Automated Test & Measurement System for a Power Supply and Control Board

Junior-level students in the Electrical and Computer Engineering Technology program complete a 3-credit Measurements & Instrumentation course. There are three main sections of the course: (1) Programming applications using LabVIEW, (2) Data acquisition, sensors, and signal conditioning, and (3) Design of measurement systems. Weekly laboratory activities mirror the lecture materials. Part of the requirements in the course includes an end-of-semester team design project where one possible option is the design and implementation of an automated test & measurement system for a power supply and control board (PSCB). For this project, students design and build the PSCB to meet these requirements: one DC output voltage, one function generator output with user selectable waveform type (sinusoidal, triangular, square waveform) and user selectable amplitude and frequency adjustments, four simultaneous TTL outputs, and four simultaneous TTL inputs. The function generator is implemented using a Cypress Semiconductor Programmable System-On-Chip (PSoC) prototyping kit. Using a National Instruments data acquisition device with analog I/O and digital I/O capability, students design an automated test & measurement system for testing the PSCB. Software is implemented with a state machine using LabVIEW. The program provides instructions to the user, using pop-up windows and/or text indicators, during the test. The program also prompts the user for adjustments (pots, switches, etc.) during the test. Additionally, the program writes test data to a file on disk. The file contains the user name, time & date stamp, and the serial number of the PSCB. This paper provides a detailed listing of the engineering requirements for the project. For the software design, functional requirements and operating sequence are provided. A summary of the contents of student reference materials and the lab handout are also included. Assessment results showing grading statistics, lab report format, and grading rubric, are provided. Examples of student work are included, along with a project assessment. Recommendations are shown to help ensure student success on the project. Introduction to the Measurements and Instrumentation Course This is a required junior-level course for Electrical and Computer Engineering Technology students. The purpose of the course is several-fold: • Learn principles of LabVIEW programming. • Use LabVIEW to design software for programming PC-based data acquisition (DAQ) systems • Understand various sensors and design signal conditioning circuits to interface the sensors to DAQ systems • Integrate all of these components into the design of measurement systems This course is lab intensive and utilizes LabVIEW with a data acquisition (DAQ) device as a primary vehicle for the design of measurement systems1-3. The course is 3 credits and consists of 2 hours of lecture and 2 hours of lab per week. The lecture content of the course is divided into three areas: Programming applications using LabVIEW (5 weeks), Data acquisition, sensors, and signal conditioning (4 weeks), and Design of measurement systems (7 weeks). LabVIEW is a graphical programming environment that allows a developer access to a wide variety of I/O and sensor interfaces, perform mathematical analysis, and link all of these operations to custom designed “control panels” or user interfaces. The lab content of the course is designed to reinforce concepts discussed during lecture. Each lab is considered a project since it lists a series of engineering requirements and requires 2 weeks to complete. Each project is completed by a student team that consists of no more than 2 students (some students prefer to work by themselves), where students pick their team members at the beginning of the semester. For nearly all of the projects, students are expected to work outside of the scheduled lab time in order to complete the objectives. Grading for the project consists of 60% based on meeting all of the engineering requirements, 30% based on the content of the lab report, and 10% based on spelling, grammar, and writing style. There is a 5% reduction for late lab report submittals. A listing of the projects for the course is shown below. • Lab 1: Software-defined Calculator Project (2 weeks) • Lab 2: Thermocouple Project (2 weeks) • Lab 3: Waveform Generator Project (2 weeks) • Lab 4: Digital Voltmeter Project (2 weeks) • Lab 5: Digital Multimeter Project (2 weeks) • Lab 6: Temperature Measurement System Project (2 weeks) In addition to the six lab projects, a final project is required for the course. The students can work in teams of two, or if a student prefers to work individually, they are awarded an extra 10% to compensate for their extra time and effort. Three weeks of scheduled lab time are provided at the end of the semester for students to work on their project. Some possible options for the project include: • Design and implementation of an automated test & measurement system for a power supply and control board (PSCB). • Design of an elevator control system • Design of a conveyor control system • Joystick control of finch robot system The purpose of this paper is to describe the details about the automated test & measurement system project. This is a lab in which students use a PSoC 5LP board to generate a series of waveforms, and then use LabVIEW to design the automated test and measurement system. Students have previously used off-the-shelf function generator ICs, when they were readily available, to generate the waveforms.