Casella 620 Series User manual

USER MANUAL
www.casellasolutions.com
Casella Holdings Limited
Regent House,
Wolseley Road,
Kempston,
Bedford.
MK42 7JY
T:[phone]
F:[phone]
E: [email protected]
620 Series Enhanced Digital
Sound Level Meter
HB3340-03
March 2023

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Contents
Safety and warnings.............................................................................4
Disposal.......................................................................................................... 5
Disclaimer ............................................................................................6
Introduction.........................................................................................7
Instrument features ....................................................................................... 7
Key features ......................................................................................................................7
New features for 2023 ......................................................................................................7
Frequency analysis ............................................................................................................7
Controls ...............................................................................................8
Microphone and pre-amplifier ....................................................................... 9
Soft keys......................................................................................................... 9
Navigation keys............................................................................................ 10
Run/Stop key................................................................................................ 10
Connectivity ................................................................................................. 10
Operation ..........................................................................................11
Batteries....................................................................................................... 11
Turning the instrument On/Off .................................................................... 12
Measurement screens.................................................................................. 13
Main Menu ........................................................................................15
Settings ........................................................................................................ 15
Set UP..............................................................................................................................16
Set Clock..........................................................................................................................16
Language .........................................................................................................................17
Backlight..........................................................................................................................17
Measurement Control.....................................................................................................18
Run Duration ...................................................................................................................19
Calibration reference level..............................................................................................19
Voice Notes .....................................................................................................................20
Memory ....................................................................................................... 20
View Results ....................................................................................................................21

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Delete..............................................................................................................................22
Record Voice Notes.........................................................................................................22
Event data audio .............................................................................................................22
Status ........................................................................................................... 23
GPS Location......................................................................................23
Connectivity.......................................................................................24
Power socket................................................................................................ 24
USB............................................................................................................... 24
Audio socket................................................................................................. 25
System Tools......................................................................................25
Calibration .........................................................................................26
Technical specifications .....................................................................27
Additional information required for testing ......................................28
Declarations.......................................................................................35
Servicing, maintenance and support .................................................36
Servicing....................................................................................................... 36
Support ........................................................................................................ 36
Part numbers and accessories...................................................................... 36
User Notes.........................................................................................37

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Safety and warnings
The 620 series will not present a safety risk when you use it as instructed in this User
Manual. However, it is possible that the environment where you use the instrument may
present a safety risk. For this reason, always follow correct, safe working practices.
WARNING
Always be aware of the risks in the environment where you are working.
•The 620 series is NOT intrinsically safe. DO NOT use it in an atmosphere
where explosive vapours or dusts might exist.
•Wear approved ear defenders when taking measurements in noisy
environments.
•Wear approved protective PPE suitable for the environment where you are
taking measurements.
•Always follow local safety regulations and be aware of risks in the area
where you are working.
CAUTION
The 620 series is a precision instrument. Always handle it with care. Do not drop
the instrument or subject it to mechanical shock.
Do not overtighten the microphone which should only ever be finger tight. Don’t
use pliers to tighten or undo the microphone should it become stuck.
CAUTION
The 620 series contains no user serviceable parts. If a fault is suspected, return
the instrument to Casella or a Casella approved service centre.
CAUTION
The 620 series operate from batteries (or optional mains power).
•Use only batteries of the correct type, and do not mix battery types in the
instrument.
•Do not try to charge non-rechargeable batteries.
•Do not leave discharged batteries in the 620 series.
•Install new batteries as a complete set. Do not fit batteries that have a
mixed state of charge.

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•Remove all batteries from the 620 series if you will not use the instrument
for a long time.
•Always follow local regulations to dispose of used batteries.
CAUTION
The 620 series is not waterproof. Do not immerse the instrument in water or use
it in the rain.
CAUTION
Care should be taken that the operator does not unduly affect the sound field.
Ideally the instrument should be mounted on a sturdy tripod with the microphone
perpendicular to the source of the sound to be measured and the operator should
be as far behind the instrument as possible. If the instrument is to be hand-held,
then the arm of the operator should be stretched out as far as possible to
minimise reflections from the operator’s body.
Disposal
WEEE Notice
At the end of the instrument’s life please do not throw away with the
unsorted municipal waste. Please recycle with a registered WEEE
handler.

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Disclaimer
Do not use the 620 series until you have thoroughly familiarised yourself with this manual or
have been instructed by a Casella engineer. A quick start guide will help you get started.
At the time of writing, this manual was up to date but due to continual improvements the
final operating procedures may differ slightly from those in the manual. If there are any
questions please contact Casella for clarification.
Casella makes continual advancements in its products and services. We therefore reserve
the right to make changes and improvements to any information contained within this
manual.
Whilst every care is taken to ensure that the information in this manual is correct, Casella
will assume no responsibility for loss, damage or injury caused by any errors in, or omissions
from, the information given.

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Introduction
The 620 series is a range of Integrating Sound Level Meters
designed to meet the demands of worldwide industrial health and
safety professionals as well as general noise measurement
applications fully compliant with international application and
instrument standards.
The 620 series is based on the very latest digital signal processing
(DSP) technology and has a colour TFT display with an intuitive user
interface. It encompasses functionality from basic sound level
measurement to integrating and real-time octave band analysis ,
the latter depending on the exact model.
Data is stored in a Comma Separated Variable (.csv) format,
compatible with Microsoft Office applications, and files may be
copied to a PC using a USB connection without the need for any
propriety software packages.
Instrument features
The 620 series comprises several variants, where the letters (A or B)
determine the model variant e.g. A for broadband and B for 1/1
octave band. A chargeable upgrade from A to a B model is
available. Models are available in Class 1 or Class 2 accuracy
signified by a number 1 or 2 (after the letter A or B). See Part
Numbers and Accessories later for more information.
Key features
The 620 series provides A, C, and Z frequency weightings, Fast Slow
and Impulse time weightings with cumulative storage and PC
connectivity functions. A single measurement range of 140dB RMS is standard. Simultaneous
LAeq and LCeq values are measured which may be used in the selection of hearing protection
using the HML method. Lavg (used in the US) is available with a selectable threshold.
New features for 2023
New features for 2023 include audio voice notes, time history profiling and GPS location.
Frequency analysis
‘B Models’provide integrating functionality combined with 1/1 octave band frequency
analysis. Advanced DSP processing provides fast parallel processing of octave band results
from 16Hz to 16kHz which may be displayed graphically or in numerical form and may be A,
C or Z frequency weighted.

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Controls
The 620 series has a compact, ergonomic and robust ‘rubber grip’ case design that fits
comfortably in the hand when not mounted on a tripod. Referring to figure 1 below, the
windshield (1) should be used at all times (except during Calibration) to cover and protect
the microphone, which is screwed onto the fixed pre-amplifier (2).
When the instrument is switched ON by pressing the red key (3) it will run through a
software initialisation and then default to a Stop mode, indicated by a Red Bar at the top and
bottom of the screen.
To navigate ‘within a screen’use the Cursor Keys (6) but note that not all the screens have
navigable fields.
To navigate from one screen to another, use the left and right hand Soft Keys (5).
To start a measurement ‘run’, press the Run/Stop Key (7); to stop the run press the same key
again.
The instrument has a single measurement range of 140dB (RMS) and 143.3dB (C) peak. No
range adjustment is needed which greatly simplifies operation.
The 620 series measures all combinations of required parameters simultaneously with the
required frequency and time weighting.
Figure 1

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Microphone and pre-amplifier
The 620 series has a fixed pre-amplifier and removeable ½ inch (12.7 mm) pre-polarised
microphone. There are two types of microphone available depending on the accuracy Class,
namely:-
•CEL-251 microphone used on Class 1 versions, 50 mV/Pa sensitivity
•CEL-252 microphone used on Class 2 versions, 30 mV/Pa sensitivity
The instrument is supplied with a microphone windshield which provides protection from
both wind and minor mechanical damage and should always be fitted to the microphone
(except during calibration).
Soft keys
The two soft keys (5) shown in figure 1 are located below the corresponding options
displayed at the bottom of each screen. The operation of these two keys change, depending
on which screen is displayed as shown by the overview of the operating system in figure 2.
Figure 2
Generally, you press the soft key on the right to select a function, and press the soft key on
the left to exit a screen or cancel a function.
The instrument screens have been designed with colour coded top and bottom bars to enable
the user to know at a glance which part of the operating system is currently being accessed.

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Colour coding in more detail is as follows in figure 3:
Screen
Colour
Description
Red
Stop screens –These screens are displayed when the instrument has
completed initialisation after power on, as well as before and after taking
measurements.
Blue
Settings screens –These screens are used to set up the instrument correctly
and includes settings such as date and time, language and backlight.
Light
Blue
Memory Results screens –This is where the results from measurements are
viewed.
Green
Run screens –These screens show a measurement is in progress, measured
values are stored in the memory results.
Yellow
Calibration screen –This screen is automatically displayed upon application
of a 1kHz Acoustic Calibrator. This is where the instrument is calibrated
before and after taking measurements.
Figure 3
Navigation keys
The four Navigation keys (6 in figure 1) allow you to select items when highlighted on the
main part of the screen.
Press the , , or navigation key to change to the next selection in the direction of
the cursor arrow.
Run/Stop key
The Run/Stop key (7 in figure 1) allows you to start and to stop a run manually (there is
also a timed run duration timer detailed later).
Connectivity
A rubber cover on the bottom of the instrument reveals an external 12V DC power inlet, USB
socket and Audio output socket described later.