments
Proposed
The system shall quantifiably
measure water pollution
Texas
Instruments
Proposed
The system shall be controlled
through a graphical user interface
(GUI)
Texas
Instruments
Proposed
The system shall be water resistant
Texas
Instruments
Proposed
Texas
Instruments
Proposed
The system shall be able to
simulate communication over a
9-14-15
Must
Created
9-14-15
Must
Updated
9-17-15
Must
Created
9-14-15
Must
Created
9-14-15
Must
Created
9-17-15
longer than 1 Km tether
Table 2.1: Above is a table of functional requirements. These requirements were items that the
system should do to function as intended.
2.2 Technology Requirements
Number
Type
7
Technology
8
9
10
11
12
Technology
Technology
Technology
Technology
Technology
Description
Source
Status
Priority
History
The system shall integrate TI
components
Texas Instruments
Proposed
Must
Created
The system shall communicate at
least partially using analog signals
Texas Instruments
The system shall use no more than
20 mA
Texas Instruments
The system shall use between 18
and 36 Volts
Texas Instruments
The system shall use at least a 1 Km
long tether
Texas Instruments
The system must input and output
data from at least 3 sensors
Texas Instruments
9-14-15
Proposed
Must
Updated
9-17-15
Proposed
Must
Created
9-14-15
Proposed
Must
Updated
9-17-15
Proposed
Desired
Created
9-17-15
Proposed
Must
Created
9-17-15
Table 2.2: This table includes all of the technology components that the system requires.
2.3 Performance Requirements
Number
Type
13
Performance
14
15
Performance
Performance
Description
Source
Status
Priority
History
The system shall output
temperature measurements to
within 1 degree C
Texas Instruments
Proposed
Must
Created
The system shall output pressure
measurements to within 1 PSI
Texas Instruments
The system shall output pollution
measurements to within 10%
Texas Instruments
9-22-15
Proposed
Must
Created
9-22-15
Proposed
Desired
Table 2.3: The table above shows the requirements explaining how well the system should
perform.
Created
9-22-15
2.4 Utilization/Constraint Requirements
Number
Type
Description
Source
Status
Priority
History
16
Utilization
The system shall not cost more than
$3,500
The University of
Arizona
Proposed
Must
Created
The system shall be operable by one
person
Texas Instruments
Proposed
The system shall allow sensors to
be swapped without further
modification
Texas Instruments
17
18
Utilization
Utilization
9-22-15
Must
Created
9-22-15
Proposed
Desired
Created
9-22-15
Table 2.4: Above is a table of all of the constraints that the team must keep in mind while
building the system.
2.5 Trade-off/System Test Requirements
Number
Type
Description
Source
Status
Priority
History
19
Trade Off
The system functionality outweighs
the cost
Texas Instruments
Proposed
Must
Created
The system technology outweighs
the cost
Texas Instruments
The system component availability
outweighs the component
durability
Texas Instruments
20
21
Trade Off
Trade Off
9-22-15
Proposed
Must
Created
9-22-15
Proposed
Must
Created
9-22-15
Table 2.5: The trade-off requirements show the importance of technology, functionality, cost,
performance, and latency compared to each other.
2.6 Test Matrix
The test matrix below shows how each requirement is tested. The testing
verification is done either by a form of a test, analysis, or inspection. Test-based verification
is used when a measurement needs to be taken in order to substantiate the requirement.
An analysis-based testing is used when the desired measure and a physical measure are
linked through analysis. Finally, an inspection would entail a test that verifies if the
requirement were accounted for. To view the full requirements see the Requirements
section and refer to each by the “requirements number.” Refer to the acceptance test plan
to see how these will be tested.
Verification
Requiremen
t Number
Type
Description
T
(test)
A
(analysis)
1
Functional
Measure temperature
X
X
2
Functional
Measure pressure
X
X
3
Functional
Measure pollution
X
X
4
Functional
Include GUI
5
Functional
Water resistant
X
X
6
Functional
Communication distance
X
X
7
Technology
Integrate TI components
X
X
8
Technology
Analog communication
X
X
9
Technology
Current limitation
X
X
X
10
Technology
Voltage limitation
X
X
X
11
Technology
Tether length
X
X
12
Technology
Data output
X
X
13
Performanc
e
Temperature accuracy
X
X
14
Performanc
e
Pressure accuracy
X
X
15
Performanc
e
Pollution accuracy
16
Utilization
Cost
X
17
Utilization
User
X
18
Utilization
Sensor exchangeability
X
X
X
X
I
(inspection)
X
X
Table 2.6: The verification method that is marked with an “X” represents how the requirement
will be tested.
3 Top Level Design of Final Chosen Concept
3.1 System Overview
This section is a high level overview of the final design Team 15044 will proceed
with after the Preliminary Design Review. The main subsystems detailed in this section are
the base station and remote station schematic, the microcontroller, the user interface, and
the system casing.
While this is intended to be a top level overview of the design and the main
components will not change, some of the details may be changed based on new knowledge
Team 15044 acquires during the upcoming design phases.
Figure 3.1: A high level block diagram of the base station (left) and the remote station (right).
These top level concepts were derived from the preliminary design review concepts.
3.2 Schematic
The schematic is made by using the PCB designing tool Altium. The schematic
includes the base station and remote station. Team 15044 primarily uses Texas
Instruments components from the TI library which includes the MSP-EXP430F5529
microcontroller, ADS1220, INA149, XTR117 and also the HART modem modules and
sensors from other companies. Pins are connected correctly and function well. The
schematic is converted to PCB layout to be produced and used for the Design Day 2016
demonstration.
ADS1220
Figure 3.2.1: Detailed pin configuration and schematic drawings of some of the components
critical to the system schematic. These components are the ADS1220 (left) the AD5700 (right).
The complete system schematic, including both the base station and the remote
station are shown in Appendix E. The components in this diagram are the same ones as
listed above and show the pin to pin connections that are used. For simplicity, the
schematic is separated into multiple pages based on the primary components being
depicted.
3.3 Microcontroller
Team 15044 is using the MSP-EXP430F5529LP microcontroller from Texas
Instruments. This microcontroller was chosen because it has enough pins to control 4 SPI
devices or 2 UART devices. The microcontroller has integrated full speed USB 2.0, so it can
easily communicate with a computer for the user interface. The microcontroller is also low
powered so it can run off of the 4mA provided by the current loop.
Figure 3.3: A detailed pin configuration of the MS-430 series microcontroller. This pin
configuration will be used in the system schematic.
3.4 User Interface
The user interface is programmed in LabView by National Instruments. It consists of
three graphs, one for each sensor. The graphs are updated every 40 milliseconds, by having
the microcontroller switch between sensors and sent sensor’s data. The user can view the
data and can tell the program to stop recording data. Additional information about the user
interface and the software code can be found in Appendix D.
3.5 System Case
The case is a rectangular box which consists of a three holes for sensors and one
more hole for the communication line from the remote station to the base station. There
will be a lid that uses a silicone seal to keep out the water which is attached using four ⅛20 threaded screws. If testing is successful for a 3-D printing material which does not allow
water to diffuse through the solid printed material, then the model will be 3-D printed and
the holes will be hand threaded. To keep water out of the threaded hole for the pressure
sensor, Loctite will be used to prevent water leakage. Silicone will be used to seal the
remaining three access holes.
Figure 3.5: A Solidworks model of the system case. In this 3 dimensional diagram, the main
compartment and lid are shown, as well as the wiring and threaded holes.
4 Base Station Subsystem Details
The system comprises of a base station and a remote station. The base station
controls the remote station, and is where the user interacts with the system to complete
the use cases in section 1.2.8. The 4 primary components in the base station are the HART
Modem, the ADC, the microcontroller, and the power supply.
Below is a breakdown of each component including the component name and
specifications about that component. Interactions between each part can be found above in
detailed pin configurations and schematics in section 4.
4.1 Base Station: HART Modem
Component Name
AD5700
Power Supply
1.71-5.5 V
Input/Output
HART signal
Communication
UART with microcontroller
4.2 Base Station: ADC
Component Name
ADS1220
Resolution
24bit
Sample Rate
2kSPS(max)
Interface
Serial SPI
4.3 Base Station: Microcontroller
Component Name
MSP-EXP430F5529LP
Communication
4 SPI, 2 UART
USB Speed
Integrated Full Speed USB 2.0
Additional Features
Low Power Operation
4.4 Base Station: Power Supply
Component Name
CUI Inc. ETMA360166UD-P5P-IC
Voltage supply
36V
Max power output
60W
Max current output
1.66A
5 Remote Station Subsystem Details
This section details the components in the remote station subsystem. The remote
station, located a long distance away from the base station, is where the sensing takes
place. These components collect the data the user desires and sends that information back
to the base station. The 5 primary components in the remote station are the
microcontroller, the temperature sensor, the pressure sensor, the pH sensor, and the XTR.
Below is a breakdown of each component including the component name and
specifications about that component. Interactions between each part can be found above in
detailed pin configurations and schematics in section 4.
5.1 Remote Station: Microcontroller
Component Name
MSP-EXP430F5529LP
Communication
4 SPI, 2 UART
USB Speed
Integrated Full Speed USB 2.0
Additional Features
Low Power Operation
5.2 Remote Station: Sensors
Component Name (Temperature)
Minco RTD S667
Time Constant
1.3
Temperature Range
-50 to 155C
Features
Waterproof for continuous immersion
Component Name (pH)
American Marine Pinpoint pH probe
Passive properties
-59.16mV/pH
Temperature variation
.198 mV/pH/Celsius
Calibration zeros
pH of 7 at 25 degrees Celsius
Component Name (Pressure)
TE Connectivity Measurement Specialties
M3021-000005-10KPG
Output
0-100mV
Operating pressure
10,000 psi
Voltage Supply
2.5-12V
5.3 Remote Station: XTR
Component Name
XTR117 4-20mA Current Loop Transmitter
Loop Voltage
7.5-40 V
Output Zero Error (+/-) (Max) (uA)
0.4
Package Size (WxL) (mm2)
8SON
8VSSOP
10 Budget and Supplies
Below is a table detailing each anticipated component. For each, there is a column
showing the full name of the component, the price of the component, the required quantity,
and total price for each line.
The total budget allowed for the project is $3,500. Of that, team 15044 has
successfully stayed below the limit, anticipating incurring unplanned expenses towards the
end of the project. The total cost of the project according to the budget listed below is
$3,408.01.
Cost
Description
126.69 Altium Designer student license
61.80 Pinpoint pH replacement probe
121.34 AC/DC Adapter and transducer
75.00 (2) thermal tabs
167.44 Soldering Equipment
118.55 Measurement and Test Equipment
66.19 Pressure Sensor
70.10 IC AFE PH SENSOR 16TSSOP
430.57 10 Prototype 2-Layer Boards
886.20 Misc Components
433.67 10 Prototype 2-Layer Boards
30.85 Audio Cable, 22 Gauge, 2 Wires, 250' long
110.93 Acrylic Display
33.87 Waterproof Fittings
600.00 PCB Layout
74.81 Poster for Design Day
Total
$
3,408.01
Graphic 10.1: Above is a budget table. From the left, the columns show a detailed description
of the component, the estimated per unit cost of the component, the required quantity, and
the total price. The total cost is $3,408.01.
13 Analysis
Upon completion of the Deep-water Sensor System, Team 15044 prepared a
working interactive demonstration for Design Day 2016. Below are pictures of each of the
main components as detailed in this report, as well as calculations used for verification. For
additional information on complete system schematics, software, user interface
programming, and test results, see the Appendix sections at the end of the report.
Image 13.1: Above is a photograph of the completed system base station. This is a printed
circuit board based on the outlined base station schematics.
Image 13.2: Above is a photograph of the completed system remote station. This is a printed
circuit board based on the outlined remote station schematics.
These printed circuit boards are complete representations of both system
schematics. They include the Texas Instruments integrated circuits outlined in the sections
earlier in the report, as well as all resistors, capacitors, inductors, and other components
required to support the integrated circuits. These boards also feature connecting circuitry
to interface with the current loop, power supply, USB connection, and the three sensors.
Image 13.3: Above is a photograph of the pressure sensor package. The copper tube allows
pressure to accumulate and be sent to the remote station. This data can be validated by the
attached gauge.
The components in the pictures above are to be used in the Design Day 2016
demonstration. The PCBs will be on display and have been tested per the documents in
Appendix C. The Pressure Sensor Package allows for an interactive demonstration where a
viewer can see the analog gauge as well as a pressure readout on the GUI. This analog gauge
allows for validation of the pressure data being sensed and transmitted through the current
loop.
The temperature and pH sensor are validated by known conditions. The temperature
sensor is submerged into ice water, with a known temperature of 0 degrees C. This way we can
observe the temperature displayed to be 0 degrees C, and then increase to room temperature
when removed. The pH sensor will also be demonstrated in a similar way. It comes from the
manufacturer with known substances. The sensor can be exposed to these substances, and the
viewer can confirm the pH on the GUI.
Table 13.4: Above is a table showing each of the sensors with their designated attributes
including the model, description, properties, and known output.
Table 13.5: Above is a table referencing the op amp voltages and currents associated with
each sensor described in Table 13.4.
Table 13.6: Above is a table showing the currents expected for each sensor described in Table
13.4. The last column is the conversion rate to get the data into appropriate units to be
displayed on the GUI.
The above tables represent Team 15044’s calculations for each of the 3 sensors
highlighted in the project. Team 15044 used these tables to determine the expected voltages
and currents for each sensor, as well as what conversion rates were necessary to make the GUI
display the correct values.
After programing the GUI with the information in the tables, Team 15044 can confirm
the expected behavior of the system as described in the Use Case Scenarios in 1.2.8
Operational Scenarios. On Design Day 2016, viewers will not see these values, but instead
simple readouts from the sensors on the GUI.
14 Continuing Work
14.1 Summary
While Team 15044 effectively met all of its goals, there is still work that can be done to
further the project. The system works as a complete package, meeting all of its requirements.
However, if this project were to be extended, more requirements and actions could be taken.
First, the sensors could have been calibrated more thoroughly. While each of the
sensors is calibrated to a base value, this work could be continued to encompass the full range
of each sensor. This would allow the overall accuracy of the system to be higher.
Another area of the project that could benefit from expansion, is the aquatic
application. As the system is prepared for demonstration on Design Day, only the sensors have
water resistance. The remaining components of the system have not been verified for use
under water. If the project were to be continued, the remote station could be fully sealed in the
system case, and tested for a maximum depth pressure rating.
These extensions to the project would be valuable next steps for the team. As of Design
Day 2016, the system works as intended, but has opportunities for further advancement.
15 Conclusion
15.1 Summary
Team 15044, sponsored by TI, has collected and developed requirements,
constraints, and risks to design and implement their senior capstone project. This project,
using the design tools mentioned and outlined in this report has successfully designed,
build and validated the deep-water sensor system. Among many features, the system
measures temperature, pressure, and pH (pollution) from a deep water probe. This data is
processed by TI’s analog expertise using the XTR11x series products. The non-academic
benefit of this is that TI’s components are highlighted. The academic benefit is
demonstrated on Design Day, May 3rd, 2016 at the University of Arizona.
Appendix
Appendix A: Software Code
The software code for the communication between the base station and the remote
station is written in the C programming language. There is one “main” file for the base
station, and one separately for the remote station. This software is preprogramed onto the
MSP430 microcontrollers on each PCB.
The GUI software is programmed in Labview, with a sample user interface shown
below. The software will represents the following:
● A graphical output for each of the 3 sensors, temperature, pressure, and pH
● Visuals in Labview updated in real time
● Sampling at 40ms intervals
Table A.1: Above is a screenshot of the Labview interface. 3 graphs are shown, updating in
real time pressure, temperature and pH. Numerical input and start stop buttons are also
present.
Appendix B: Complete System Schematic
This section details the complete system schematic for the remote station and
the base station. The schematics show the pin to pin configurations as well as
necessary resistors, capacitors, inductors and other components.
Figure B.1: Above the first page of the base station schematic. The primary component being
depicted here is the MSP 430.
Figure B.2: Above the second page of the base station schematic. The primary component
being depicted here is the ADS5700.
Figure B.3: Above the third page of the base station schematic. The primary component being
depicted here is the ADS1220.
Figure B.4: Above the first page of the remote station schematic. The primary component
being depicted here is the AD5700.
Figure B.5: Above the second page of the remote station schematic. The primary component
being depicted here is the LMP and XTR.
Figure B.6: Above the third page of the remote station schematic. The primary component
being depicted here is the MSP430