low cost 40mhz rf power meterseniord.ece.iastate.edu/.../18107271/sd2designdoc_final.docx · web...
TRANSCRIPT
Low Cost 40Mhz RF Power Meter
Design Document
Group: DEC13-04
Low Cost 40Mhz RF Power Meter March 10, 2013
TEAM COMPOSITION
SENIOR DESIGN, TEAM: DEC13-04
Jason Danielson
Jiwei Xia
Tyler Christensen
Yilun Ji
CLIENT
PowerFilm,Inc
Dan Stieler
ADVISER
Dr. Ayman Fayed
1
Low Cost 40Mhz RF Power Meter March 10, 2013
Executive Summary 2
System Design
System Requirements 3
Non-Functional System Requirements 4
Functional Decomposition
System Analysis 5
Detailed Design
Input/output Specification 6
User interface Specification 6
Hardware Specification 6
Software Specification 7
Software Design 7
Prototyping/testing 8
Circuit Design 8
Instruction Manual 9
Team Members 12
2
Low Cost 40Mhz RF Power Meter March 10, 2013
Executive Summary
Powerfilm, Inc. uses RF power generators to create a plasma enhanced chemical vapor for deposition of thin film solar cells. Since monitoring this area of operation is critical for production costs and end use performance, we’ve decided to upgrade an existing wattmeter with value added features. The addition of a digital readout, wireless transmission of the readings to a computer, and logging software will increase the value of the wattmeter and decrease the time needed to use it.
System Design
1. System Requirements
The requirements of this project are to take an existing RF wattmeter and change the output from an analog signal to a digital signal. Data from many meters will be sent to a database to keep a log of the power readings from the meters. A software program needs to be designed to communicate between a computer and the device, logging the data it gets. The unit will be powered by a DC source from the wall.
3
Low Cost 40Mhz RF Power Meter March 10, 2013
2. Non-Functional System Requirements
The Software Program needs to be able to do Real-time data logging and display.
Our GUI looks like this:
As requested, it will have a control panel which makes the program connect or disconnect to the microcontroller, in this case the MSP430G2553. Also, it requires continuous plotting of data and the ability to adjust the updating frequency. There is an option to save the data to a local drive or upload to a server for future use.
4
Low Cost 40Mhz RF Power Meter March 10, 2013
3. Functional Decomposition
Analog signal coming from RF Generator enters the Bird meter. Our unit intercepts the signal that would have normally been
processed by the analog needle and sends to an amplifier. The output from the amplifier is sent to the microcontroller for
processing and displays the value on a LCD display. Microcontroller sends processed data to the computer via Xbee
modules for the value to be logged and displayed by our software.
4. System Analysis
5
Low Cost 40Mhz RF Power Meter March 10, 2013
Detailed Design
1. Input/output Specification
Input into the watt meter is RF power at 40 MHz with variable frequency. This power will range between 160-1000W. The output of the watt meter is to be determined by testing different frequency inputs. The output of the watt meter is directed first to an amplifier and then to the microcontroller to convert the signal from analog to digital. Xbee modules are used to connect the device to a computer for logging of the data.
2. User interface Specification
There is an LCD display connected to the microcontroller to allow the user to read the power directly off the meter. The database displays values from the different meters and allows searching using SQL.
3. Hardware Specification
For hardware we’re using a Bird model 43 watt meter to measure the analog power. We used an amplifier to amplify the incoming signal and filter out noise. The signal is then sent to a microcontroller for processing and display on an LCD screen. Xbee modules are used for connection to a computer.
6
Low Cost 40Mhz RF Power Meter March 10, 2013
4. Software Specification
Requires .NETFramework,Version=v4.5 to be installed. This enables your software to communicate with the database. Ideally, the best way to get everything set up correctly is by installing Visual Studio 2013, which will automatically install the SQL environment.
5. Software Design
The graphic user looks like this:
We used Visual Basic to write our program. The software is able to connect and disconnect from the microcontroller via the Xbee connection. There are also options to save the data to a local drive or to a server.
7
Low Cost 40Mhz RF Power Meter March 10, 2013
6. Prototyping/testing
We had access to a testing facility at PowerFilm as well as resources at Iowa State to test our prototype. To generate the Radio Frequency signal, we used an RF power generator at PowerFilm. After we get the crucial voltage output from the meter, we are able to generate the same DC voltage at our ISU lab and use it to test our ADC function on the evaluation board
7. Circuit Design
There are 5 main parts to the circuit: Power -To power the circuit, we used a 5v, 800mA DC cell phone
charger that is cut at the end. A 5v linear regulator is used to filter out noise as well as a 5v-3.3v regulator to create 5v and 3.3v rails for use in the circuit.
MSP430G2553 - This is the microcontroller used in the circuit. The microcontroller drives an LCD, handles the analog to digital conversion for the signal from the bird meter, and sends the data via serial using the Xbee module.
LCD – Used to display the data produced in the microcontroller. Amplifier – A non-inverting opamp configuration was used in our
circuit. The signal from the power meter needs amplification to match the full range of the ADC in the microcontroller.
Xbee – Xbee modules are used for connection from the microcontroller and the computer.
8
Low Cost 40Mhz RF Power Meter March 10, 2013
Instruction Manual
Hardware Instructions:1. Connect the corresponding leads from the back of the analog to
the indicated “ADC” labeled on the board.
2. Connect the Rx, Positive, and ground of the Xbee module to the indicated “Xbee in” on the board.
3. Connect 5v DC source to the indicated “Supply” on the board.
Software Instructions:1. Download and install X-CTU from the official website
http://www.digi.com/support/productdetail?pid=3352&osvid=57&type=utilities
X-CTU is used for getting the Xbee module set up, you’ll need to configure both the receiver and transmitter.
2. Instructions to configure the Xbee moduleYou can configure the Xbee module according to the following website.http://www.faludi.com/itp_coursework/meshnetworking/XBee/XBee_program_Arduino_wireless.html
3. Connect the Xbee receiver to PC and the transmitter to microcontroller
4. Start the Graphic User Interface by either clicking the .exe file or run it in Visual Studio
5. Set up the directory of the database files to be put inModify the following string to your preferred directory
9
Low Cost 40Mhz RF Power Meter March 10, 2013
Dim Path As String = "C:\Users\AlfredX\Dropbox\school files\Graphic User Interface\Graphic User Interface\bin\Debug\"It will be modified further to pop up a window to let you select the directory
6. A window will pop up to let you input the Run numberA Run number is a code indicating device type.
7. Start logging data and showing visualized data
Once your port is shown in the top left corner box, you can click the Start button. The list box, shown below Available Ports, shows the data received.The chart on the right plots the data received.
10
Low Cost 40Mhz RF Power Meter March 10, 2013
8. Database
Clicking the Save button saves the data to the database file. View saved data by clicking View Database
You can easily view the data in the database.
The top navigation bar lets you modify the data.
A query function can be added later.
11
Low Cost 40Mhz RF Power Meter March 10, 2013
Team Members
Tyler ChristensenCircuits-Programming-CommunicationElectrical [email protected]
Jason Danielson Leader-SystemsElectrical [email protected].
Jiwei XiaCircuits-ProgrammingElectrical [email protected]
Yilun JiWebmasterElectrical [email protected]
Team Websitehttp://seniord.ece.iastate.edu/dec1304/
Team contact [email protected]
12