Introduction: Guide to the Tektronix TBS 1042 Oscilloscope
This oscilloscope (here after referred to as "o-scope") is an excellent beginning o-scope which provides most of the basic functions needed for analyzing/trouble shooting circuits. This guide will document how to properly set up the o-scope, and safely use many of its features. To begin with, here is a summary of the operating requirements and capabilities of the o-scope and the probes:
Power supply required: 90-264 VACRMS, 45-66 Hz. North American wall power is 120V, 60 Hz.
Channels: 2
Bandwidth: 40MHz
Input capacitance: 20 pF
Sample rate: 500 MS/s ( 500 Megasamples/second, or 500X106 samples/second)
Here are the specifications from the manual about the probes for this o-scope. It works well with the Textronix TPP0101 and the TPP0201. Both are passive probes with an attenuation factor of 10X. The only difference between the probes is the bandwidth. The TPP0101 has a maximum bandwidth of 100 MHz, while the TPP0201 can measure up to 200 MHz.
Electrical and Mechanical Specifications
| Characteristic | TPP0101 | TPP0201 |
|---|---|---|
| Bandwidth | DC to 100MHz | DC to 200MHz |
| System attenuation accuracy | 10:1 ± 3.2% | 10:1 ± 3.2% |
| Compensation Range | 15 pF - 25 pF | 15 pF - 25 pF |
| System Input Resistance | 10 ΩM ± 1.5% | 10 ΩM ± 1.5% |
| System Input Capacitance | <12 pF | <12 pF |
| System Rise Time (typical) | <3.5 ns | <3.5 ns |
| Propagation Delay | ~6.1 ns | ~6.1 ns |
| Maximum Input Voltage | <300 VRMS CAT II | <300 VRMS CAT II |
| Cable Length | <1.3 m | <1.3 m |
| Probe Connection Interface | BNC | BNC |
Environmental Specifications
| Characteristic | Description |
|---|---|
| Operating Temperature | -10 ° C to +55 ° C (+14 ° F to +131 ° F) |
| Storage Temperature | -55 ° C to +71 ° C (-60 ° F to +160 ° F) |
| Operating Alitude | 3.0 km (10,000 ft) maximum |
| Storage Altitude | 12.2 km (40,000 ft) maximum |
Step 1: Guide Terminology
Some preliminary terms to get us started
Soft key: any of the keys to the right of the screen without permanent labels. The screen will display an appropriate label for the keys depending on the context.
CH1 button: the yellow button labeled with a 1
CH 2 button: the blue button labeled with a 2
Step / Step: The slash indicates a series of steps that build on one another
Step 2: Probe Setup
Turn the o-scope on. Wait for it to pass the self-check, then press any button to continue. Connect the probe to the BNC port of Channel 1 on the o-scope. Align the slots on the probe with the small posts on the o-scope port. Twist the probe connector to the right to lock it in place. (Picture 1)
Probe compensation involves turning a small screw attached to variable capacitor inside the probe. By turning the screw, you change the frequency response of the probe. It helps ensure the probe measures accurately. On the TPP0101 and TPP0201 probes, the screw is located on the BNC connector.
Connect the probe tip to the upper terminal that says Probe comp. Connect the alligator clip of the probe to the bottom terminal with the ground symbol next to it. See the second picture for clarification
Now we need to make sure the o-scope knows the attenuation of the probe. The attenuation factor helps limit the load on the circuit under test, but it also divides your signal by some factor. The standard for general probes is 10X or an attenuation factor of 10. To set the o-scope, press the CH 1 button / press the Probe 10X Attenuation soft key / press Voltage Attenuation soft key until 10x appears. Press Back soft key / Press the button labeled AutoSet (see the third picture)
You will see a square wave on the screen with a period of 1 kHz at about 5 V peak-to-peak at 1ms/division (1ms/Div) (see the fourth picture)
Now we can compensate! If the output from the probe looks like the fourth picture with flat topped square waves, the probe is properly attenuated. If the leading edge of the square wave is curved like the fifth picture, the probe needs to be compensated more. Turn the compensations screw until the square wave is flat. If the leading edge of the wave is peaked, the probe is over compensated. Turn the screw until the wave is flat. Usually it will not take much turning to properly compensate the probe.
Step 3: Self Calibration and Current Probe Setup
Self Calibration
The Self Calibration feature ensures your o-scope is measuring accurately. The routine should be performed after the scope has been turned on for about 20 minutes to ensure it has equalized to ambient temperature. The check should be performed if the ambient temperature changes by 5 °C (9 °F) or more.
Disconnect any probes from the inputs ports. Then, press Utility / Do Self Cal and follow the directions on the screen.
NOTE: You can skip the following section if you are using a regular probe.
From the manual:
Current probes provide a voltage signal proportional to the current. The o-scope needs to be set so it matches the scale of the probe. The default scale is 10 A/V (10 amps/volt)
For a probe connected to CH 1, push the yellow 1 button / Probe (to the right of the screen) / Current / Scale and select the appropriate value
Step 4: Vertical Controls
The controls on the left control CH 1, and the controls on the right control CH 2.
The Position knob moves the respective signal up or down
The Scale knob increases or decreases the vertical scale factor of the window. It ranges from 20 mV to 50 V (0.02 V - 50 V).
By pressing the Volts/Div soft key (shown in the third picture) you can select to have the Scale knob provide course or fine adjustments of the vertical scale (AKA the vertical Volts/Division). A division is one of the white dotted lines displayed on the screen. 5 Volts/Div means each horizontal line indicates a change of 5 V from the previous horizontal line. The horizontal line in the middle of the screen represents 0 V.
The CH 1 and CH 2 buttons toggle their respective channels on or off.
The Math button toggles the Math waveform. Once the Math button is pressed, you will be able to select mathematical operations to perform using the two waveforms such as addition, subtraction, and multiplication. These options can be selected using the soft key labeled Operation.
Step 5: Horizontal Controls
The Position knob controls the horizontal location of all waveforms: CH 1, CH 2, and Math
The Horiz Menu button displays the Horizontal Menu
The Set to Zero button returns the horizontal axis to 0
The Scale knob controls the horizontal time/division factor of the window. It can range from 5 ns to 50 s.
Step 6: Trigger Controls
The trigger controls are used to change where the o-scope thinks a waveform begins or ends. These controls are useful for helping the o-scope understand what it should look for to display a clear and informative picture.
Generally the o-scope will look for the rising or falling edge of a waveform to define the start or end of a wave. The rising and falling edges are labeled in the second picture.
The Level knob controls what voltage the o-scope will trigger at. The knob moves the trigger level up or down, raising or lowering the trigger voltage level. The level is indicated on the screen with a line, called the Cursor.
The Set to 50% button sets the trigger level to halfway between the minimum and maximum amplitudes of the waveform.
The Force Trig button forces the o-scope to finish acquiring a signal and determine a trigger point. It does not function if the o-scope has already acquired a signal.
While holding the Trig View button, you can view the trigger waveform in place of the CH 1 or CH 2 waveform. This is useful for determining how the trigger settings affect where the o-scope thinks the trigger point is. It's good for trouble shooting.
There is also a trigger input on the bottom next to the CH 1 and CH 2 inputs. The trigger input can be used to tell the o-scope when to look for the start of a new waveform.
Step 7: General and Menu Control Buttons
The last group of buttons perform most of the information gathering functions of the o-scope.
The Multipurpose knob is used to navigate through menus displayed on the screen. When the green LED next to the knob is illuminated, the knob can be used to select various options.
The AutoRange button attempts to scale the window view to fit the waveform from the CH 1 or CH 2 probes. Be careful, you may get strange results if the o-scope cannot determine how to properly scale the display window. AutoRange continues to scale the window to fit the waveform if the waveform changes drastically.
The Save/Recall button access the Save/Recall menu
The Measurements button displays the Measurements menu. This is useful if you wish to measure certain aspects of the waveform, such as amplitude, period, frequency, or phase shift between two signals.
The Acquire button displays the Acquire menu. In the menu you will find settings to change how the o-scope interprets the waveform being measured. More information can be found in the manual.
The Ref. button allows you access stored reference waveforms.
The Utility button accesses the Utility menu
The Cursor button accesses the Cursor menu. Cursors are vertical and horizontal lines that can only be moved when the Cursor menu is activated. They are moved using the knobs on the o-scope. There are Time cursors (vertical lines) and Amplitude cursors (horizontal lines) that are used to measure time and amplitude characteristics of the waveform.
The Display button accesses the Display menu.
The Help button accesses the Help menu, which is quite useful for learning about various functions.
The Default Setup button returns the o-scope to the factory setup. This is useful if you make a big mess of things.
The AutoSet button attempts to make an intelligent choice to best display the input waveform. It seems to take more liberties than AutoRange, which one can interpret as more chances of making a mess displaying the signal. It can be useful for finding evasive waveforms.
The Single button acquires a single waveform and stops.
The Run/Stop button toggles between acquiring and pausing acquisition of the input waveform.
The Save and Save/Print buttons are used to save data to a USB drive inserted in the front panel.
Step 8: Simple Measurement Excercise
This step provides an easy way to learn how the o-scope probe is used to measure circuit components. I used an Arduino as the signal source.
The code was very rudimentary, just enough to get a PWM signal from the board. I attached a jumper cable to Pin 11, and another to ground. Then I attached the probe as shown in the first picture. The code was:
const int SignalOut = 11;
void setup() {
pinMode(SignalOut, OUTPUT);
}
void loop() {
analogWrite(SignalOut, 200);
}
Any pin with PWM capabilities can be used (it has a ~ next to the pin number) and any ground on the Arduino should work. As for the number, it can range from 0-255. Try different values to see what they look like on the o-scope! The result from my Arduino is in the second picture.
Step 9: Go Measure Things!
Once the probes are compensated, it is fairly straight forward to use the o-scope to acquire data. The the probe tip attaches to the point you are trying to measure. The attachment point for the ground clip can vary depending on the circuit, but it generally attaches to the ground of the circuit.
This o-scope as a lot to offer, and it will serve you well.
A great resource for advanced usage is the online manual, found here:
http://www.giakova.com/siti/GIAKOVA/img/upload/Pro...
It covers many more topics in greater depth.
