in this chapter, the result discussion is drawn firstly which discusses if all the questions of this project are solved. Then, the method of this project is also discussed. Last, the conclusions and recommendations are depicted to organize the project conclusions and give advice to the further using and development of this device.
5.1 Result discussion
1. Result discussion of the main question:
The deliverables of this project is the EVA2 calibration device which can check if the EVA’s test tools meet their specifications and there also a software with GUIs designed to operate the device. Hence, the main question is solved.
2. Result discussion of the sub questions
• What are the specifications of each EVA2’s measurement tools?
The specifications of each EVA2’s measurement tool are depicted in the research proposal which are achieved by doing the research.
• What are the rough block designs for the calibration tasks?
The rough block designs for each calibration task are divided into two parts. The first part is the hardware integration design shown in the Components selection phase in each
subsystem result phase. The hardware integration designs are based on the requirements of each subsystem and the current situation of the EVA2 setup. The second part is the rough GUI designs which are the draft design for the final GUI design and are utilized to debug and modify to reach all the desired functions of GUIs.
• What are the suitable Printed Circuit Board (PCB) designs for each measurement tools’
calibration task?
The separate designs for each measurement tool are shown in the Subsystem integration phase which solve this sub question properly.
• What is the best design to combine each designed calibration device into one PCB board?
The main sheet of the PCB schematics designs is a suitable combination to integrate all designed calibration device into one PCB board. However, the only mistake is that when designing the schematic of the main sheet, the address of the third PCA9555 is wrong which is caused by the disconnection between VCC and one pin. Under such circumstances, it is required a wire to connect the pin with VCC manually and this problem was solved later on.
• What software with GUI could be designed to operate the calibration device and return the results?
39 The GUI design for the system and subsystems are shown in the Appendix VI and the
corresponding logic diagrams for programming are shown in the Appendix V. The GUIs can not only realize controlling the EVA2 calibration board but also can return the results of calibration actions.
• What kind of test can be done to make sure the designed calibration device’s testing results are equal to the valid calibrated equipment’s?
All the test plans for validating each subsystem are shown in the Appendix I. However, the test results cannot exactly equal to the desired results because of inevitable errors, for example, the electromagnetic interference between the hardware. Hence, if the test results are approximately equal to the desired results with a certain margin of error as shown in the Table below, then the tests are successful.
Table 5-1 Each subsystem's margin of errors Subsystem ADC calibration DAC
calibration
Input value =0V:
±0.002 V;
Input value ≠0V: 1%
3% 3% 10%
5.2 Method discussion
The V-model can fully lead the project into the efficient track to design a device which meets all the requirements from customers. It divides the project into several phases which ensures the designs and the implements came out systematically. Moreover, the validation phase and the test plan help to ensure the accuracy of the results and improve the quality of the final product.
5.3 Conclusions & recommendations
The whole project is focusing on solving the main question: What is the design of a calibration device which can check if the EVA’s test tools meet the specification, can be operated by a software and return the results via a graphical user interface (GUI)?
After solving each sub question, the answer to the main question would be:
A PCB board called EVA2 calibration device achieves all the functions with a GUI in the PC. The EVA2 calibration device is composed of six calibration parts, including ADC calibration, DAC calibration, PowerIO calibration, JTAG calibration, oscilloscope calibration and AFG calibration.
For the hardware part, all of them use MCUs to control the components, for example, the analog multiplexers and counters. The EVA2 calibration device communicates with the PC through the I2C communication bus via USB and the SPI to I2C bridge in the DAC modules. All the MCUs have their own address to be recognized by the PC. For the software part, the GUI designed with the Delphi can operate the EVA2 calibration board and help users to accomplish
40 the calibration actions. There are one main GUI and six sub GUIs which are corresponding to each calibration part. Each sub GUI can calibrate all the channels of each tools and can return the results clearly as symbols with different colors and return the exact test values through new windows to the users.
The EVA2 calibration device might require further development and the recommendations are listed below:
• The main sheet of the schematics design has a problem: the address pin (21) of the PCA9555 (U2) is disconnected with the VCC. And the problem has already been solved by connecting a wire. However, it is better to redesign the schematics of the device and rebuild a new board to avoid destroying the wire.
• For the oscillator and AFG calibration subsystem, the GUI can open the Picoscope software in the background and all the commands of the users can realize in the GUI instead of in the Picoscope software. Hence, it is better to utilize the driver for
Picoscope software to in the background which will make the software more intelligent and save users’ time.
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References
Analog Devices, I. (2002). AD5308/AD5318/AD5328 Data sheet. Retrieved from Analog Devices:
https://www.analog.com/media/en/technical-documentation/data-sheets/AD5308_5318_5328.pdf
Analog Devices, I. (2003). AD7927 Data sheet. Retrieved from Analog:
https://www.analog.com/media/en/technical-documentation/data-sheets/AD7927.pdf BEST, I. (2021). IPC-A-610 Training & Certification. Retrieved from Best:
https://www.solder.net/ipc-a-610-acceptability-of-electronics-assemblies/
elprocus. (2020). Know all about Darlington Transistor Pair. Retrieved from elprocus:
https://www.elprocus.com/darlington-transistor-pair-circuit-with-working/
Enterprises, L. (2018, April 27). What is IPC-A-610 J-STD-001 For Electronic Assembly? Retrieved from Levision Enterprises: https://blog.levisonenterprises.com/ipc-j-std-001
Eurocircuits. (2021). What is a PCB or Printed Circuit Board? Retrieved from Eurocircuits:
https://www.eurocircuits.com/pcb-printed-circuit-board/
Good Will Instrument Co., L. (n.d.). Arbitrary Function Generator AFG-2225 Datasheet. Retrieved from Gwinstek: https://www.gwinstek.com/en-global/products/downloadSeriesSpec/468
Gwinstek. (2020). AFG-2225 Dual-Channel Arbitrary Function Generator. Retrieved from Gwinstek:
https://www.gwinstek.com/en-global/products/detail/AFG-2225
Haboud, D. (2018, Janurary 26). Getting Started with PCB Design. Retrieved from Altium:
https://resources.altium.com/p/getting-started-pcb-design Hope, C. (2019, 11 16). GUI. Retrieved from Computer Hope:
https://www.computerhope.com/jargon/g/gui.htm Instruments, T. (2007). SN74LVC2T45.
Kumar, D. (2019, 5 21). Software Engineering | SDLC V-Model. Retrieved from GeeksforGeeks:
https://www.geeksforgeeks.org/software-engineering-sdlc-v-model/
Kwekkeboom, G. (2019). The engineer's guide to the V-model. Driewegen, the Netherlands: Physical copy by: Pumbo.nl.
Maximintegrated. (2021). MAX14757EUE+T Datasheet.
Nexperia. (2020, April 14). 74HC4066; 74HCT4066.
Nexperia. (2021). 74HC4067DB. Retrieved from Nexperia: https://www.nexperia.com/products/analog-logic-ics/i-o-expansion-logic/analog-switches/74HC4067DB.html
Nexpiria. (2017, September 26 ). 74HC4051; 74HCT4051.
2 NI. (2019, 3 5). PCB Design Fundamentals: Prototyping and the PCB Design Flow. Retrieved from NI:
https://www.ni.com/content/ni/locales/nl-nl/innovations/white-papers/10/pcb-design-fundamentals--prototyping-and-the-pcb-design-flow.html
NXP. (2017). PCA9555.
Pico®Technology. (n.d.). PicoScope®2000 series.
Pico®Technology. (n.d.). PicoScope®5000D Series.
Wikipedia. (2020, 9 15). Analog device. Retrieved from Wikipedia:
https://en.wikipedia.org/wiki/Analog_device
Wikipedia. (2020, 10 12). arbitrary waveform generator. Retrieved from Wikipedia:
https://en.wikipedia.org/wiki/Arbitrary_waveform_generator Zheng, Y. (2018). EVA checker. Nijmegen.
Zwam, J. v. (2017). EVA documentation-EVA_TMU_rev7. Nijmegen.
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