Transcript Built-In Test Software for Deformable Mirror High Voltage Drivers

Built-In Test Software for Deformable Mirror High Voltage
Drivers
Jianwei Zhou
Home Institution: University of Hawaii at Manoa
CfAO Akaimai Intership 2008
Subaru Telescope
Mentor: Stephen Colley
Funding provided by the Center for Adaptive Optics through its
National Science Foundation Science and Technology Center grant
(#AST-987683)
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Today’s Presentation
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Background Info
Design Discussion
Problems (Solved& Unsolved)
Results
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Acronyms
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A/D – Analog to Digital
D/A – Digital to Analog
BIT- Built-In Test
DM- Deformable Mirror
HV – High Voltage
ICD – In-Circuit Debugger
I2C – Inter-Integrated Circuit
LGSAO – Laser Guide Star Adaptive-Optics
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Project Overview
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Design Built-In Test (BIT) software for
deformable mirror high voltage driver in the
Subaru LGSAO system.
Measurement performed by BIT circuitry
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Input Voltages
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Output Voltages
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Power Supply Voltages
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Board Temperature
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Deformable Mirror (DM)
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DM is used with wavefront sensor to provided optical control and correction.
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DM operates with maximum voltages of +400V, and HV amplifiers with gain of 40
are used to amplify input voltages of + 10v to +400v.
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HV Driver Subsystem
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The HV driver subsystem in the Subaru LGSAO system
consist of 10 HV Amplifier boards
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High Voltage Amplifier Board
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Low Voltage
Connector
LV Input
Differential Input
Amplifiers
High Voltage
Connector
HV Amplifiers
HV Input
Amplifiers
HV Power
LV Power
Low Voltage
Regulator
Power
Build In Test
BIT
Network
LV Dividers
HV Dividers
MUX
AD
Converter
MC
Amplifiers
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Importance of Built-In Test Software
+ 10v
Digital
Real-Time
Control
Computer
Data
D/A
Converter
Board
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+ 400 v
HV
Amplifier
Board
w/BIT
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DM
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Built-In Test Circuit
Main components:
Analog Multiplexer
Analog-To-Digital Converter
Microcontroller (PIC 16F877)
Temperature Sensor
Mux
A/D
Converter
BIT
Circuit
Microcontroller
Temperature
Sensor
Host
Computer
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Programming
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Program Language use: C
Step 1: Program in C
Step 2: Compile to Assembly language by PICC STD.
Pros and cons
 C is easier and much shorter than assembly language
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Debugging require the knowledge of microcontroller
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Programming
5 Functions total:
MAIN+PORT+ MUX+ADC+I2C+TEMP
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Set Up
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Problem: The C compiler cannot installed and
compiled properly
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Solution: Read the user manual and get help
from product website
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Memory Constraint of Microcontroller
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Problems:
Programs must fit in the available on-chip program
memory ( very small compare to computer)
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Solution:
Must optimize the code to reduce the memory
I Displayed the measurement as character instead of int (char 8
bit, int 32 bits)
II Reduced the number of variable
III Reduced the lines of code whenever possible
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Low Level Programming
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Problems: Must understand the characteristic
of the hardware when programming
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Solution: Reading the data sheet of the
hardware.
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Debugging
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In-Circuit Debugger
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MPLAB IDE
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Results
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Tested the BIT circuit
1 bad A/D converter is found in one board
Fabrication error is found( The pin layout of temperature
sensor on the board is different from the schematic diagram)
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Measures the input voltages, output voltages, and power
supply voltages by the BIT software on a HV amplifier board
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A bug in the PICC STD is found ( cannot insert leading 0
with sprintf function)
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Work To Be Completed
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Run the BIT software in the whole LGSAO
system
Communication between the BIT circuit and
host computer (I2C)
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Personal Thought
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A valuable opportunity to learn about circuit
design
Application of the knowledge learnt in school
to real life practice
Increased research ability
Increased Confidence
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Acknowledgements
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Stephen Colley, Mentor
Sarah Anderson, Hawaii Island Internship Coordinator
Lynne Raschke, Science Communication Lead Instructor
Scott Seagroves, Science Communication Co-instructor
Lisa Hunter, Akamai Intership Director
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