Tenma 72-14520 User manual

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Digital Phosphor Storage Oscilloscope
Model No. 72-14520, 72-14525,
72-14530 & 72-14535

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When using electrical appliances, basic safety precautions should always
be followed to reduce the risk of re, electric shock and injury to persons or
property.
Read all instructions before using the appliance and retain for future reference.
• This meter is designed to meet IEC61010-1, 61010-2-032, and 61010-2-033 in
Pollution Degree 2, Measurement Category (CAT II 150V when switched to 1X and
300V CAT II when switched to 10X) and double Insulation.
• Check that the voltage indicated on the rating plate corresponds with that of the
local network before connecting the product to the mains power supply.
• Do not operate this product with a damaged plug or cord, after a malfunction or
after being dropped or damaged in any way.
• Check the product before use for any damage. Should you notice any damage on
the cable or casing, do not use.
• This product contains no user-serviceable parts. All repairs should only be carried
out by a qualied engineer. Improper repairs may place the user at risk of harm.
• Take caution when voltages are above 60V DC and 30V ACrms.
• The earth probe must only be used to connect to ground, never connect to a
voltage source.
• This product must be earthed using the mains power cord ground connection.
• Do not disconnect from the mains supply and it’s ground connection when any item
is connected to this product for measurement.
• Children should be supervised to ensure that they do not play with the product.
• Always disconnect from the mains when the product is not in use or before
cleaning.
• Do not use the product for any purpose other than that for which it is designed.
• Do not operate or store in an environment of high humidity or where moisture may
enter the product as this can reduce insulation and lead to electric shock.
PRODUCT OVERVIEW
Main Features
• Two and four channels with HD colour 8” LCD display
• Real-time continuous hardware waveform recording and waveform analysis
• Multi‐waveform mathematical operation function
• Automatic measurement of 34 waveform parameters
• Edge, video, pulse width and advanced trigger functions
• Waveform capture rate of up to 50,000wfms/s
• Supports plug and play USB storage devices and communication with PC
• Unique waveform recording and replay function
WHAT’S INCLUDED
• Digital Oscilloscope Unit
• Mains power lead
• User Manual
• Communications software CD
• USB lead
• Selectable 1:1/10:1 passive probes
Optional accessories
• LAN port module

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CONTROLS AND CONNECTIONS
OPERATING PARAMETERS
• The oscilloscope also has high performance index and powerful functions required
for faster measurements.
• Faster signals can be observed with the oscilloscope via 1GS/s real‐time sampling.
• Powerful trigger and analysis ability make it easier to capture and analyse
waveforms.
• Clear LCD and mathematical operating functions make it easy to use to observe
and analyse signal problems in a faster and clearer way.
1. Screen display area
2. Copy/print screen
3. Multifunctional control
4. Function menu
5. Automatic setting
6. Run/stop
7. Single trigger control
8. All clear
9. Calibration and ground terminal
10. Trigger control area
11. Horizontal control area
12. Analogue channel inputs
13. Vertical control area
14. Control menu
15. USB HOST Interface
16. Power on/off
REAR PANEL
1. External trigger input
2. Pass/Fail output
3. USB Socket
4. LAN network
5. Safety Lock
6. AC Power Socket
7. Main power switch
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• Boot check
• Power on the unit at the rear followed by the soft power button on the front panel.
• The oscilloscope then run through a set on self test functions followed by the
display screen showing.
• Take the probe and connect its BNC header to the BNC terminal of the
oscilloscope. Connect the probe’s main alligator clip to the “Calibration terminal”
and the ground clip also connected to the “Ground terminal”.
OPERATION
AUTO SET WAVEFORM DISPLAY
Probe compensation
• Perform this adjustment when connecting the probes
to any input channel for the rst time or errors in the
measurement may result.
• Set the attenuation coefcient in the probe menu and the
switch on the probe to 10x
• Enable CH1 and press AUTO.
• Observe the shape of the displayed waveform.
• Adjust the variable capacitor on the probe with an insulated screwdriver until a
correct waveform is achieved.
• The oscilloscope features an AUTO SET function which automatically adjusts the
vertical deection factor, scanning time base and trigger mode based on the input
signal until the most appropriate waveform is displayed.
Using the AUTO SET function
• Connect the signal to be measured to the signal input channel.
• Press AUTO and the oscilloscope will adjust the vertical scale factor, timebase, and
trigger mode according to the input signals.
Calibration Terminal
Ground Terminal
Correct Compensation Under CompensationOver Compensation

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DISPLAY SETTING CONTROLS
Vertical control panel
• 1 2 3 4: open or close the four channels display. Model dependent.
• MATH: Open the mathematical operations menu for add, subtract,
multiply, divide, FFT, ltering, logic, and advanced operations.
• REF: Recall previously stored reference waveforms, can compare
currently measured waveform with reference waveforms.
• VERTICAL POSITION CONTROL: Used to adjust the vertical
position of the current channel waveform. Press this knob to return
the channel display back to the midpoint position.
• VERTICAL SCALE CONTROL: Used to adjust the vertical scale of
the current waveform. The vertical scale has 1, 2, and 5 steps.
• Pressing the button allows the vertical adjustment to switch between coarse and
ne adjustment mode.
Level (horizontal) control panel
• Displays window extension, independent timing, and holdoff time.
• HORIZONTAL POSITION CONTROL: Adjusts the horizontal position
of the current channel waveform. Press this control to return the
channel display back to the midpoint position.
• HORIZONTAL SCALE CONTROL: Used to adjust the vertical scale of
the current waveform. The vertical scale has 1, 2, and 5 steps.
• Pressing the SCALE button allows the vertical adjustment to switch
between main and extensible window mode.
Trigger system
• TRIGGER LEVEL CONTROL: Adjusts the currently selected trigger level.
Press the control to return the trigger level back to the midpoint position.
• TRIG MENU: Press to display the trigger menu.
• FORCE: Press to generate a trigger event once.
• HELP: Displays built-in help system.
Auto Setting
• When this key is pressed, the oscilloscope will automatically
adjust the vertical scale factor, timebase, and trigger mode
according to the input signals.
Run/Stop
• Press the key to “run” or “stop” sampling. RUN state is indicated by green
light. STOP state is indicated by red light.
Single
• Set to single trigger mode. After the trigger point the oscilloscope
will stop sampling.
Clear
• Clear all waveforms. If the oscilloscope is in the “RUN” state, it will
continue to display new waveforms. The screen will momentarily clear if
in “stop” state when “run” is pressed and sampling re-starts.
Screen Copy
• Copy the screen to a BMP format image and store it to USB device.

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Multi-purpose Control
• Press the DISPLAY button and press F3 or F4 to select the
brightness options, then use the control to adjust the brightness.
• Press the control to conrm the setting.
• During menu operations the control can be used to select various
sub menu options, then press it again to conrm selection.
Function Keys
• MEASURE: Measure setting menu: can set
measure source to all parameters, custom
parameters, perform measurement statistics,
select measurement indicators, etc.
• ACQUIRE: Sampling setting menu to set up
acquisition mode and storage.
• STORAGE: Storage interface can select different types of storage and waveform
settings, which can be stored internally or through USB device.
• CURSOR: Cursor measurement menu can measure waveform’s time and voltage
manually with cursor. Press F1 to turn on or off.
• DISPLAY: Select display settings, such as display type, format, duration, grid
brightness, and waveform brightness.
• UTILITY: The utility menu can choose between some less commonly used settings
such as self-calibration, system information, language, menu display, waveform
recording, pass test, square wave output, frequency meter, system upgrades, back-
light brightness, output, etc. using relevant function button.
• DEFAULT: Restore to factory default settings.
USER INTERFACE
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1. USB Device Identication: This icon will be displayed when an USB storage
device is connected.
2. Trigger Status Identication: Include TRIGED (has been triggered), AUTO,
READY, STOP, and ROLL (rolling)
3. Timing Scale: Indicates the amount of time represented by one square, which can
be adjusted by the horizontal scale control.
4. Sampling Rate/Acquisition Mode: Indicates the current sampling rate and storage
depth.
5. Horizontal Displacement: Shows the horizontal displacement, which can be
adjusted by turning the horizontal position control. Pressing the control returns the
displacement back to 0.
6. Trigger Status: Displays trigger source, type, slope, coupling, level, etc.
• TRIGGER SOURCE: There are seven states: CH1~CH4, AC Line, EXT, and EXT/5.
Note: CH1~CH4 will each be displayed a different trigger colour.
• TRIGGER TYPE: The types are edge, pulse width, video, slope, and advanced
trigger.
• TRIGGER SLOPE: The types are rising, falling, and rising/falling.
• TRIGGER COUPLING: The types are DC, AC, high frequency, low frequency and
noise.
• TRIGGER LEVEL: Indicates the current trigger level value, can be adjusted with the
trigger level control.
7. CH1 Vertical Identication: Displays CH1 activation state, channel coupling,
bandwidth limit, vertical prole, and probe attenuation coefcient.
• CHANNEL ACTIVATION STATE: When the background colour is consistent with
the channel colour, the channel is activated. Press CH1~CH4 to open/close the
corresponding channel.
• CHANNEL COUPLING: Includes DC, AC, and grounding.
• BANDWIDTH LIMITATION: When the bandwidth limit function is turned on, a BW
icon will appear in the display.
• VERTICAL PROFILE POSITION: When CH1 is activated, the vertical prole can be
adjusted with the vertical scale control.
• PROBE ATTENUATION FACTOR: Displays CH1 probe attenuation coefcient:
0.001X, 0.01X, 0.1X, 1X, 10X, 100X, and 1000X
8. CH2 Vertical Identication: Same as 7 but for CH2
9. CH3 Vertical Identication: Same as 7 but for CH3
10. CH4 Vertical Identication: Same as 7 but for CH4
11. Operation Menu: Displays the current operation menu. Use F1 ~ F5 to navigate
through menu contents
12. Analogue Channels: Displays CH1~CH4 waveforms with matching tag and
waveform colour.

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INSTRUMENT SETUP
Vertical system setup
• The 2 analogue channels are CH1 and CH2, and for 4 channel models the
channels are CH1 to CH4. Each channel should be set up individually.
• Press CH1 to CH4 and the system will display the operation menu for that channel.
• CH1~CH4 contains 3 states: open, activate, and shut down.
• Open: Allows the corresponding channel waveform to display on the screen.
• ACTIVATION: Only opened state can be activated. In the active state, the vertical
menu and the vertical control knobs (POSITION, SCALE) are for changing
activated channel setting. Any of the channels that have been opened but not
activated could be activated by the corresponding channel keys
• OFF: No waveform appears on the display.
Channel coupling setup
• If for example a signal is applied to CH1 which has a sine signal that contains DC
quantities.
• Press F1 to select AC and set up as AC coupling. Any DC quantities in the signal
are now intercepted.
Press F1 to select DC.
• Both AC and DC quantities of the signal being measured can now pass through.
• The waveform displays both AC and DC quantities of the signal.
Functions Menu Setup Notes
Coupling
AC Intercepts the DC quantities of the input signal.
DC Pass AC and DC quantities of input signal
GROUND Disconnect input signal
Bandwidth Limit On Limit bandwidth to 20MHz to reduce noise display.
Off Full bandwidth
Vertical Sensitivity
Coarse tune Coarse tune in steps of 1-2-5 to set up the
deection factor of the vertical system.
Fine tune Fine tune is further tuning within the coarse tune
set up to improve the vertical resolution.
Probe
1X, 10X,
100X and
1000X
Select either value based on the probe attenuation
factor to keep the vertical deection factor reading
correct.
Next Page Go to the second page of the channel menu
Invert On Waveform invert function on.
Off Normal waveform display.
Bias On Turns on bias function
Off Turns off the bias function
Bias Voltage Adjust with the multi purpose control, the bias
voltage is used to offset the DC voltage the signal
Return to Zero Returns the bias voltage back to 0V
Return Return to the rst page of the channel menu

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Channel bandwidth setup
• If for example a signal is applied to CH1 which is a pulse signal that contains high
frequency oscillation.
• Press CH1 to select Channel1.
• Press F2 to set the BANDWIDTH LIMIT OFF so it is set up as full bandwidth.
• The signal being measured can now pass through even if it contains high frequency
quantities.
• Press F2 to set BANDWIDTH LIMIT ON so that frequency quantities higher than
20MHz in the signal being measured will be limited.
Probe rate setup
• To match the probe attenuation factor setup, it is necessary to set up the probe
attenuation factor in the channel operation menu accordingly.
• For example when the probe attenuation factor is 10:1, set the probe attenuation
factor at 10X in the menu. This principle applies to other values to ensure the
voltage reading is correct.
• The coefcients can be set to 0.001X, 0.01X, 0.1X, 1X, 10X, 100X, and 1000X.
Waveform inversion (Reverse Phase)
• The displayed signal is inverted 180 degrees with respect to the ground level.
• The vertical identication will display a reverse phase logo ↓.
Vertical Volts/Div adjustment setup
• The VOLTS/DIV range of the vertical deection factor can be adjusted either in
coarse or ne tune mode.
• In COARSE TUNE the VOLTS/DIV range is 1mV/div~2V/div. Tuning is in steps of
1-2-5. For example: 10mV - >20mV - >50mV - >100mV.
• In FINE TUNE mode it adjusts in 1% of the current amplitude value steps.
For example: 10.00mV—>10.10mV—>10.20mV—>10.30mV.
• Press F1 to select GROUND.
Both AC and DC quantities of the signal being measured are now intercepted.
• The waveform is not displayed in this mode but the signal remains connected to the
channel circuit.

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Bias
• When the amplitude of the DC component in the signal is relatively large, waveform
observation could be very inconvenient.
• Using the bias function and the superposition of a -10V bias voltage can eliminate
the DC component of the waveform so the AC signal can be clearly observed.
Setting up the Trigger system
• Triggering decides when the oscilloscope collects data and displays waveforms.
Once the trigger is correctly set up, it can convert unstable display into signicant
waveforms.
• When beginning to collect data the oscilloscope rst collects sufcient data to draw
a waveform on the left of the triggering point.
• While waiting for the triggering condition to occur it will continuously collect data.
When sufcient data is acquired to draw a waveform on the right of the triggering
point.
Trigger Source - Trigger can be obtained from various sources: Input channel (CH1,
CH2, CH3 or CH4), external trigger (EXT, EXT/5) or Line A/C etc.
1. Input channel - the most common trigger source is input channel. The selected
trigger source can operate normally whether the input is displayed or not. Select
any one of the analogue signal input terminal CH1~CH4 on the front panel of the
oscilloscope as a trigger signal.
2. External trigger - Select the input Trig EXT from the back of the oscilloscope. For
example, the external clock input can be used on the Trig EXT terminal as a trigger
source. EXT signal trigger level ranges from -1.8V~ +1.8V can be set. The EXT/5
trigger signal divides the actual signal by 5, so the trigger level can be increased to
-9V ~ +9V.
3. AC Line - Power supply signal, used to observe the relationship between power
signals such as lighting equipment and power supply equipment, to obtain stability
in synchronization.
Trigger Mode - determines the action of the oscilloscope when there is no trigger. There
are three trigger modes - auto, normal and single.
1. Auto Trigger - samples the waveform data when there is no trigger signal input.
The scan base is shown on the display. When the trigger signal is generated it
automatically turns to trigger scan for signal synchronisation.
Note: when the time base of the scan waveform is set to 50ms/div or slower, the auto
mode allows no trigger signal.