B+K precision 2540 User manual

User Manual
Digital Storage Oscilloscopes
Models 2534, 2540 & 2542
Version 1.02
GeneralSafetySummary
General Safety Summary
Review the following safety precautions to avoid injury and prevent
damage to this product or any products connected to it. To avoid potential
hazards, use this product only as specified.
Only qualified personnel should perform service procedures.
To Avoid Fire or Personal Injury
Use Proper Power Cord. Use only the power cord specified for this
product and certified for the country of use.
Connect and Disconnect Properly. Do not connect or disconnect probes
or test leads while they are connected to a voltage source.
Ground the Product. This product is grounded through the grounding
conductor of the power cord. To avoid electric shock, the grounding
conductor must be connected to earth ground. Before making connections
to the input or output terminals of the product, ensure that the product is
properly grounded.
Connect the Probe Properly. The probe ground lead is at ground
potential. Do not connect the ground lead to an elevated voltage.
Observe All Terminal Ratings. To avoid fire or shock hazard, observe
all ratings and marking on the product. Consult the product manual for
further ratings information before making connections to the product.
Do Not Operate Without Covers. Do not operate this product with
covers or panels removed.
Avoid Exposed Circuitry. Do not touch exposed connections and
components when power is present.
Do Not Operate With Suspected Failures. If you suspect there is
damage to this product, have it inspected by qualified service personnel.

GeneralSafetySummary
Do Not Operate in Wet/Damp Conditions.
Do Not Operate in an Explosive Atmosphere.
Keep Product Surfaces Clean and Dry.
Symbols and Terms on the Product.
Protective Ground (Earth) Terminal.
CAUTION. Refer to user manual. Caution indicates a hazard
to property including this product
GeneralSafetySummary

Contents
5
Contents
Contents ..........................................................................................5
1. Getting Started...............................................................7
Inspect package content......................................................7
Front Panel ............................................................................8
Rear panel ...........................................................................14
Interpreting the display.......................................................15
2. Basic Operation ...........................................................17
Probe Compensation .........................................................17
Using Autoset ......................................................................18
Vertical Controls..................................................................20
CH1, CH2 Menu..........................................................22
REF Function...............................................................39
Horizontal Controls .............................................................42
Trigger Controls ..................................................................55
ACQUIRE Menu..................................................................67
UTILITY Menu .....................................................................78
MEASURE Menu ................................................................91
SAVE/LOAD Menu ...........................................................106
CURSOR Menu.................................................................117
DISPLAY Menu .................................................................123
RUN Controls ....................................................................126
3. Application Examples................................................129
Make Simple Measurements ..........................................129
Contents
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6
Capture a Single-Shot Signal......................................... 131
Reduce the Random Noise on a Signal ....................... 133
Trigger on a Video Signal ............................................... 135
PASS/FAIL Measurement............................................... 138
Waveform Recorder ........................................................ 140
Cursor Measurements..................................................... 144
4. System Message and General Problems ............. 151
System Message.............................................................. 151
General Problems ............................................................ 154
5. Specifications and Characteristics ......................... 157
Characteristics.................................................................. 157
Appendix A: Service and Warranty Information .................. 165


Getting Started
7
1.Getting Started
Inspect package content
Inspect the shipping container for damage. If the shipping
container and/or packaging material are damaged, it should
be kept until the content of the shipment has been checked
for completeness and the oscilloscope has been checked
mechanically and electrically.
Verify that you received the following items:
zOscilloscope
zTwo high performance 150MHz oscilloscope probes
zPower cord
zUser Manual
zTest report
zComsoft Installation disk
zUSB data cable
If the content is incomplete or if there is any mechanical
damage or defect, please contact your authorized distributor.
Getting Started

8
Front Panel
This section provides an introduction to the front panel of the
model 2534 and 2540 series oscilloscopes. Generally, you
set up the front panel controls first and then make your
measurements.
The keys or knobs on the front panel bring up softkey menus
on the display that provide further access to the
oscilloscope’s features. The entry knob is usually used to
select or change values. Five softkeys are located along the
right side of the display screen.
The following figure shows the front panel of the 2534/2540
series oscilloscopes.
Front panel

Getting Started
9
1. PRINT key
Press this key to print the current display to a USB mass
storage device.
2. AUTO key
When you press the AUTO key, the oscilloscope will
quickly determine which channels are active and
automatically scale the display to show the signals on
these channels.
3. Entry knob
The Entry knob is used to select items from menus and
input values. Its function changes when a different menu
is displayed. The curved arrow symbol to the left of
the Entry knob lights up when the Entry knob is active
and can be used to select a value.
4. Utility and Save/Load Menu
UTILITY
Access the system utility functions, such as Language
Setup, I/O Setup, and Print Setup etc.
SAVE/LOAD
You can save your current setup and waveform data to
the oscilloscope’s internal memory or to a USB mass
storage device and retrieve the setup or waveform later.
5. Measure and Waveform Menu
MEASURE
Getting Started
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10
Perform automated measurements of waveform
parameters.
ACQUIRE
The ACQUIRE menu lets you set the oscilloscope to
acquire waveforms in Normal, Peak Detect, or Average
mode and lets you select Real Time or Equivalent
sampling.
CURSOR
Press the CURSOR key to activate the cursors for
making custom voltage or time measurements on scope
signals.
DISPLAY
You can change the appearance of waveforms and the
display screen, select the color schemes, and adjust the
contrast, etc.
6. RUN control keys
The RUN/STOP key will be green when the oscilloscope
is waiting for a trigger event. When the trigger mode is
set to Normal, the display will not update until a trigger
event occurs. If the trigger mode is set to Auto, the
oscilloscope looks for a trigger; if no trigger is found, it
will be triggered automatically and the input signals will
be displayed.

Getting Started
11
Press the RUN/STOP key again to stop acquiring data.
The RUN/STOP key will be red. Now you may examine
the acquired waveform by panning and zooming.
Press the SINGLE key to acquire a single waveform
trace. The key will remain orange until the oscilloscope is
triggered. After the trigger event, the waveform is
displayed and triggering is disabled until re-armed by
pressing the SINGLE key again.
7. Vertical controls
You can use the vertical position control knob to move
the waveforms up or down on the display. There is one
vertical position control knob for each channel.
You can press the channel key CH1 or CH2 to switch the
channel on or off or access the associated channel menu
via the softkeys. There is one channel on/off key for each
channel.
You can press the MATH key to access the FFT (Fast
Fourier Transform), multiply, subtract, and add functions.
You can press the REF key to save or load a reference
waveform from the internal memory or an external USB
mass storage device.
You can use the vertical scale control knob to change the
vertical scale of a waveform. The waveform display will
Getting Started

12
contract or expand relative to the ground reference level.
There is one vertical scale control knob for each channel.
8. Horizontal controls
When the oscilloscope is in run mode, the horizontal
position control knob lets you set the acquisition window
relative to the trigger point. When acquisition is stopped,
you can turn this knob to pan through the stored
waveform data horizontally. This lets you see the
captured waveform before or after the trigger.
Press the horizontal MENU key to access the menu
where you can activate a delayed sweep or select X-Y or
Roll modes.
Turn the horizontal sweep rate control knob to adjust the
sweep speed. This changes the time base on the
display. When adjusted after the waveform has been
acquired and the oscilloscope is stopped, this has the
effect of stretching or compressing the waveform
horizontally.
9. Trigger controls
These controls are used to control how the oscilloscope
triggers to capture waveforms.
10. Probe compensation terminals

Getting Started
13
Use these two probe compensation terminals to match
each probe’s characteristics to the oscilloscope channel
to which it is connected.
11. External trigger input
This is the external trigger input BNC connector.
12. Channel input BNC
This is the channel’s input BNC connector. Connect the
oscilloscope probe or BNC cable to the BNC Connector.
13. MENU On/Off key
Press this key to toggle the menu display on and off.
14. Softkeys
Five menu softkeys are used to select the control and
parameter setting functions. Each softkey has a label
along the right side of the screen.
15. Power switch
Press once to turn power on, press again to turn power
off.
16. LCD display
The 320*240 matrix (5.7 inch) LCD displays captured
waveforms, setup information, measurement results, and
softkeys for setting up parameters.
Getting Started
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14
Rear panel

Rear panel
1. Line input receptacle
AC power cord receptacle. Attach to an AC power line
with a safety ground.
2. USB connector
The USB device connector can be connected to a
computer.
3. Extension port
Connect optional extension communication modules.
Contact B&K Precision for availability.
21
3

Getting Started
15
Interpreting the display
The oscilloscope display contains channel acquisition
information, setup information, measurement results, and soft
keys for setting up measurement parameters.
Interpreting the display
1. Readout shows the real time clock.
2. The USB icon displays when a USB device is connected.
3. Acquisition status readout shows RUN, STOP, WAIT, or
ROLL.
4. The square brackets show the location of the current
display window within the recorded waveform. The
Getting Started

16
record line color corresponds to the selected waveform
color.
5. The trigger position icon shows the trigger location within
the record.
6. The trigger position icon shows the trigger location in the
current displayed waveforms.
7. This readout shows the frequency of the trigger signal.
8. The trigger status readout shows the trigger status.
9. These are soft keys which allow you to set up additional
parameters.
10. The display area contains the displayed waveforms,
channel identifiers, and trigger and ground level
indicators. The channel information is shown in the same
color as the channel’s waveform.
11. This readout shows the delay setting or the trigger
location within the record, trigger source, trigger type,
and trigger level.
12. The horizontal readout shows the Main or Delayed time
base setting.
13. The channel readouts show the scale factor, coupling,
bandwidth limit, digital filter, and invert status.
14. Waveform baseline icons show the zero-volt levels of the
waveforms. The icon colors correspond to the waveform
colors.

Basic Operation
17
2.Basic Operation
Probe Compensation
Perform this adjustment to match your probe to the input
channel. This should be done whenever you attach a passive
probe for the first time to any input channel. A poorly
compensated probe can introduce measurement errors.
1. Connect the oscilloscope probe to channel 1. Connect
the probe tip to the 3Vp-p@1kHz terminal and connect
the probe’s ground lead to the chassis ground terminal,
then press the AUTO key.
2. Use a nonmetallic tool to adjust the trimmer capacitor on
the probe for the flattest pulse possible. The trimmer
capacitor is located on the probe BNC connector.
Correctly compensated
Over compensated
Under compensated
Basic Operation
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18
3. Connect probes to all other oscilloscope channels.
Repeat the procedure for each channel. This matches
each probe to each channel.
Using Autoset
The 2534 & 2540 series digital storage oscilloscopes provide
the Autoset function which sets the vertical, horizontal, and
trigger controls automatically.
Autoset function finds, turns on, and scales any channel with
a repetitive waveform that has a frequency of at least 50 Hz,
a duty cycle greater than 0.5% and an amplitude of at least
10 mV peak-to-peak. Any channels that do not meet these
requirements are turned off.
When you are using more than one channel, the Autoset
function sets the vertical controls for each channel and uses
the lowest-numbered active channel to set the horizontal and
trigger controls.
To configure the oscilloscope quickly and automatically,
press the AUTO key to display the connected signals that are
active.
To configure the oscilloscope to display multiple cycles,
press the Multi-Cycle softkey in the AUTO menu.
To configure the oscilloscope to display a single cycle, press
the Single Cycle softkey in the AUTO menu.

Basic Operation
19
To undo the effects of Autoset, press the Undo Autoset
softkey in the AUTO menu before pressing any other key.
This is useful when you have unintentionally pressed the
AUTO key or do not like the settings Autoset has selected
and want to return to your previous settings.
Au
to set oscilloscope channel 1
Basic Operation
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20
Vertical Controls

Vertical controls
Vertical Position Control (CH1, CH2)
Turn the small vertical position knob above the channel key
to move the channel’s waveform and its ground level icon ( )
up or down on the display. The voltage value momentarily
displayed in the bottom left portion of the display represents

Basic Operation
21
the voltage difference between the vertical center of the
display and the ground level( ).
Press the small vertical position knob above the channel key
to bring the channel’s waveform and its ground level icon ( )
directly back to the vertical center of the display.
Channel key CH1, CH2, MATH, REF
Press the channel key from the front panel to display the
channel’s menu. Pressing it again turns the display of the
channel on or off. The channel is displayed when the key is
illuminated.
You must be viewing the menu for a channel before you can
turn it off. For example, if CH1 and CH2 are both displayed
and the CH2 menu is now displayed. In order to turn CH1 off,
you should press the CH1 key first and CH1 menu will be
displayed; then press CH1 key again to turn off CH1.
Vertical Scale Control (CH1, CH2)
Turn the large vertical scale knob below the channel key to
set the scale factor for the channel. The vertical scale knob
changes the channel scale in a 1-2-5 step sequence. The
scale factor value is displayed in the bottom left portion of the
display.
Press the large vertical scale knob to toggle between Fine
and Coarse. When fine is selected, you can change the
channel’s vertical sensitivity in smaller steps. This is useful
when you want to scale the displayed waveform to an exact
Basic Operation
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22
size. When coarse is selected, the vertical scale knob
changes the channel scale in a 1-2-5 step sequence.

CH1, CH2 Menu
Press the channel key CH1 to display the channel’s menu
and turn the display of the channel on.
Channel Coupling
Press the channel key CH1, then press the Coupling softkey
to select AC coupling mode.
AC coupling places a high pass filter in series with the input
waveform that blocks the DC component of the input signal.
AC coupling is useful for viewing waveforms with DC offsets.
AC Coupling

Basic Operation
23
Press the channel key CH1, then press the Coupling softkey
to select DC coupling mode.
DC coupling passes both AC and DC components of the
input signal. DC coupling is useful for viewing low frequency
waveforms that do not have large DC offsets.
DC Coupling
Basic Operation
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24
Press the channel key CH1, then press the Coupling softkey
to select GND coupling mode.
GND mode blocks both AC and DC components of the input
signal by grounding the channel amplifier’s input.
GND Coupling

Basic Operation
25
Bandwidth Limit
When Bandwidth limit is on, the maximum bandwidth for the
channel is approximately 20 MHz. For waveforms with
frequencies below this, turning bandwidth limit on removes
unwanted high frequency noise from the waveform. The
bandwidth limit also limits the trigger signal path’s bandwidth
of any channel that has BW Limit turned on.
Press the channel key CH1, then press the BW Limit softkey
to turn the bandwidth limit off for the selected channel 1. BW
Limit off mode passes both the high and low frequency
components.
BW Limit off
Basic Operation
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26
Press the channel key CH1, then press the BW Limit softkey
to turn the bandwidth limit on for the selected channel 1. BW
Limit on mode blocks the high frequency components over
20MHz.
BW Limit on

Basic Operation
27
Probe Attenuation Setting
Probes are available with various attenuation factors which
affect the vertical scale of the signal. You can manually select
the factor that matches the attenuation of your probe. This
allows you to see the correct measured values for
waveforms.
For example, to match a probe set to 1X connected to CH1,
press the channel key CH1, and then press the Probe
softkey and select 1X.
Set Probe Attenuation Factor to 1X
Basic Operation
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28
Digital Filter
Press the channel key CH1, then press the Digital Filter
softkey to display the FILTER-CH1 menu. Four kinds of filter
types are available:
zLow pass filter
zHigh pass filter
zBand pass filter
zNotch filter
Press the Upper Limit or Lower Limit softkey and then
adjust the Entry knob to set the high and low frequency
range for the filter.
Digital Filter is off

Basic Operation
29
Digital Filter is on
Basic Operation
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30
Vertical Scale
Turn the large vertical scale knob below the channel key to
set the scale factor for the channel. The channel scale factor
value is displayed in the bottom left portion of the display.
Press CH1More 1/2 Volts Scale to select Coarse or
Fine adjustment. You can also press the large vertical scale
knob to toggle between Coarse and Fine. When Coarse is
selected, the vertical scale knob changes the channel scale
in a 1-2-5 step sequence. When Fine is selected, the vertical
scale knob changes the channel scale using a smaller step
size.
Fine Vertical Scale

Basic Operation
31
Vertical Invert
Press CH1More 1/2 Invert to turn Invert on or off.
When Invert is turned on, the voltage values of the displayed
waveform are inverted. Invert affects how a channel is
displayed, but does not affect triggering. If the oscilloscope is
set to trigger on a rising edge, it remains set to trigger on a
same edge after the channel is inverted. If the signal is
represented as f(t), then inverting the signal displays –f(t).
Inverting a channel will also change the result of any function
selected in the MATH menu or any measurement.
Vertical Invert off
Basic Operation
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32
Vertical Invert on

Basic Operation
33
MATHFunctions
Dual Waveform Calculation
Press the MATH channel key to turn on the MATH menu
page1/2.
Softkey Options Description
A+B Add A and B
A - B Subtract B from A
A × B Multiply A by B
Operate
FFT Access FFT menu
CH1 Select CH1 as Source A
Source A CH2 Select CH2 as Source A
CH1 Select CH1 as Source B
Source B CH2 Select CH2 as Source B
ON Invert ON
Invert OFF Invert OFF
More 1/2 ---- Select page 2/2
Basic Operation
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34
Press the softkey More ½to display the MATH menu page
2/2.
Softkey Options Description
A+B Add A and B
A - B Subtract B from A
A × B Multiply A by B
Operate
FFT Access FFT menu
Vertical scale control
Vertical position control
Split
Screen
Split the display into Main
and Math sections
Display
Mode Full
Screen
Display Math waveform
in full screen
More 2/2 ---- Select page 1/2

Basic Operation
35
For example, we select the A+B math function, select CH1 as
the Source A, and select CH2 as the Source B, then we will
see the math waveform displayed in red as follows:
Math A+B
FFT Spectrum Analysis
You can use the FFT function to measure, for example, the
harmonic content and distortion in systems, to characterize
noise in DC power supplies, and to analyze vibration.
Basic Operation
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36
Press the MATH key to turn on the MATH menu page 1/2,
and then press the Operate softkey to select FFT. The FFT
menu page 1/2 will be displayed.
Softkey Options Description
A+B Add A and B
A - B Subtract B from A
A × B Multiply A by B
Operate
FFT Enter FFT menu
CH1 Select CH1 for FFT
Source CH2 Select CH2 for FFT
Hanning Use Hanning window
Hamming Use Hamming window
Blackman Use Blackman window
Flattop Use Flattop window
Window
Rectangular Use Rectangular
window
dBV RMS Vertical scale in dBV
RMS
Scale
V RMS Vertical scale in V RMS
More 1/2 ---- Select page 2/2

Basic Operation
37
Press the softkey More 1/2 to display the FFT menu page
2/2.
Softkey Options Description
A+B Add A and B
A - B Subtract B from A
A × B Multiply A by B
Operate
FFT Enter FFT menu
Vertical scale control
Vertical position control
Split
Screen
Split the display into
Main and Math sections
Display
Mode Full
Screen
Display Math waveform
in full screen
More 2/2 ---- Select page 1/2
Basic Operation
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38
For example, we select CH1 as the source for the FFT, select
the rectangular window, set the vertical scale to dBV RMS,
and then we will get an FFT waveform similar to the following
figure. We can also measure the amplitude and frequency of
FFT points with the manual cursors ( see chapter application
examples, example“measure Frequency and Amplitude of a
FFT waveform”)
FFT Spectrum Analysis

Basic Operation
39
REF Function
You might make measurement on a known good system,
save the result to internal memory or to a USB mass storage
device, then make the same measurement on a test system
and recall the reference waveform to see the difference.
Press the REF channel key to turn on the REF menu page
1/2.
Softkey Options Description
CH1 Save CH1 as reference
Source CH2 Save CH2 as reference
REF vertical scale control
REF vertical position control
ON REF invert ON
Invert OFF REF invert OFF
More
1/2 ---- Select page 2/2
Basic Operation
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40
Press the softkey More 1/2 to display REF menu page 2/2.
Press REF channel key to turn on the REF menu page 1/2
and load the latest saved reference waveform at the same
time from the internal memory.
You can use the horizontal position and scale control knob to
change the time base of the reference waveform.
Press or softkey and turn the Entry knob
to change the vertical scale or position of the reference
waveform.
Softkey Options Description
Internal
Storage
INTERNAL
menu
Save the reference
waveform to
internal memory.
External
Storage
EXTERNAL
menu
Save the reference
waveform to a USB
mass storage
device.
More
2/2 ---- Select page 1/2