Printing:

Sea-Bird Test Set _DOSTS-1000Michelle L Emmons, Steven Gaston & Colin Stefishen | Corporate Mentor: Vladic Simontov | Faculty Mentor: Dr. Eric Sortomme |University of Washington Bothell

Project OverviewThe objective of this project is to design and prototype an automated test

bench for both the Sea-Bird Electronics SBE 43 and SBE 43F Dissolved

Oxygen sensors. The current need for this test bench is to minimize testing

time for technicians and to overall streamline the testing process. The

utilization of the proposed test set will be used in the manufacturing process

for final confidence checks before customer distribution. In addition the use

of the test set will lead to shorter turnover times for customers needing

maintenance and repairs resulting in lower labor-hour cost.

Acting as an Engineering Consultant team for the customer Sea-Bird

Electronics our team designed and prototyped the Dissolved Oxygen Sensor

Test Set-1000 (DOSTS-1000) from start to finish. The project was

accomplished through circuit design, PCB development, along with

computer programing the firmware. The project final deliverables include the

prototype and final DOSTS-1000 hardware, software and all technical

documentation.

Hardware Flowchart Design Concept

PCB Design Layout

Software Flowchart

Design

• Driven by isolated circuitry

• Main driving factor for the design

• SBE 43 and SBE 43F have circuitry

that needs to be isolated from ground

• Circuit design split between isolated

and non-isolated grounds

• Design split into main 4 parts

• Signal Conditioning

• Retrieval of analog signals from

test probes

• Converts analog signals to a range

that microcontroller can handle

• Capacitor/Resistor Selector

• Bank of capacitors and resistors

• Different combinations of are

selected based on test parameters

• Power Supplies

• Supplies power to entire circuit and

oxygen sensors

• Microcontroller

• Controls when and what signals are

to be measured

• Measures analog signals with ADC

and frequency counter

• Communicates with PC

PCB consists of 4 different layers and has an overall size of 9.5" x 5.5"

Hardware process for SBE 43 & SBE 43F automated board test

Above: Test set positioned in enclosure

Left: Test set PCB with all components mounted

Simplified Software Flow Chart shows the Logic of Firmware design. Firmware Tests are initiated by

receiving set strings from UART sent by User Interface. Depending on the test MUX Selection,

Capacitor Selection, and Resistor Selection will change. Firmware then reads the voltage or frequency

dependent upon test and adjusts to readable values. Then the results are sent back to the User

interface by UART communication.