VOLTCRAFT SL-451 User manual




 G

1. Introduction ................................................................................................................................. 25
2. Intended Use .............................................................................................................................. 26
3. Delivery content .......................................................................................................................... 27
4. Symbol explanation .................................................................................................................... 27
5. Safety instructions ...................................................................................................................... 27
6. Operating elements .................................................................................................................... 30
7. Software installation ................................................................................................................... 32
8. Initial operation ........................................................................................................................... 32
9. Basic setup setting ..................................................................................................................... 33
10. Device functions ......................................................................................................................... 35
11. Carrying out a measurement ...................................................................................................... 37
12. Data logger ................................................................................................................................. 39
13. Data transmission ....................................................................................................................... 40
14. Analog signal output ................................................................................................................... 40
15. Maintenance and cleaning ......................................................................................................... 41
16. Troubleshooting .......................................................................................................................... 41
17. Disposal ...................................................................................................................................... 42
18. Technical data ............................................................................................................................ 42


 
Dear Customer,
In purchasing this Voltcraft® product, you have made a very good decision for which we would like
to thank you.
Voltcraft® - In the eld of measuring, charging and network technology, this name stands for
high-quality products which perform superbly and which are created by experts whose concern is
continuous innovation.
From the ambitious hobby electronics enthusiast to the professional user, products from the
Voltcraft® brand family provide the optimum solution even for the most demanding tasks. And the
remarkable feature is: we offer you the mature technology and reliable quality of our Voltcraft®
products at an almost unbeatable price-performance ratio. In this way, we aim to establish a long,
fruitful and successful co-operation with our customers.
We wish you a great deal of enjoyment with your new Voltcraft® product!




 
The sound level measuring device is a digital device for measuring the sound level in Decibel (dB)
and corresponds to the demands of EN 61 672-1. The SL-451 is classied in Class 2 for general
eld tests (e.g. operative measurements). The measuring ranges can be calibrated via the integra-
ted adjustment feature.
The values measured and the current measurement units/functions are displayed digitally on a large
LCD (Liquid Crystal Display).
A bar graph display enables the detection of fast and short sound levels.
Two frequency weighting lters (A/C) and two time weightings (fast/slow) can be preselected and
allow universal application.
Measuring is possible in a frequency range from 31.5 Hz (Hertz) up to 8 KHz (Kilo Hertz) as well as
a sound level from 30 to 130 dB.
The maximum values as well as the display content can be saved.
In order to suppress interfering wind noise, the device features an attachable wind protector, which
does not interfere with the sound level measuring.
The measuring device also features a display illumination. A data logger for internal measuring value
recording is installed. The measuring values can be transferred to a computer and analysed there
via the USB interface. A proportional voltage (10 mV DC/dB and max. 1 Vrms AC/130 dB) is output
at the AC/DC analog output.
A 9-V block battery (type 1604A) or the power adapter are required for operation.
Measurements must not be carried out under unfavourable ambient conditions.
Unfavourable ambient conditions are:
• wetness or high air humidity
• dust and ammable gases, vapours or solvents
• thunderstorms or similar conditions such as strong electrostatic elds etc.
Unauthorised conversion and/or modication of the device are inadmissible because of safety and
approval reasons (CE). Any usage other than described above is not permitted and can damage the
product and lead to associated risks such as short-circuit, re, electric shock, etc. Please read the
operating instructions thoroughly and keep them for further reference.



 
• Sound level measurement device • Power adaptor
• Carrying case • Tripod
• Wind protection • Screw driver which can be calibrated
• USB interface cable • 4 m microphone extension cable
• Software CD • Operating instructions
• 9 V block battery
 
An exclamation mark in a triangle indicates important instructions in this operating
manual which absolutely have to be observed.
The symbol can be found when you are to be given tips and information on operation.
 






Dear Customer, the following safety instructions are intended not only for the protection of your
health but also for the protection of the device. Please read carefully through the following points:



• The product is not a toy and should be kept out of reach of children and pets!
• On commercial premises, the accident prevention regulations of the Association of Industrial Profes-
sional Associations with respect to electrical systems and operating equipment must be observed.
• In schools, training centres, Hobby and DIY workshops, the handling of measuring appliances must
be responsibly supervised by trained personnel.
• Wear suitable hearing protection in loud environments. Excess sound levels may cause hearing
damage.
• When used in conjunction with other devices, observe the operating instructions and safety notices
of connected devices.
• The product must not be subjected to heavy mechanical stress or intense vibration.
• The product must not be exposed to electromagnetic elds, extreme temperatures, direct sunlight or
dampness.
• The device must not be exposed to humidity or liquids.
• The product should not be used immediately after it has been brought from an area of cold tempe-
rature to an area of warm temperature. Condensed water might destroy the product. Wait until the
product adapts to the new ambient temperature before use.
• If there is reason to believe that safe operation is no longer possible, put the device out of operation
and secure it against unintended operation. Safe operation is no longer possible if:
- the product shows visible damages,
- the product no longer works and
- the product was stored under unfavourable conditions for a long period of time,
- the product was subject to considerable transport stress.
• The manufacturer or supplier accepts no responsibility whatsoever for incorrect displays or the
consequences which can arise from such incorrect displays.



• Correct polarity must be observed while inserting the (rechargeable) battery.
• The (rechargeable) battery should be removed from the device if it is not used for a long period of
time to avoid damage through leaking. Leaking or damaged (rechargeable) batteries might cause
acid burns when in contact with skin, therefore use suitable protective gloves to handle corrupted
(rechargeable) batteries.
• (Rechargeable) batteries must be kept out of reach of children. Do not leave (rechargeable) batteries
lying around, as there is risk, that children or pets swallow them.
• (Rechargeable) batteries must not be dismantled, short-circuited or thrown into re. Never recharge
non-rechargeable batteries. There is a risk of explosion!

• The product must not be used for medical or public purposes.
• Repair works must only be carried out by a specialist/ specialist workshop.
• If you have queries about handling the device, that are not answered in this operating instruction, our
technical support is available under the following address and telephone number:

International: www.conrad.com/contact
United Kingdom: www.conrad-electronic.co.uk/contact


 
1. Measuring microphone with wind protection
2. LC display
3. Button “REC” to record measuring values
4. Button “SETUP” for basic settings
5. Button “FAST/SLOW” for measuring time switching
6. Button “MAX/MIN” for display of the maximum/minimum values
7. Button “LEVEL” for switching the measuring range
8. Button “Light” for display illumination
9. Button “A/C” for rating curve
10. “Hold” button to freeze a measuring value
11. ON/OFF button
12. Treaded socket for tripod
13. Battery compartment on the back side
14. Socket for power adaptor connection
15. Mini-USB port for interface cable
16. Analogue output
17. CAL calibration potentiometer



A. MAX/MIN Recording of the maximum/minimum values
B. Bar graph Analog display with range indication
C. TIME/DATE Date/time display
D. Measuring value
E. Clock symbol Active auto power OFF function
F. BAT Battery replacement display
G. REC Active data recording
FULL Internal data memory full
H. dBA Weighting lter for A line (=hearing)
dBC Weighting lter for C line (=linear)
I. HOLD The current reading is held
J. AUTO Automatic measuring range setting is active
K. FAST Fast time benchmarking (125 ms/measuring operation)
SLOW Slow time benchmarking (1s/measuring)
L. OVER Measuring range is exceeded
UNDER Measuring range is undercut


 
• Insert the CD into the CD-ROM of your computer.
• The installation will start automatically. If not, please go to your CD-ROM directory, and open the
installation le “autorun.exe”.
• Select your desired language from German, English and French.
• Follow the instructions on the dialog box, select the destination for the installation and complete the
installation.
• For further information, please refer to the operating instructions on the CD provided.
• The enclosed software is the Voltsoft standard edition. The professional version (Voltsoft Data
Logger, No. 10 13 33) is an optional item which you can purchase separately. If you purchase the
professional version, you will get the license key. Follow the steps in the Voltsoft user manual, to
register and upgrade your software to the professional version.
• Voltsoft software updates to the latest version of the Voltsoft program are available when the pro-
gram is running and the Internet is connected; or check for the latest Voltsoft update via
“http://www.conrad.com”
 

Before the initial operation of this meter, you must rst install a new 9 V block battery. Battery
installation is described in the “Maintenance and cleaning” section.

For long-term measuring operations, you have to use the enclosed power adaptor. Plug the power
adaptor into the DC socket on the side and connect it with a suitable mains outlet.


 
The sound level measuring device SL-451 has an integrated data logger. The data logger can record
measuring values with time stamp. Upon commissioning, you have to set the time and date.

Turn the measuring device off.
Keep the button “SETUP” depressed and turn the device on. Keep both
buttons depressed until “TIME” appears on the display.
After letting go of both buttons, the setup menu with the default date display
appears.
To access the individual setting points, press “SETUP” until the desired
parameter appears.
You have to conrm and complete your settings by pressing “HOLD” for
saving the data. Then the setup menu is terminated and the measuring
display appears.

In the SETUP menu, press the button “SETUP” 1x.
The display for setting the minutes “m” appears.
Press the “LEVEL” button to set the current minute time. Keep the button
depressed to set the value faster. The values ascend and start again at the
beginning.
Switch to the next setting with the button “SETUP”, or complete your setting
with the button “HOLD”.



In the SETUP menu, press the button “SETUP” 2x.
The display for setting the hours appears. The time format corresponds to
12h (P = afternoon / A = morning).
Press the “LEVEL” button to set the current time in hours. Keep the button
depressed to set the value faster. the values ascend and start again at the
beginning.
Switch to the next setting with the button “SETUP”, or complete your setting
with the button “HOLD”.

In the SETUP menu, press the button “SETUP” 3x.
The display for setting the day appears.
Press the “LEVEL” button to set the current day. Keep the button
depressed to set the value faster. The values ascend and start again at the
beginning.
Switch to the next setting with the button “SETUP”, or complete your setting
with the button “HOLD”.

In the SETUP menu, press the button “SETUP” 4x.
The display for setting the month appears.
Press the “LEVEL” button to set the current month. Keep the button
depressed to set the value faster. The values ascend and start again at the
beginning.
Switch to the next setting with the button “SETUP”, or complete your setting
with the button “HOLD”.



In the SETUP menu, press the button “SETUP” 5x.
The display for setting the year appears.
Press the “LEVEL” button to set the current year. Keep the button
depressed to set the value faster. The values ascend and start again at the
beginning.
Switch to the next setting with the button “SETUP”, or complete your setting
with the button “HOLD”.

The last menu point serves to delete all preset parameters. This is required
when you need to change the batteries. Always delete the SETUPfunctions
rst prior to making the new settings.
In the SETUP menu, press the button “SETUP” 6x.
The display for deleting the settings appears. Press the button “SETUP” to
access the rst setting point or the button “HOLD” to delete the settings.
After deletion, the device automatically switches to measuring mode.
 
The sound level meter has various extra functions that make it easier to carry out measurements
using the device and also extend its range of application. These extra functions are:

In order to avoid that the operating life of the battery is shortened unnecessarily, an automatic
switch-off function has been implemented. The device is automatically switched off if no button
has been pressed over a period of about 15 minutes. You can switch the device back on with the
“Power” button.
This function can be turned on and off in measuring operation by pressing the “SETUP” button.



The measured value currently being displayed is held in the display. The active function is shown in
the display by “HOLD”.
• Press the “HOLD” button to activate this function.
• Press again to switch back to the continuous measuring mode

With continuous measuring, the display only shows the maximum or minimum value. This measu-
rement function makes it easier for you to determine the peak level. The active function is shown in
the display by “MAX” or “MIN”.
Press the button “MAX/MIN” to activate this function. Each additional press of the button switches to
the next display mode. MAX, MIN, normal measuring mode, MAX, MIN...

The frequency of the measuring signal is weighted with the help of two benchmark curves.
Line A represents the characteristic hearing line of the human ear. Humans perceive deep sounds
as quieter than mid or treble sounds. Line C weighs the frequency spectrum linear and without lter
(actual sound level).
Press the button “A/C” to switch this lter. The active lter is shown as “dBA” or dBC” on the display.

The sound level meter has four measuring ranges. The bottom range is from 30 to 80 dB, the
medium range from 50 to 100 dB, and the top range from 80 to 130 dB. The automatic range is from
30 to 130 dB.If one of these ranges is exceeded or undercut, “UNDER” or “OVER” appears on the
display.
Switch to the next higher/lower measuring range. To switch, press the button “LEVEL”.



The signal can be measured with two different measuring intervals. For rapidly changing sound
levels (horn, shot, etc.), you have to set the time rating to “FAST”. The measuring duration is
125 ms/measuring operation. For slow and persistent sound levels (noise, humming, etc.), the time
rating must be set to “SLOW”. The measuring duration is 1 s/measuring operation.
To switch, press the button “FAST/SLOW”.
 





The sound level meter corresponds to the European standard EN 61 672-1 for sound level meters.
To apply the device in line with the standard, it must be calibrated with the benchmark curve A (dBA)
prior to each measuring operation, meaning tested and if necessary matched with a sound calibrator
Class 2 acc. to IEC 60942. The accuracy must be checked again after each measuring operation.

Switch the sound level meter on.
Select the corresponding settings (dBA, measuring range up to 100 dB or higher and FAST time
rating).
If necessary, deactivate the the functions “MAX” and “HOLD”.
Plug the microphone of the sound level meter into the opening of the sound calibrator. Ensure a tight
t so that the calibration chamber in the sound calibrator is sealed.
Set the following parameters on the sound calibrator: 94 dB at 1 kHz
The measuring device should now show a sound level of 94 dBA. If this is not the case, the measu-
ring device must be calibrated.
With the enclosed screwdriver, carefully turn the calibration point on the side (CAL calibration
potentiometer 17) until the value on the display is exactly 94.0 dBA.
The measuring device is ready for use.



 


• Point the sound level meter with the microphone directly on the sound source.
• In order to not inuence the soundwaves, keep the measuring as far away from your body as
possible at your outstretched arm or attach it to the enclosed tripod.
• If possible, move approx. 2 m away from the measuring spot.
• If necessary use the microphone extension cable supplied. Connect (screw) the extension cable
between the microphone and the measuring device
• There is a tripod thread on the back of the casing.
• Avoid vibrations or movements.



• For easier legibility at dusk or dark, you can illuminate the display. Press the button with the lamp
symbol for this purpose. To turn off press this button again.
• Turn the display illumination and/or the measuring device off when not in use.


 

You can preset the interval time of the integrated data logger from 1 to 59 seconds. In REC mode,
the data logger only records a measuring value in the prescribed interval.

Turn the measuring device off.
Keep the button “LIGHT” depressed and turn the device on.
Keep both buttons depressed until “INT” appears on the display.
Press the “LEVEL” button to set the interval time in seconds. Keep the button
depressed to set the value faster. The values ascend and start again at the
beginning.
You must terminate the setting with the button “HOLD”, otherwise the value
is not saved.

Once the setup settings and the interval times are set, you can start the measuring value recording.
Turn the measuring device on, and select the desired measuring parameters (measuring range,
lter, etc.).
Press “REC”. The recording starts. The display indicates the symbol “REC”.
You stop the recording by pressing the button “REC” again.


• The recorded data can only be read out via the interface.
• If all memory slots are full, the display shows “FULL”. Delete the memory after each data transfer.



A full memory can be deleted with a key combination.
Turn the measuring device off
Keep the button “REC” depressed and turn the device on. Keep both buttons
depressed until “CLR” appears on the display.
The memory is deleted. The measuring device automatically switches back
to measuring operation.
 
Via the integrated USB interface, you can transfer the saved measuring values to a software for
saving and evaluating. Proceed as follows to connect the sound level meter to your computer:
Turn on the computer and the Voltsoft software.
Turn on the device and turn off the auto power off function (see chapter 10)
Connect the device to a vacant USB port on a personal computer.
The device is detected by the computer, follow the operating instructions of the Voltcraft software.
 
The sound level meter SL-451 has an analog signal output at which a voltage
proportional to the measuring signal can be picked up. This output can be used for
additional measuring functions like e.g. an X-Y scriber, etc. You can select between
direct and alternate voltage.
The connection is established via an optional 3.5 mm stereo jack plug. Depending
on the purpose, connect the output to contact 1 and 3 (for AC) or contact 2 and 3
(for DC).
• 1 = AC output (max. 1 Vrms/130 dB, impedance 100 Ohm)
• 2 = DC output (10 mV/dB, impedance 1 kOhm)
• 3 = GND ground potential
Never short-circuit the output, otherwise it may be damaged.


 
The device is maintenance-free apart from the need to replace the batteries and cleaning it once in
a while. Use a clean, lint-free, antistatic and slightly damp cloth to clean the device. Do not use any
abrasive or chemical agents or detergents containing solvents.

If the battery symbol appears on the display, the batteries have to be replaced as soon as possible
to prevent inaccurate measurements. Proceed as follows to replace the batteries:
• Switch off the measuring instrument.
• Slide the battery compartment cover on the rear off the casing in the direction of the arrow.
• Replace the at 9 V battery with a new one of the same type (e.g. 1604 or 6F22).
• Close the measuring instrument again carefully by proceeding in the reverse order.



You can order a matching replacement battery stating the order number 652509.
 
In purchasing this device, you have acquired a product which has been designed with state-of-the-
art technology and is operationally reliable. Nevertheless, problems or faults may occur. For this
reason, the following is a description of how you can eliminate possible malfunctions yourself.
 
The device does not work. Is the battery dead? Check the battery status.
No measuring value change. Is the HOLD function activated?


 

In order to preserve, protect and improve the quality of environment, protect human
health and utilise natural resources prudently and rationally, the user should return unser-
viceable product to relevant facilities in accordance with statutory regulations.
The crossed-out wheeled bin indicates the product needs to be disposed separately and
not as municipal waste.

The user is legally obliged  to return used batteries and recharge-
able batteries. 
Batteries/ rechargeable batteries containing hazardous substances are marked with
the crossed-out wheeled bin. The symbol indicates that the product is forbidden to be
disposed via the domestic refuse. The chemical symbols for the respective hazardous
substances are  = Cadmium,  = Mercury,  = Lead.
You can return used batteries/ rechargeable batteries free of charge to any collecting
point of your local authority, our stores or where batteries/ rechargeable batteries are
sold.
Consequently you comply with your legal obligations and contribute to environmental protection!
 

CPU:
RAM:
Harddisk:
OS:
Software support:
Pentium 600 MHz or above
128 MB or above
500 MB free space
Microsoft Windows® XP, 7, 8.1 or Vista™
.NET framework 2.0
Observed standards: IEC 61672-1 Class 2
Operating voltage: 9 V block battery / power adaptor 9 V
Current consumption: max. 16 mA
Battery lifetime: aprrox. 50 h (alkaline battery)
Auto power off: After approx. 15 minutes if no button is pressed
Display: LCD, 2000 counts
Resolution: 0.1 dB (refresh 2/s)
Data memory: 32600 memory slots