Specifications

The AUTO button

One of the biggest time-saving features of a digital oscilloscope is the AUTO button 22. This button tells

the oscilloscope to measure the signals on channels 1 and 2 and display them appropriately. The scope

manual will tell you what signals the scope will be able to measure automatically (or some

experimentation with a function generator will show you). The 254xB scopes require a signal of 50 Hz

or greater, a duty cycle of greater than 0.5%, and an amplitude of at least 10 mVpp to successfully

display a signal using the AUTO button. Knowing your scope's auto measuring capabilities for different

types of waveforms may prove useful in future investigations.

The auto measurement feature is convenient to working engineers and technicians, but may not be

desirable in an educational environment -- the instructor might want the students to learn how to set a

scope up manually. In such cases, the 254xB scopes can have their auto measurement capability

turned off.

Because the AUTO button can be accidentally pressed, a nice feature is to have a menu item to restore

the previous settings. This provides a useful method of measuring a second signal: disconnect signal 1

from channel 1, connect signal 2 to channel 1, press the AUTO button, write down any relevant

measurements from the second signal (or store the waveform), reconnect signal 1 to channel 1, and

press the Undo Autoset menu button to restore the settings you had for signal 1.

Quick help

The 254xB oscilloscopes have a quick help system that provides descriptions of the functionality of

keys and menu selections. Press and hold the key down for one or more help screens describing the

topic. For example, holding down the AUTO button 22 provides the following information on two

screens:

Press this key to get best waveform display by setting vertical, horizontal and trigger controls

automatically. The setups are as follows:

• Display type: Main

• Coupling: DC or AC

• Acquisition mode: Normal

• Vertical scale: Adjust to applicable scale

• Vertical position: Adjust to middle

• Bandwidth limit: Off

• Digital filter: Off

• Invert: Off

• Trigger type: Edge

• Trigger source: Channel with active signal

• Trigger mode: Auto

• Trigger coupling: DC

• Trigger level: 50% amplitude level of the trigger source waveform

• Trig-offset: Reset delay time to zero

• Holdoff: Reset holdoff time to default 100 ns

This quick help feature can be invaluable to a new user to help them understand the various features of

the scope.

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