Delta OHM HD2010UC/A User manual

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Operating manual
Integrating Sound Level Meter
Spectrum Analyzer
HD2010UC/A
www.deltaohm.com
English
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1. Microphone.
2. Preamplifier.
3. Preamplifier or extension cable connector.
4. Symbol showing measurement status: RUN, STOP, PAUSE, RECORDING or HOLD.
5. Keypad LEFT key: in graphic mode, it moves the selected cursor towards lower values.
6. Keypad CURSOR key: in graphic mode, it allows to select one or both of the two cursors.
7. HOLD key: it temporarily stops display updating.
8. MENU key: it activates the different configuration menus of the instrument.
9. REC key (recording): combined with START/STOP/RESET, it activates data recording on
memory. When pressed for at least 2 seconds, the displayed data can be stored in memory as a
single record; alternatively, the Auto-Store mode can be activated.
10. PAUSE/CONTINUE key: pauses integrated measurements. From PAUSE mode, integrated
measurements can be resumed by pressing the same key. In PAUSE mode, press
START/STOP/RESET to reset measurements.
11. SELECT key: enables modification mode of displayed parameters by selecting them in se-
quence.
12. ENTER key. It confirms entered data or edited parameters.
13. LEFT key: in the menu, it is used when editing parameters with attribute. In graphic mode, it
reduces the vertical scale.
14. M12 connector for RS232C multi-standard serial port and USB.
15. Auxiliary power supply connector.
16. DC output connector (∅2.5mm jack).
17. DOWN key: in the menu, it selects the next line or decreases the selected parameter. In graphic
mode, it increases the vertical scale levels; the graph is shifted downwards.
18. RIGHT key: in the menu, it is used when editing parameters with attribute. In graphic mode it
extends the vertical scale.
19. MODE key: selects in circular order the instrument’s different view modes, from the display of
5 channels in numeric format, to the profile, to the octave and third octave spectrum (“Third Oc-
tave” option) and to the statistics analysis screens.
20. UP key: in the menu, it selects the previous line or increases the selected parameter. In graphic
mode, it decreases the vertical scale levels; the graph is shifted upwards.
21. START/STOP/RESET key: when pressed in STOP mode, it starts the measurements (RUN
mode). In RUN mode, it stops the measurements. When pressed in PAUSE mode, it resets the
integrated measurements, such as Leq, SEL, MAX/MIN levels, etc.
22. PROG key: activates the program selection mode.
23. PRINT key: transfers the displayed data to the serial port. When pressed for more than 3 sec-
onds, it enables the continuous printing (Monitor). Monitoring will be stopped by pressing the
key once more.
24. ON/OFF key: turns the instrument on and off.
25. Keypad RIGHT key: in graphic mode, it moves the selected cursor towards higher values.
26. Battery symbol: indicates the battery level. The more the symbol is empty, the more the battery
has run down.
27. LINE: un-weighted output connector (∅3.5mm jack).

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CONNECTOR FUNCTION
The instrument is equipped with five connectors: one in front, one to the side and three at the bot-
tom. The figure on page.2 shows:
n. 3 - 8-pole DIN connector for preamplifier or extension cable. The connector, located on the
instrument front face, has a positioning notch and a screw ring nut to ensure proper lock-
ing.
n.14 - M12 connector for RS232C multi-standard serial port and USB. For the connection to a
COM port (RS232), you have to use the dedicated serial null-modem cable (code
HD2110RS), fitted with a 9-pole female connector conforms to class 1 specifications ac-
cording. As alternative the sound level meter can be connected to a PC USB port by using
the dedicated cable (HD2110USB), fitted with type A USB connector.
n.15 - Male connector for external power supply (∅5.5mm-2.1mm socket). It requires a
9…12Vdc/300mA power supply. The positive (pole) power supply must be connected to
the central pin.
n.16 - Jack (∅2.5mm) or the analogue (DC) A weighted output with FAST constant time up-
dated 8 times/s.
n.27 - Jack (∅3.5 mm) for the analogue (LINE) un-weighted output placed on the right side of
the conical part/detail.

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INTRODUCTION
HD2010UC/A is an integrating portable sound level meter performing either spectral or statis-
tical analysis. The instrument has been designed combining maximum usage flexibility, cheapness,
and simplicity of use. Attention has been paid to the possibility of adjusting the instrument to regu-
latory modifications, and to the necessity of meeting its users’ needs of today and tomorrow. The
HD2010UC/A can be integrated with other options to extend its application scope at any time; the
firmware can be updated directly by the user by means of the supplied Noise Studio program.
The HD2010UC/A conforms to IEC 61672-1 of 2002, IEC 60651 and IEC 60804 specifications
with class 2 or class 1 tolerances. The constant percentage bandwidth (CPB) filters meet IEC 61620
class 1 specifications.
The HD2010UC/A is an integrating sound level meter and analyzer suitable for the following appli-
cations:
•Assessment and monitoring of the environmental noise level,
•Spectral analysis by octave bands from 31.5Hz to 8kHz,
•Optional (HD2010.O1) spectral analysis by third octave bands from 25Hz to 12.5kHz,
•Statistical analysis with percentile levels calculation from L1to L99
•Capture and analysis of sound events,
•Measurement at the workplace,
•Selection of personal protective equipment (SNR, HML and OBM methods),
•Soundproofing and acoustic treatment,
•Production quality control,
•Measurement of machine noise,
•Optional architectural and building acoustics measurements.
Using the HD2010UC/A sound level meter it’s possible to log the noise time profile with par-
allel frequency weightings and time constants acquisition. The sound level meter , automatically
stores noise analysis of multiple acoustic descriptors as a data recorder, with a storing capacity of
more than 23 hours at the maximum temporal resolution. For long term noise monitoring, it’s pos-
sible to record together, with a time period from 1 s to 1h, 5 programmable parameters, the average
spectrum and complete statistical analysis: with the “Memory module” option HD2010.O0 (it dou-
bles the standard memory capacity), the HD2020UC/A can store, with a time interval of 1min, the
noise multi-parameter and statistical analysis for more than 10 days. For particular needs it’s possi-
ble to increase even further the memory capacity using the HD2010MC module. This device is sup-
plied with a 2GB SD memory card.
The HD2010UC/A has a versatile trigger function for the noise event capture, with the addi-
tional possibility to filter false events; this is made verifying that the noise event level variation has
a certain duration. For each identified event, it’s possible to record 5 integrated parameters (user de-
fined), average spectra in octave and third octave bands and the noise levels probability distribution
sampled during the specific event. The event parameters recording doesn’t exclude the normal and
interval standard storing. The event trigger function can be started also manually pressing a key on
the keyboard.
The advanced functions of HD2010UC/A analyser, allow multi-parameters profile acquisi-
tion in parallel with reports sequences with dedicated parameters, average spectra and complete sta-
tistical analysis. Moreover, during recording, trigger function allows to identify noise events and to
record 5 user defined parameters, average spectrum and statistical analysis, all integrated during the
event duration.
During data-logging are available up to 9 different markers to highlight the occurrence of spe-
cific situations to be considered in the time history post processing phase.
A timer allows to schedule a delayed acquisition start.

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Different recordings can be later recalled from internal memory and displayed on the graphi-
cal screen using the “Replay” function that shows the time history of recorded noise levels. The
USB interface high transfer speed, combined with RS232 flexibility, allow fast data transfer from
sound level meter internal memory to PC memory but also to control a modem or a printer. For ex-
ample, in case the internal memory is not sufficient, that’s the case of long term monitoring, it’s
possible to activate the “Monitor” function. Such function allows to transmit displayed data
through the serial interface, recording them directly on PC memory.
The HD2010UC/A can be fully controlled via a PC using the multi-standard serial interface
(RS232 and USB), using a dedicated communication protocol. Through RS232 serial interface it’s
possible to connect the HD2010UC/A to a PC also by means of a modem.
Together with the logging of the overall noise level profiles, the spectral analysis is carried out
in real time for octave bands and for third octave bands, as an option. The sound level meter calcu-
lates the spectrum of the sound signal twice a second and integrates it linearly for up to 99 hours.
The average spectrum or the multi-spectrum profile starting from 1s, are displayed together with an
A, C or Z wideband overall level; this allows a fast comparison between spectrum and overall level.
Moreover the spectrum can be shown both as linear and as A or C frequency weighted, for a fast
evaluation of the different spectral components audibility.
As a statistical analyser, the HD2010UC/A samples the sound signal 8 times per second with
A-frequency weighting and FAST time constant, and analyses it statistically according to 0.5 dB
classes. Statistical analysis is shown in a graphic form as probability distribution and cumulative
distribution with percentile levels from L1to L99.
For further analysis, the LINE un-weighted output allows to record the noise either on tape
or directly on a PC equipped with a data acquisition card.
The calibration can be made either using an acoustic calibrator (type 1 or 2 according to IEC
60942) or the built-in reference generator. The electric calibration employs a special preamplifier
and checks the sensitivity of the measuring channel, microphone included. A protected area in the
non-volatile memory, reserved to factory calibration, is used as a reference in the user’s calibra-
tions, allowing to keep instrument drifts under control and preventing the instrument from wrong
calibrations.
The user can check on site the complete sound level meter’s functionality thanks to a diagnostic
program.
The HD2010UC/A sound level meter can perform the measurements required to evaluate
workers’ noise exposure (D.L. N.81/2008, UNI 9432/2011 and ISO 9612/ 2011 standards). Accord-
ing to UNI EN 458, the personal protective equipment can be selected through octave band spec-
trum analysis (OBM method) and a comparison of the A and C-weighted equivalent levels that can
be measured simultaneously (SNR method). If an undesired sound event produces an over-load in-
dication, or simply alters the result of an integration, its contribution can be excluded using the ver-
satile Back-Erase function. The impulsivity of a noise source is easily evaluated (according to crite-
ria defined in UNI 9432 standard) measuring the A weighted equivalent sound pressure level with
Impulse time constant (LAeqI).
The cyclic, fluctuating and impulsive noise sources identification is simple thanks to the
powerful recording functions of HD2010UC/A analyser which allows, using a single measurement
setup, to solve the most of situations encountered in working environments. The combination of
powerful measurement and recording functions of HD2010UC/A with the analysis functions of the
post processing Noise Studio (supplied with all sound level meters) software module “Worker’s
protection”, allows a fast and efficient management of noise measurements for health and safety
evaluations in workplaces.

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The HD2010UC/A sound level meter is suitable for sound level monitoring, acoustic mapping, and
the assessment of the acoustic climate with capture and analysis of sound events. When measuring
traffic noise near airports, railways and roads, the sound level meter can be used as a multi-
parameter sound recorder, combining spectrum (option “Third octave” from 25Hz to 12.5KHz) and
statistical analyser features. Remote electrical calibrations and diagnostic tests can be executed us-
ing its remote control functions.
The HD2010UC/A, sound level meter, with the “Third Octave” and “Reverberation Time” options,
can perform all measurements prescribed by the regulations on building acoustics evaluation (ISO
140). The sound level meter powerful DSP calculates 32 spectra/second, and it can measure rever-
beration times both using the sound source interruption and the impulsive source integration tech-
nique according to UNI EN ISO 3382. The HD2010UC/A sound level meter analyses the noise
level decays with the Ordinary Least Squares method, simultaneously both by octave from 125Hz
to 4KHz and, if option HD2010.O1 is installed, by third octave bands from 100Hz to 12.5KHz ac-
cording to survey, engineering and precision methods defined in UNI EN ISO 3382-1/2009 and
3382/2008.
The HD2010UC/A can be configured in accordance with different customers’ needs: the available
options can be activated on the new instrument, as well as, later on, when requested by the user. The
provided options are:
“Third Octave” option
It adds a parallel bank of third octave filters from 25Hz to 12.5 kHz in class 1, according to IEC
61260. The filter bank works in parallel to all other measurements. The audibility of the different
spectrum components can be evaluated applying A or C frequency weightings or thanks to the iso-
phone (equal loudness level) curve calculation function of Noise Studio, a program supplied with
the instrument.
“Reverberation Time” option
Through this option the HD2010UC/A can carry out reverberation time measurements accord-
ing to the techniques of the interruption of the sound source and of the impulsive source according
to EN ISO 3382-2/2008 requirements. This measurement is made simultaneously for octave band
from 125 Hz to 8 kHz and optionally for third octave band from 100 Hz to 10 kHz. The sampling
interval equals 1/32s and the calculation of EDT, T10, T20 and T30 reverberation times is made
automatically for all bands.

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HD2010UC/A BLOCK DIAGRAM
The block diagram shows the main elements of the HD2010UC/A sound level meter.

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THE MICROPHONE
The UC52 condenser microphone is pre-polarized (electret) and has a ½” standard diameter.
The frequency response in free field is flat from 20Hz to 16kHz in type 1 HD2010UC/A version
(UC52/1). Microphones used for type 2 precision sound level meter versions have a flat frequency
response from 25Hz to 10KHz.
THE OUTDOOR MICROPHONE UNIT HD WME
The microphone unit HD WME is suitable for long term outdoor noise measurements, in-
cluding from fixed unattended station. The unit is adequately protected from rain and wind; the
heated preamplifier allows performing measurements within a wide weather condition range.
The special preamplifier is fitted with a calibration circuit that uses a charge partition technique in
order to calibrate the unit, inclusive of the microphone capsule. The output driver allows guiding
cables up to 10m in length, without important losses.
HD WME unit must be positioned in vertical position to fulfil correctly its function as weather
protection. Used in this way it can measure both community and aircraft noise (90° and 0°). Delta
Ohm sound level meters apply spectral corrections to measurements in order to comply with
IEC61672 type 1 and type 2 tolerances.
Installation and uninstallation procedure is very easy;
in this way periodical acoustic verification (using a
standard ½ calibrator) of the microphone is as simple
as for a standard measurement microphone.

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The unit is composed of a central body plus the following components:
•HD SAV3: wind-screen (3)
•HD WME1: ant-bird spike (4)
•HD WME2: rain shield (2)
•HD WME3: stainless steel support (1)
•Microphonic capsule with optimized free field correction
•Microphone preamplifier: HD2010PNE2W: heated preamplifier for UC52 microphone in-
cluding CTC calibrator and driver for up to 10m extension cable.
•Extension cable standard 5m length (10m on request).
For detailed information on the use of HD WME unit, please refer to the specific part of this
manual on page 49; for information on assembling and disassembling the unit please refer to ap-
pendix on page 144.
THE PREAMPLIFIER
The preamplifier amplifies the weak signal provided by the microphone. It has a gain select-
able between 0 and 20 dB and is supplied with a charge partition calibration device which allows to
measure the frequency response of the whole amplification chain, microphone included as de-
scribed on page 49).
The output driver allows transmitting the microphone signal via a cable to a distance up to 10m.
The preamplifier of HD2010UC/A together with UC52 microphone can measure signals up to 140
dB with a frequency response (excluding microphone) up to 40kHz
The following models are available:
•HD2010PNE2:connector for ½” UC52 microphone and driver for up to 10m extension cables.
This preamplifier, supplied with CTC electric calibration device, can be directly plugged into the
HD2010UC/A sound level meter or connected via extension cable (up to 10mt).
•HD2010PNE2W: heated preamplifier with connector for ½” UC52 microphone and driver for

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extension cables. This preamplifier, supplied with CTC calibration device, can be connected to
sound level meters using the 5mt supplied extension cable (10m as option).
•HD2010PNE4: preamplifier for MC24E ¼” microphone. Equipped with CTC calibration device
for electric calibration and driver for cable up to 100m. Requires the HDP079A02 microphone
adapter.
•HD2010PNE4H: preamplifier for MC24EH ¼” microphone. Equipped with CTC calibration
device for electric calibration and driver for cable up to 100m. Requires the HDP079A02 micro-
phone adapter.
THE INSTRUMENT
The preamplifier signal comes to the instrument receiver and its output is sent to the LINE
connector and to the A/D converter input.
The A/D converts the analogue signal into the numeric format at 20 bits. The measurement dynam-
ics, exceeding 140 dB, is divided into 5 ranges using a variable gain amplifier with steps of 10 dB,
between 0 dB and 20 dB, positioned at the input.
Then the digitalized signal reaches the DSP for processing.
The levels either wideband (A, C and Z) or with constant percentage bandwidth (both octave and
third octave) are calculated in parallel in the DSP. Peak (C and Z) levels are also calculated. The
levels calculated by the DSP are transmitted to the microprocessor for further processing, ready to
be displayed, stored and printed.
The microprocessor controls all the instrument processes: management of the electrical cali-
brator, Flash memory, display, keyboard and multi-standard serial interface (RS232 and USB).
The microprocessor also supplies the electrical signal corresponding to the A weighted instant level
with FAST time constant, sent to DC output.

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DESCRIPTION OF DISPLAY MODES
The HD2010UC/A measures simultaneously 3 selectable parameters (statistic ones too) and
displays them at a fixed frequency corresponding to 2 measurements/s; simultaneously measures the
A weighted sound pressure level with FAST time constant and displays it at 8 samples/s. It calcu-
lates also the spectra by octave bands and by third octave bands (when the “Third Octave” option is
active), with a maximum frequency of 2 spectra/s. As a statistical analyser, it calculates the prob-
ability and the cumulative distribution. To be able to display all these data, the HD2010UC/A, pro-
vides 6 different display modes as shown in the figures below.
56.9
60.8
79.3
30 110
01:08:25
Tint= s 10
LFp
Leq
Lpk
dBA
dBC
dBC
Fig. 1 - SLM Fig. 2 - Time Profile
Fig. 3 - Octave Fig. 4 - Third Octave
Fig. 5 – Probability distribution Fig. 6 – Percentiles levels
Press MODE at any time to jump from a screen page to the next one. The display will show: first
the SLM screen with 3 measuring parameters in numeric format, the Profile screen of the A
weighted sound pressure level with FAST time constant (LAFp), then the Octave screen with the oc-
tave spectra from 31.5 Hz to 8 kHz and, (if the “Third Octave” option is active) the third octave
spectra from 25Hz to 12.5 kHz, the probability distribution and the percentile levels screens. .
Upon power on, the sound level meter displays the SLM screen.
Display of Octave and Third Octave display can be disabled using the specific parameters in
the menu (Menu >> Statistic Analyser >> Display…). Also the Probability and Percentiles screens
can be disabled, using parameter Menu >> Statistic Analyser >> Statistics Display (please see para-
graph “DESCRIPTION OF MENU FUNCTIONS” on page 39)

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Some display indications are common to all display modes; they are (see picture):
•Measurement status indicator
•Overload/Under-range indicator
•Battery level indicator
The first symbol in the left corner at the top shows
the measurement status of the sound level meter.
•RUN: the instrument is measuring.
•PAUSE: the calculation of integrated measure-
ments and the recording of measurement have
been suspended. Instantaneous parameters are
still being measured and displayed.
•REC: the instrument is measuring and re-
cording.
•STOP: the instrument is not making any meas-
urement.
•HOLD: the calculation of integrated measurements has come to the end of the set integration
interval, or HOLD was pressed.
•P(Print): indicates that printing is in progress.
•M (Monitor): indicates (flashing) that continuous data printing has been started.
•R (Replay): appears (flashing) when the “Memory Navigator” program is in use, to view a file
saved in the instrument memory (see page 46).
Just on the right of the symbol indicating the logging mode, there is the symbol showing a
possible overload or under-range. An arrow directed upwards indicates that the input level has ex-
ceeded the maximum measurable level, while an arrow directed downwards indicates that the input
level is lower than the minimum measurable level.
The maximum measurable level corresponding to the selected measurement range is given in
the technical specifications (see page.94). The minimum measurable level is 80 dB lower than the
maximum one. The noise levels for each frequency weighting are listed in the technical specifica-
tions. Using an appropriate parameter (MENU >> Instrument >> Measurement >> Overload Level)
you can program the maximum measurable limit at lower levels (see page 94).
An empty arrow indicates that the limit has been exceeded, while a full arrow indicates that
the overload is in progress.
The integration time Tint, programmable between 1s and 99h, is displayed to the right of the
overload indicator. When the integration mode is set on MULT, the “Tint” symbol on the SLM will
flash (see the “DESCRIPTION OF THE DIFFERENT INTEGRATION MODES” on page 29).
In the right corner at the top, there is the battery symbol. The more the symbol is empty, the
more the battery has run down. When the instrument autonomy reaches 10%, corresponding to
about 30 minutes, the battery symbol will start flashing. A protection device prevents the instrument
from making measurements with insufficient battery levels and automatically switches off the in-
strument when the battery level is at the minimum.
The battery level, expressed in percentage, is visible in the menu main screen page and in the
program page; press MENU and PROG to access them. To jump back to the measurement screen,
press MENU and PROG again.
Pressing SELECT, you will select in sequence the parameters relevant to the displayed page.
While the selected parameter flashes, use UP and DOWN to change it. Press ENTER to quit the se-
lection mode (automatic exit after 10s).
In graphic display mode, use the UP, DOWN, LEFT and RIGHT keys to change the vertical
scale parameters. The LEFT and RIGHT keys reduce and expand the vertical scale, while the UP

HD2010UC/A - 14 - V4.1
and DOWN keys decrease and increase the levels of the vertical scale; the graph is so shifted up-
wards or downwards, respectively.

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SLM (SOUND LEVEL METER MODE)
This is the display mode upon power on.
Three parameters (selectable among the following ones) can be displayed simultaneously:
•Instantaneous acoustic descriptors such as Lp, Leq(Short) and Lpk. The instantaneous pres-
sure level is displayed as the maximum level reached every 0.5s.
•Integrated acoustic parameters with wideband frequency weightings, such as Lpmax, Leq,
LIeq and Lpkmax, updated every 0.5s.
•Percentile levels selectable between L1ad L99.
•Sound exposure level.
•Daily personal exposure level.
•Dose and daily Dose with programmable Exchange Rate, Criterion and Threshold Levels.
•Overload Time (in %).
The display is updated every 0.5 seconds.
The data recording depends on the integration mode selected (single or multi) and on the activation
or not of the Auto-Store function change the recording functioning as described in the table below
(see the chapter “DESCRIPTION OF THE DIFFERENT INTEGRATION MODES” on page 29).
Auto-Store: OFF Auto-Store: ON
Integration
SINGLE
Recording twice a second of the 3 pa-
rameters and 8 times a second of LAF.
Automatic Stop at the end of the set inte-
gration interval.
Automatic recording of SLM page, to-
gether with OCTAVE and (as an option)
THIRD OCTAVE, at the end of the set in-
tegration interval.
MULTIPLE
Recording twice a second of the 3 pa-
rameters and 8 times a second of LAF.
Automatic reset of integrated levels at
every integration interval.
Automatic recording of SLM page, to-
gether with OCTAVE and (as an option)
THIRD OCTAVE, at intervals equal to the
set integration time. At the beginning of
each period, integrated levels and spectra
are set to zero.
DISPLAY DESCRIPTION
Left at the top of the display there are the recording status symbol and the overload or under-
range indicator (described at the beginning of this chapter). In the midst there is the integration in-
terval and on the right the acquisition time (hours:minutes:seconds). When the integration mode is
set on MULT (Menu >> Instrument >> Measurements >> Integr.: MULT), the “Tint” symbol
flashes. The battery symbol is in the right corner, indicating battery level.
56.9
60.8
79.3
30 110
01:08:25
Tint= s 10
LFp
Leq
Lpk
dBA
dBC
dBC
Integration interval
A
cquisition time
Maximum level
Minimum level
Displayed parameters
Bar showing
istantaneous level

HD2010UC/A - 16 - V4.1
The “analogue bar” shows the unweighted sound pressure instantaneous level in an 80 dB in-
terval.
Three measuring parameters are displayed under the analogue bar. All displayed parameters can be
freely selectable among the available ones. There are no restrictions in the selection of frequency
weightings. Measuring parameters are displayed with a shortened label, followed by the numerical
value, by the unit of measurement, and, when necessary, by the frequency weighting. The corre-
spondence between the label and the effective parameter is to be found on page 121.
Integrated parameters like Leq (and Lmax or Lmin), which imply the accumulation of the sampled
sound levels, are displayed with a series of dashes (- - - -) until the level remains lower than the
minimum measurable level.
Before starting a new logging, the sound level meter automatically resets all measurements. If
the multiple integration mode is enabled (MENU >> Instrument >> Measurements >> Integration
Mode: MULT), integrated levels will be automatically set to zero at regular intervals equal to the
set integration time Tint.
With the Continuous Recording function, a series of values is stored every 0.5s together with
the parameter displayed in the PROFILE screen, which corresponds to the A weighted sound pres-
sure level with FAST time constant, computed 8 times a second. Each sample corresponds to the
highest sound level (LAFmx) calculated every 0.125s on the level measured every 7.8ms.
SELECTING PARAMETERS
Some measuring parameters (integration interval, measuring range and the 3 parameters) can
be changed directly via the SLM screen.
Pressing SELECT you choose the different parameters in sequence. While the selected parameter
flashes, you can change it with the UP and DOWN keys.
If a parameter with attribute is selected, like, for example, LFp (FAST weighted pressure
level), the relative frequency weighting will also flash (A in the example in the figure). In this case,
pressing UP and DOWN, you can modify the selected parameter without changing the attribute; for
example, if you press DOWN, you can go from LFp A weighted to LSp A weighted. Pressing
RIGHT you’ll jump to the attribute selection, which will be the only one to flash. Use then the UP
and DOWN keys to change the attribute. For example, if you press UP, you can go from A
weighted LSp to Z weighted LSp.
Pressing SELECT let you choose the next parameter; pressing ENTER, or automatically after
approximately 10s, will let you exit the selection mode.
Also the integration mode (see page 29) can be set using the LEFT and RIGHT keys: press
SELECT to choose the integration interval. When the numeric value of the integration interval
flashes, press RIGHT to set the multiple integration mode or LEFT to set the single integration
mode. When the integration mode is set on MULT, the “Tint” symbol flashes.
Parameters can be modified only when the instrument is in STOP mode: if you try to
make changes to any of the parameters while the instrument is in a status other than STOP, you will
be asked to stop the measurement in progress: pressing YES will stop recording and will allow you
to go on modifying parameters; pressing NO recording will continue without interruption.
The above settings can be made through the instrument configuration menus. See a detailed descrip-
tion on page 36.
BACK-ERASE FUNCTION (DATA EXCLUSION)
To stop a measurement in progress when recording, press the PAUSE/CONTINUE key.
All data logged until the moment key was pressed are used for calculation of integrated parameters.
However, there are some cases when it is useful to clear the measurements recorded just before

HD2010UC/A - 17 - V4.1
pressing PAUSE, for example, because they were caused by unexpected events and not characteriz-
ing the sound being examined.
During measurement, press PAUSE/CONTINUE: integrated measurements update will be in-
terrupted. At this point, press the LEFT arrow to delete the last recorded data.
The integration time value will be temporarily replaced by the word ERASE followed by the
time interval (in seconds) to be deleted. Use the LEFT and RIGHT keys to increase or decrease the
erase interval. Displayed integrated parameters change accordingly, allowing to choose the erase
time depending on the effective need. When pressing PAUSE/CONTINUE again, measurement will
start again and the integrated parameters will have been removed from the selected interval.
The erase maximum time, divided into 5 steps, is set from menu: MENU >> Instrument >>
Measurement >> Max Back-Erase. Settable values are: 5, 10, 30 or 60 seconds, with 1s, 2s, 6s or
12s steps, respectively.

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TIME PROFILE MODE
This display mode presents the time profile of the A weighted sound pressure level with
FAST time constant (LAFp). The integration time is equal to 1/8s and the last 100 measured samples
are displayed.
The HD2010UC/A sound level meter calculates the sound level 128 times per second (with a time
period of 7.8ms) and displays the maximum level at intervals equal to 125ms.
Pressing HOLD, the display update will be stopped; however, the instrument continues meas-
uring and pressing HOLD again will restart display updating.
The HOLD status does not affect either Monitor (continuous printing) or recording opera-
tions. When the continuous recording is activated with the single integration mode, the integration
time acts like a timer for data acquisition, stopping automatically the measurement when the time is
elapsed.
This screen-page is not recorded in the Auto-Store mode.
DISPLAY DESCRIPTION
Fig. 7 - Description of the Profile mode display
The Fig. 7 presents the time profile of the A weighted sound pressure level with FAST time
constant.
The integration interval is shown in the left corner at the bottom of the display. Always at the bot-
tom, in the centre, the display shows the measurement unit and the frequency weighting of the
measuring parameter
The amplitude of the vertical scale of the displayed graph corresponds to 5 divisions. The amplitude
of each division is called “scale factor” of the graph and appears in the middle of the vertical axis.
Using the RIGHT (zoom +) and LEFT (zoom -) keys, this parameter is selectable in real time
among 20dB, 10dB or 5dB by division.
Use the UP and DOWN arrows to set the graph full scale with steps equal to the selected scale
factor, starting from the instrument full scale1. In this way, the graph can be shifted UP or DOWN,
depending on the key you have pressed.
An “analogue” bar indicator on the display right side provides the unweighted instantaneous
level of the input sound pressure level, as for the SLM mode bar.
During Recording mode, 4 values of the LAFp level are stored every 0.5s together with the
SLM screen sound levels. Likewise, when the Monitor function is enabled, 4 values are sent to the
interface every 0.5s.
1The instrument full scale is determined by the selection of the input gain by choosing from the menu: MENU >> In-
strument >> Measurements>> Input gain.

HD2010UC/A - 19 - V4.1
The integration mode do not influence this screen recording functioning.
The sound level displayed on this screen can be used as source for the event trigger (see para-
graph “EVENT TRIGGER FUNCTION” on pag. 27).
USING THE CURSORS
To activate cursors on the graph, press CURSOR on the keypad. If you press CURSOR re-
peatedly, either L1 or L2cursor, or both ΔL cursors in “tracking” will be activated in succession: the
selected cursor will flash. Use the LEFT and RIGHT arrows on the keypad to move the selected
cursor on the graph.
The second line at the top of the display shows the level of the measuring parameter and the
time indicated by the active cursor or the time interval and the L1-L2level difference between the
two cursors when they are both active.
The parameter level being lower than the minimum measurable level is indicated by a series of
dashes (- - - - ).
Cursors will be disabled pressing the CURSOR key again.

HD2010UC/A - 20 - V4.1
SPECTRUM MODE (SPECTRUM BY OCTAVE OR THIRD OCTAVE BANDS)
The spectrum analyser operation mode allows the visualisation of frequency spectrum by
octave bands from 31.5Hz up to 8kHz and, if the “Third Octave” option is active, also by third oc-
tave bands from 25Hz to 12.5kHz. Spectral analysis is carried out and eventually recorded without
any frequency weighting (Z) while the spectrum display can be also A or C weighted, for a fast
evaluation of spectral components audibility.
The spectrum by octave bands or by third octave bands is combined, for possible comparisons, with
a wideband level that might be A, C or Z weighted, as programmed.
The average spectrum (AVR) is linearly integrated band by band throughout the integration
time (from 1s to 99h) shared with the SLM mode.
If integration is performed in single mode (MENU >> Instrument >> Measurement >> Inte-
gration Mode: SINGLE), the instrument will automatically switch into the HOLD mode when
reaching the set integration time, allowing to check the result and eventually print or store it. Press
HOLD to continue with the display update.
If the continuous recording is activated (pressing at the same time REC and START keys), the
integration time will act like a timer, stopping automatically the measurement when Tint is elapsed.
If integration is in multiple mode (MENU >> Instrument >> Measurements >> Integration
Mode: MULT), the instrument will automatically reset the levels at the end of the programmed in-
tegration time, starting a new integration cycle (see the “DESCRIPTION OF THE DIFFERENT
ACQUISITION MODES” on page 29); in this way a multi-spectral analysis is obtained with an ac-
quisition time period from 1s to 1h.
Spectral analysis, normally frequency unweighted (Z), can be carried out applying A or C fre-
quency networks. The A or C frequency weighted analysis is used to evaluate audibility of different
spectral components.