Introduction to benchtop equipment and data acquisition

Introduction:

Many sensors produce analog (continuous) electrical signals. Once recorded, these signals are scaled todetermine the magnitude of the physical phenomenon. In this lab, you will learn about some common methods for recording anddisplaying voltage signals. Your focus will not be on any particular sensing technology. In the process of performing the labexercises, you will learn about hardware and software that you will use throughout the semester.

Teaching objectives:

• Learn to use a function generator to produce a variety of voltage signals.
• Become familiar with an oscilloscope and use it to record and analyze voltage signals.
• Become familiar with the lab PCs and PC-based data acquisition hardware.
• Learn how to write a simple LabVIEW VI to read a voltage signal and write data to a file.

Procedure:

Part 1: creating a signal with the function generator

Throughout this lab you’ll be asked to create different signals with the function generator. The functiongenerator at your workstation. Can create periodic square waves, sine waves and triangle waves. These waveforms can be injected intoa circuit under test and analyzed as the waveform progresses to confirm the proper operation of the device or to pinpoint a fault.Try to be accurate, but don’t waste a lot of time trying to get the“exact”frequency or voltage levels listed. The purpose of this lab does not depend on meeting exact values; rather, this lab is tohelp you become familiar with how the signal characteristics can be manipulated.

1. Turn on the oscilloscope and the function generator.

2. Use the frequency range buttons along the top of the function generator to produce a sine wave with afrequency in the range of 200 to 500 Hz.

3. Use the frequency knob (bottom left) to adjust the frequency.

4. Adjust the signal amplitude and DC offset.

Press the Display Select button next to the LCD readout.

Turn the appropriate knobs located on the right side of the function generator (above the BNCconnector).

5. Using a BNC cable, connect the MAIN OUT of the function generator to CH 1 of the oscilloscope.

6. Use the CH 1 and CH 2 buttons on the o-scope to turn the channels On or Off (e.g. to turn off CH 2,press CH 2 and then press OFF).

7. Push the AUTOSET button. This will set the triggering, horizontal and vertical so that the signal is displayednicely on the screen.

Part 2: analyzing a signal with an oscilloscope

The digital oscilloscope (o-scope) is used for viewing voltage signals that change with time. The o-scope measuresvoltage and displays thousands of samples over time. It is easier to visualize the characteristics of a signal with an oscilloscopethan with a digital multimeter.