Whether or not you simply acquired a brand new oscilloscope or simply received entry to a revered lab instrument that you’re unfamiliar with, there’s a studying curve related to utilizing the instrument. Having run a technical assist operation for a significant oscilloscope provider, I do know that almost all technical individuals don’t learn manuals. This text (shorter than the everyday consumer handbook) is meant to assist those that want to make use of the instrument instantly get the instrument up and operating.

The entrance panel

Oscilloscopes from completely different producers look completely different, however all of them have many widespread components. If the oscilloscope has a entrance panel, it can have fundamental controls for vertical, horizontal, and set off settings just like the instrument proven in Determine 1.

Determine 1 A typical oscilloscope entrance panel with controls for vertical, horizontal, and set off settings. Supply: Teledyne LeCroy

Many controls have alternate actions evoked by pushing or, in some instances, pulling the knob. These are usually marked on the panel.

Many oscilloscopes, like this one, use the Home windows working system and will be managed from the show utilizing a pointing gadget or a contact display screen. Be at liberty to make use of any interface that works for you.

Getting a waveform on the display screen

It’s essential to notice that digital oscilloscopes retain their final settings. In case you’re utilizing the oscilloscope for the primary time, it’s a wise observe to recall its default setting. This step ensures you’re ranging from a identified setting’s state. Some oscilloscopes, just like the one used right here, have a devoted button on the entrance panel; recalling the default setting can be carried out utilizing a pulldown menu (Determine 2).

Determine 2 Recalling the default setup of an oscilloscope locations the instrument in a identified operational state. Supply: Arthur Pini

Within the instance proven, the default setting is recalled from the “Recall Setup” dialog field utilizing the Recall Default button, highlighted in orange.

Auto Setup

Utilizing the oscilloscope’s “Auto Setup” function to acquire a waveform on the display screen from the default state is easy.

As a fundamental experiment, join channel 1 of the oscilloscope to the calibration sign on the oscilloscope’s entrance panel utilizing one of many high-impedance probes included with the oscilloscope. This calibration sign is a low-frequency sq. wave used to regulate the low-frequency compensation of the probe’s attenuator.

Press the oscilloscope’s Auto Setup button on the entrance panel or use the Vertical pulldown menu to pick out Auto Setup (Determine 3).

Determine 3 The “Auto Setup” is both a front-panel push button or a range on a pulldown menu, as proven right here. Supply: Arthur Pini

“Auto Setup” on this instrument scans all of the enter channels so as and configures the instrument primarily based on the primary sign it detects. Primarily based on the detected sign(s), the vertical scale (volts/div) and vertical offset are adjusted. The set off is about to an edge set off with a set off stage of fifty p.c of the amplitude of the primary sign discovered. The horizontal timebase (time/div) is about in order that at the least ten sign cycles are displayed on the show display screen.

Totally different oscilloscopes deal with this perform in a different way. In some, the sign should be related to channel 1. Different fashions, just like the one proven, will search by means of all of the channels and arrange the primary sign discovered. “Auto Setup” in all oscilloscopes ought to get you to a degree the place you’ve a waveform on the display screen.

The fundamental controls—vertical settings

The fundamental oscilloscope controls embody vertical, horizontal, or timebase and set off. In Determine 3, these seem, in that order from left to proper, as pull-down menus on the menu bar. These controls are duplicated on the entrance panel and grouped beneath the identical headings. Both of the management varieties can be utilized.

Vertical controls, both on the entrance panel or on the display screen, are used to arrange the person enter channels. Choosing a channel creates a dialog field for controlling the corresponding channel. The vertical channel controls embody vertical sensitivity (volts/div) and offset. The channel setup controls embody coupling, bandwidth, rescaling, and processing (Determine 4).

Determine 4 The vertical channel setup contains the principal controls, together with vertical scaling, offset, and coupling. Supply: Arthur Pini

The vertical scaling needs to be set in order that the waveform is as near full scale as potential to maximise the oscilloscope’s dynamic vary. This oscilloscope has a “Discover Scale” perform icon the channel setup, which is able to scale the vertical acquire and offset to get the waveform centered on the display screen with an inexpensive amplitude. It’s good observe to not overdrive the enter amplifier by having the waveform exceed the chosen full-scale voltage limits. Use the zoom show to broaden the hint for a more in-depth take a look at tiny options. The offset management facilities the waveform on the show. Coupling provides a alternative of a 50 Ω DC coupling or 1 MΩ enter termination and AC or DC coupling.

The opposite controls embody a choice of enter bandwidth limiting filters, the flexibility to rescale the voltage studying primarily based on the probe attenuation issue, and the flexibility to rescale the amplitude studying in a sensor or a probe’s items of measure (e.g., amperes for a present probe). Sign processing within the type of averaging or digital (noise) filtering will be utilized to enhance the signal-to-noise ratio of the acquired alerts.

Channel annotation containers, just like the one labeled C1 in Determine 4, present the vertical scale setting, offset, and coupling for channel 1. When the cursors are turned on, cursor amplitude readouts also can seem on this field.

Timebase settings

Choosing “Horizontal Settings” from the “Timebase” pull-down menu or utilizing the entrance panel horizontal controls adjusts the horizontal scaling and delay of the horizontal axis, the acquisition sampling modes, the acquisition reminiscence size, and the sampling fee (Determine 5).

Determine 5 The timebase setup controls the sampling mode, horizontal scale, time delay, and acquisition setup. Supply: Arthur Pini

The “Horizontal” controls concurrently have an effect on all of the enter channels. Typically, three normal sampling modes are real-time, sequence, and roll mode. Actual-time is the traditional default mode, sampling the enter sign on the sampling fee for the complete period set by the horizontal scale. Sequence mode breaks the acquisition reminiscence right into a user-set variety of segments and triggers and acquires a sign in every section earlier than displaying them. Sequence mode acquisitions present a minimal lifeless time between acquisitions. Roll mode is for lengthy acquisition occasions with low sampling charges. Information is written to the show as it’s acquired, producing a show that appears like a strip chart recorder.

The time per division (T/div) setting units the horizontal time scale. The acquisition period shall be ten occasions the T/div setting. The acquisition delay shifts the set off level on the show. The default delay is zero. Detrimental delays shift the hint to the left, and constructive delays shift it to the proper.

The “Most Pattern Factors” subject units the utmost size of the acquisition reminiscence. By choosing “Set Most Reminiscence”, the reminiscence size varies because the T/div setting is modified till the utmost reminiscence is allotted. Past that time, rising the T/div will trigger the sampling fee to drop. Mainly, the time period of the acquisition is the same as the variety of samples within the reminiscence divided by the sampling fee. If the mounted sampling fee mode is chosen, the oscilloscope sampling fee will stay on the user-entered sampling fee because the T/div setting modifications. The T/div setting shall be restricted to settings suitable with the chosen sampling fee.

The pattern fee additionally impacts the span of the quick Fourier remodel (FFT) math operation, whereas the time period of the acquisition impacts its frequency decision.

This oscilloscope permits the consumer to pick out the variety of energetic channels. Observe that the reminiscence is shared among the many energetic channels.   

The “Navigation Reference” setting controls how the oscilloscope behaves once you alter T/div. The centered (50%) choice retains the present middle time level mounted, and different occasions transfer concerning the middle as T/div modifications. With this setting, the set off level might transfer off the grid as the size modifications. The “Lock to Set off” setting holds the set off level location mounted. The set off occasion stays in place as T/div modifications, whereas different occasions transfer concerning the set off location.

Fundamental set off settings

Oscilloscopes require a set off, often derived from or synchronous with the acquired waveform. The perform of the set off is to permit the acquired waveform to be displayed stably. The set off setup, both on the entrance panel or utilizing the “Set off” pulldown supplies entry to the set off setup dialog field (Determine 6).

Determine 6 The fundamental setup for an edge set off will permit the acquired waveform to be displayed stably. Supply: Arthur Pini

The sting set off is the standard default set off sort. In edge set off, the scope is triggered when the supply hint crosses the set off threshold voltage stage with the user-specified constructive or adverse slope. Set off sources will be any enter channel, or an exterior set off utilized to the EXT. enter. Edge set off is essentially the most generally used set off methodology and is chosen within the determine. The present scope settings proven use channel 1 because the set off supply. The set off is DC coupled with a set off threshold stage of nominally 500 millivolts (mV) and a constructive slope. Observe the “Discover Degree” button within the “Degree” subject will robotically discover the set off stage of the supply sign. The set off annotation field on the proper aspect of the display screen summarizes chosen set off settings.

The set off mode, which will be cease, automated (auto), regular, or single, is chosen from the set off pulldown menu. The set off mode determines how typically the instrument acquires a sign. The default set off mode is auto; on this mode, if a set off occasion doesn’t happen inside a preset time interval, one shall be compelled. This ensures that one thing shall be displayed. Regular set off mode arms the oscilloscope for a set off. When the set off occasion happens, it acquires a hint which is then displayed. After the acquisition is full, the set off robotically re-arms the instrument for the subsequent set off. Traces are displayed repeatedly because the set off occasions happen. If there are not any set off occasions, acquisitions cease till one happens.

In single mode, the consumer arms the set off manually. The oscilloscope waits till the set off occasion happens and makes one acquisition, which is displayed. It then stops till it’s once more re-armed. If a sound set off doesn’t happen, invoking Single a second time will drive a set off and show the acquisition. Cease mode ceases acquisitions till one of many different three modes is evoked. Different, extra complicated triggers can be found for extra complicated triggering necessities; nonetheless, they’re past the scope of this text.

Show

The oscilloscope show is managed from the show pull-down menu. The kind of show will be chosen from the pull-down, or the “Show Setup” will be opened (Determine 7).

Determine 7 “Show Setup” permits for the choice of the variety of grids and different display-related settings. This instance reveals the choice of a quad grid with 4 traces. Supply: Arthur Pini

This oscilloscope permits the consumer to pick out the variety of displayed grids. There may be additionally an “Auto Grid” choice, which activates a brand new grid when every hint is activated. A number of traces will be situated in every grid, permitting comparability of the waveforms. Having a single hint in every grid supplies an unimpeded view whereas sustaining the total dynamic vary of the acquisition. Along with regular amplitude versus time shows, the “Show Setup” contains cross plots of two traces producing an X-Y plot.

Show expansion-zoom

Zoom magnifies the view of a hint horizontally and vertically. The normal methodology to leverage the zoom features makes use of the pull-down “Math” menu to open “Zoom Setup” as proven in Determine 8.

Determine 8 Zoom traces will be turned on utilizing the Zoom Setup beneath the Math pull-down menu. Supply: Arthur Pini

Many oscilloscopes have a “Zoom” button on the entrance panel to open a zoom hint for every displayed waveform. Oscilloscopes with contact screens assist drop and drag zoom. Contact the hint close to the realm to be expanded after which drag the finger diagonally. A field shall be displayed; proceed dragging your finger till the field encloses the realm to be expanded. Take away the finger, and the zoom hint will be chosen to indicate the expanded waveform.

A fast begin information

This could get you began. Most Home windows-based oscilloscopes have built-in assist screens which may be context-sensitive and supply useful details about settings. In case you get caught, contact the producer’s customer support line; they are going to get you going shortly. If all else fails, contemplate studying the handbook.

Arthur Pini is a technical assist specialist and electrical engineer with over 50 years of expertise in electronics check and measurement.

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