ProbeScope V3.0 for Windows/DOS (220-0310) Operation - Part 1 Faxback Doc. # 33356 USING THE SOFTWARE If all you want to do is make a quick and basic signal detection or AC/DC voltage measurement, you can simply use the ProbeScope's display. But, if you want to make a more detailed determination of a measured signal (such as a frequency, signal amplitude, phase shifting, DC biasing, etc.), you need to use the ProbeScope's software to display the measurements on your computer's monitor. To use the ProbeScope with your computer: If you are using MS-Windows: a. Double click the RADIOSHACK PROBESCOPE Program Group. b. Then double click the RADIOSHACK PROBESCOPE icon. If you are using MS-DOS: a. Type cd c:\proscope then press ENTER to enter the ProbeScope directory. b. Type scopedos.exe to select the ProbeScope software. c. Press ENTER to start the ProbeScope software. NOTE: The instructions on the rest of this owner's manual are specific to using MS-Windows, but they generally apply also to MS-DOS. USING THE TOOL BAR After you start the ProbeScope software, these icons appear on your monitor's display. (You can also access these functions using the provided keyboard shortcuts.) Open Icon - Opens an existing ProbeScope document (Ctrl-O) Save Icon - Saves the active document (Ctrl-S) Text Icon - Enters comments about the current ProbeScope document (Ctrl-C) Grid Icon - Shows and hides the oscilloscope screen's grid (Ctrl-G) Vert Icon - Shows and hides the vertical cursors (Ctrl-V) Horiz Icon - Shows and hides the horizontal cursors (Ctrl-H) Trig. Lv Icon - Shows and hides the trigger level line (Ctrl-L) NOTE: You can select this mode only when the TRIGGER mode is set to +/- INTERN or +/- EXTERN. Osc. Hold Icon - Freezes the measured signal on the oscilloscope display (Ctrl-I) Time Freq Icon - Switches between seconds and Hertz for the measured signal (Ctrl-U) NOTE: You can use this mode only when the vertical cursors appear on the oscilloscope display Print Icon - Calls up the print dialog menu (Ctrl-P) DVM Icon - Turns on and off the Digital Voltmeter (DVM) function (Ctrl-D) DVM Hold Icon - Freezes the displayed DVM measured value (Ctrl-A) NOTE: You can use this mode only when the DVM function is selected. SETTING THE PROBESCOPE 1. Select and set the desired modes: Press the menu button to display the available modes shown below. Press the select button to set the desired option in each of the available modes. MODE OPTIONS Timebase 50 ns 0.5 us 0.1 ms 100 ns 1 us 0.5 ms 5 us 1 ms 10 us 50 us Trigger Source AUTO + INTERN - INTERN + EXTERN - EXTERN Backlight ON OFF Function SCOPE DVM Trigger Level +/- 0.1V +/- 1V +/- 10V +/- INTERN +/- 0.3V +/- 3V +/- 30V +/- EXTERN +/- 0.5V +/- 5V +/- 50V Trigger Mode SINGLE RUN NOTES: A trigger is a designated pulse or signal that, when received, initiates conduction of a signal to be monitored or measured. These are the five selectable trigger levels: AUTO: The ProbeScope continuously triggers and records signals each time a trigger occurs regardless of its level (higher, lower, or equal to the incoming signal). If you set the input coupling switch to GND, the ProbeScope automatically sets the trigger to AUTO. + INTERN: The ProbeScope records signals only when the defined trigger event occurs. The signal is recorded when the trigger level is equal to the incoming signal and the signal is rising. - INTERN: The ProbeScope records signals only when the defined trigger event occurs. The signal is recorded when the trigger level is equal to the incoming signal and the signal is falling. + EXTERN: The ProbeScope records signals only when the defined trigger event occurs. The signal is recorded when the trigger level is equal to the signal present at the external trigger plug and the signal is rising. - EXTERN: The ProbeScope records signals only when the defined trigger event occurs. The signal is recorded when the trigger level is equal to the signal present at the external trigger plug and the signal is falling. These are the two available trigger modes: RUN: The probe records a new signal every time the defined trigger event occurs. Use this mode to measure or monitor a continuously running signal. SINGLE: The probe records a new signal each time you press the select button and the defined trigger event occurs. Use this mode to measure or monitor a signal that occurs only once, such as the noise heard when you turn on an electronic device. 2. Set the input coupling selector to the desired AC, DC, or GND setting. The actual setting appears on your computer's monitor. NOTES: In most cases, the AC component of a waveform can be measured with the input coupling selector in either the AC or DC position. However, in certain applications you might need to use the AC position to prevent the DC component of a waveform from deflecting the trace off the screen. To prevent inaccuracies, use the DC position when you make low- frequency measurements. When you set the input coupling selector to GND, the ProbeScope automatically resets the trigger mode to AUTO. 3. If you know the level of the signal to be measured, set the input voltage selector to the appropriate input range. INPUT VOLTAGE SWITCH POSITION VALUES TO BE MEASURED 1 V 0.00 - 1.00 V 10 V 0.0 - 10.0 V 100 V 0 - 100.0 V USING THE OSCILLOSCOPE The following applications describe how to make basic waveform measurements with the ProbeScope. These applications are not described in detail, but are designed to familiarize you with basic oscilloscope operating techniques. CAUTIONS: Never try to measure an AC peak-to-peak or a DC voltage the exceeds 100 volts. If you are not sure of what the measured signal level is, always start with the highest range. ESTABLISHING THE SCREEN'S VERTICAL DEFLECTION FACTOR When a measured signal appears on the oscilloscope's screen, you can use the grid overlay to measure the vertical displacement, then multiply this displacement by the deflection factor of the oscilloscope's screen. The result is the actual voltage. To do this accurately, you must first establish the screen's vertical deflection factor. 1. Click on the grid icon so the screen's grid overlay appears. 2. Divide the input voltage selector setting (1, 10, or 100) by 4 (the number of vertical squares on the screen's grid overlay). The result is the screen's vertical deflection factor. For example, if the input voltage selector is set to 10, and you divide 10 by 4, then the screen's vertical deflection factor is 2.5 volts/square. Therefore, if a measured signal is about 3 squares high, then the signal is estimated to be about 7.5 volts (3 x 2.5 = 7.5). NOTES: The screen's deflection factor applies only to the oscilloscope screen on the computer's monitor, and does not apply to the display on the ProbeScope. The grid overlay is not necessary if you want only to detect a signal but do not need to calculate voltage or frequency. The grid is necessary in order to calculate voltage, frequency, or both without using the cursors. DC COMPONENT VOLTAGE MEASUREMENTS In oscilloscope measurements, the DC component of a waveform is usually measured in terms of its DC flatline or AC average displacement above or below a reference line. The maximum DC voltage measurement you can make is determined by the positions of the input voltage selector and the zero line. For example, if the input voltage selector is set to 10 and the zero line is set at the middle position, the maximum measurement is +/- 5 Volts. Follow these steps to measure a DC voltage deflection. 1. Click on the horizontal cursor icon to display the horizontal cursors. 2. Connect the GROUND (0 volts) wire to the signal source's ground or reference level. 3. Set the input voltage selector to the desired position (1, 10, or 100) and the input coupling switch set to GND. 4. Use the zero line adjustment to position the zero reference line: On the bottom line of the grid overlay to get the maximum positive (+) measurement On the top line of the grid overlay to get the maximum negative (-) measurement. NOTE: The position on the grid overlay depends on the input signal's polarity and amplitude, but should be chosen so the trace lies along one of the major grid overlay's divisions. If the trace is widened by stray interference, ground the probe body near the point being measured. The trace position is the voltage reference line and all voltage measurements are read in respect to this line. (Do not adjust the vertical positioning control after the reference is established.) 5. If it was necessary to ground the tip (see Step 1 note), remove the tip from the ground or reference voltage. This readies the tip so you can use it to make a measurement. 6. Set the input coupling selector to DC. 7. Apply the probe tip to the signal source then click on the oscilloscope hold icon. 8. If measuring a pure DC signal, calculate the flatline's vertical distance from the zero reference line as follows: a. Set the computer's mouse cursor directly over the oscilloscope's screens' upper horizontal cursor until the cursor's shape changes to a cross. b. While you press and hold the left mouse button, move the mouse up or down until the screen's upper horizontal cursor is superimposed directly on the DC signal's flat-line waveform. The /\ VOLT: box shows the actual DC signal level. NOTE: If the /\ VOLT: box does not appear on the monitor, click on the DVM icon. If measuring the DC component of an AC signal, calculate the waveform's average vertical distance from the zero reference line as follows: NOTE: The average level of a pure sinusoidal, square, or triangular waveform is the midpoint between the positive and negative signal peaks. a. Place the mouse cursor directly over the oscilloscope screen's lower horizontal cursor until the cursor's shape changes to a cross. b. While you press and hold the left mouse button, move the mouse up or down until the screen's lower horizontal cursor is superimposed directly on the reference line. c. Place the mouse cursor directly over the oscilloscope screen's upper horizontal cursor until the cursor's shape changes to a cross. d. While you press and hold the left mouse button, move the mouse up or down until the screen's upper horizontal cursor is superimposed directly on the AC signal's midpoint between the positive and negative signal peaks. The /\ Volt: box shows the actual signal level of the DC component of an AC signal. NOTE: If the /\ VOLT: box does not appear on the monitor, click on the DVM icon. NOTE: You can also calculate the approximate voltage level by multiplying the approximate distance by the deflection factor. AC COMPONENT VOLTAGE MEASUREMENTS In oscilloscope measurements, the AC component of a waveform is usually measured in terms of its peak-to-peak value. You can easily make this type of measurement by using the grid overlay on the oscilloscope screen to measure the vertical distance between peaks and multiplying this distance by the oscilloscope screen's deflection factor. The result is the actual peak-to-peak voltage. Follow these steps to measure a waveform's peak-to-peak AC component. CAUTION: To avoid an overload when measuring AC, make sure the zero line is centered vertically on the grid overlay. 1. Set the input coupling to GND. 2. Rotate ZERO LEVEL until the zero reference line is centered vertically on the grid overlay. NOTE: If the trace is widened by stray interference, ground the probe body near the point begin measured. The trace position is the voltage reference line and all voltage measurements are read in respect to this line. (Do not adjust the vertical positioning control after the reference is established.) 3. If it was necessary to ground the tip (see Step 2 note), remove the tip from the ground or reference voltage. This readies the tip so you can use it to make a measurement. 4. Set the input coupling switch to AC. 5. Connect the GROUND (0 volt) wire to the signal source's ground or reference level. 6. Click on the horizontal cursor icon to display the horizontal cursors. 7. Apply the probe tip to the signal source then click on the oscilloscope hold icon. 8. Measure the vertical distance between the positive and negative peaks as follows: a. Place the mouse cursor directly over the oscilloscope screen's upper horizontal cursor. The cursor's shape changes to a cross. b. While you press and hold the left mouse button, move the mouse up or down until the screen's upper horizontal cursor touches the top of the signal peaks. c. Place the mouse cursor directly over the oscilloscope screen's lower horizontal cursor. The cursor's shape changes to a cross. d. While you press and hold the left mouse button, move the mouse up or down until the screen's upper horizontal cursor touches the bottom of the signal peaks. The /\ VOLT: box shows the actual AC peak-to-peak voltage (Vp-p) level. NOTES: If the /\ VOLT: box does not appear on the monitor, click on the DVM icon. You can also calculate the approximate voltage level by multiplying the approximate distance by the deflection factor. This technique can also be used to make measurements between two other points on the waveform. To accurately measure an AC peak-to-peak voltage, you must have at least two complete cycles of a waveform on the display. (yo/all-06/13/96)