ATP Instrumentation 8928 User manual

DIGITAL SOUND LEVEL METER
Model:8928
OPERATION MANUAL

1
INTRODUCTION
Your digital sound levelmeter
provides automatic ormanual ranging
4 measurement rangesfrom 40 to
130dB, and features0.1dB resolution.
The meter allowsyou to select
between fast andslow response
times as wellas A andC weighting.
A maximum holdfunction is provided.
Jacks on themeter provide AC
analog output.
Power on orpower off the
meter.
Auto range/ Manualrange
select key.
Record Maximum and
Minimum sound level
measurement.
A weighting andC
weighting select
key.
Response select key.
ON/OFF:
RANGE:
RECORD:
WEIGHTING A/C:
FAST/SLOW:
MAX HOLD:
Freeze Maximum
sound level reading.
BUTTON DESCRIPTION

MEASURING SOUND LEVELS
Sound levels aredisplayed both
digitally and ina bar graph.
The digital displayis updated every
160ms, while thebar graph isupdated
every 40ms.
1. Press theON/OFF key to turnthe
meter on. Theunit will firstdisplay
the full screenand "18:18.8" then
count down from99.9 to zero.
The meter willnow begin measuring
the current soundlevels.
SPL (Sound Pressure Levels)
appears on theleft side."A'',"dB"on
the right sideof screen.
Point the microphonetoward the
source of thesound to be
measured.
2
SPL
dB
+10
+0 +20 +30
90
REC MAX HOLD MIN
AUTO
MANU
SPL
BAT
FAST
SLOW
A C
dB
+10
+0 +20 +30
40
Diagram A
Diagram B
SELECTING THE RESPONSE TIME
You can select fastor slow response
time to suitdifferent applications and
standards.

3
For example, mostOSHA-related
testing is doneusing slow response
time and Aweighting.
When you turnthe meter on,it will be
in fast responsemode. Press the
FAST/SLOW key to togglebetween
fast and slowresponse.
AUTO
SPL
FAST
A
dB
+10
+0
40
+20 +30
AUTO
SPL A
dB
+10
+0
40
SLOW
+20 +30
Diagram C
Diagram D
A small FAST or SLOW will be
displayed on theright side ofthe
screen to indicatethe current mode.
SELECTING A AND C WEIGHTING
When you turnthe meter on,it will be
in A weightingmode.
A weighting enablesthe meter to
respond in thesame manner asthe
human ear,which increases and
decreases amplitude overthe
frequency spectrum. Applicationsfor
A weighting includeOSHA regulatory
testing, and theenvironmental
measurement, workplace design,and
low enforce-ment.

AUTO
SPL
dB
+10
+0
40
SLOW
C
+20 +30
C weighting issuitable for flat
response measurements withno
increase or decreaseof amplitude
over the frequencyspectrum.
Applications for Cweighting include
the sound levelanalysis of engines
and machinery.
Press the "WEIGHTING A/C" key to
select between Aand C weighting.
A small Aor Cwill be displayedon the
right side ofthe screen toindicate the
current mode.
Diagram E
4
FREEZING THE MAXIMUM SOUND
LEVEL READING
1. Press theON/OFF key to turnthe
meter on.
2. When measuringsound levels,
press the MAX HOLD key to freeze
the maximum reading.MAX HOLD
will be displayed.
The digital displaywill remain
unchanged until ahigher reading is
detected. Note thatthe bar graph
will continue torecord the current
reading.
3. Press theMAX HOLD key again to
exit maximum holdmode.

5
RECORDING THE MAXIMUM AND
MINIMUM MEASUREMENTS
1. Press theON/OFF key to turnthe
meter on.
2. Press theRECORD key. RECORD
REC will be displayedon the upthe
corner of thescreen. The meterwill
begintracking the maximum and
minimum sound level
measurements.
3. Press theRECORD key again.
MIN will appear on the middle up of
screenand the minimum sound
level measurement willbe
displayed.
The unit isnot recording atthis time
, but thebar graph willcontinue to
show the current reading.
MAX HOLD
AUTO
SPL
FAST
A
dB
+10
+0
40
+20 +30
Diagram F
REC
AUTO
SPL
FAST
A
dB
+10
+0 +20 +30
40
Diagram G
REC MIN
AUTO
SPL
FAST
A
dB
+10
+0 +20 +30
40
Diagram H

6
REC MAX
AUTO
SPL
FAST
A C
dB
+10
+0 +20 +30
40
4. Press the RECORD key again.
MAX will appear on screen side by
the "REC" andthe maximum sound
level measurement willbe
displayed. The unitis not recording
at this time,but th bargraph will
continue to showthe current
reading.
5. Press the RECORD key again to
resume recording andrepeat the
process.
6. Press and hold the RECORD key
until the RECORD indicator
disappears to exitrecording mode.
Diagram I
SELECTING AUTOMATIC AND
MANUAL RANGING
The meter features4 measurement
ranges in 10dBsteps:
40~70dB, 60~90dB, 80dB~110dB,
100dB~130dB.
When you turnthe meter on,it will be
in automatic rangemode and asmall
AUTO will be displayedon the left
side of thescreen. In thismode, the
meter will adjustthe measurement
range automatically foraccuracy.

The two digitnumber to theleft of the
bar graph onthe LCD willshow the
low end ofthe current range.
You can also setthe range manually.
MANU
SPL
FAST
A
dB
+10
+0 +20 +30
40
AUTO
SPL
dB
+10
+0
40
SLOW
C
+20 +30
Diagram J
Diagram K
7
The meter willbe able totake
readings more quickly, because the
unit does notneed to firstestablish
the range beforedisplaying the
measurement.
This is helpfulwhen you knowthe
measurement range inadvance.
Toadjust the rangemanually:
1. When measuring soundlevels,
press the RANGE keys as needed
to adjust themeasurement range.
MANU will appear onthe display.
Note that thetwo digit numbersto
the left ofthe bar graphwill change
to reflect thelow of thenewly
selected range.
2. Press RANGE key to switchback to
automatic ranging.

8
If the meteris operating inmanual
range and "LO" is displayed, the
sound is toolow or therange.
If "HI" is displayed,the sound istoo
loud.
In either case,you must adjustthe
measurement range oryour readings
will be inaccurate.
MANU
SPL
FAST
A
dB
+10
+0 +20 +30
100
Diagram L
MANU
SPL
FAST
A
dB
+10
+0 +20 +30
60
Diagram M
AUTOMATIC SHUTOFF
The meter willturn off automatically
after 20 minutesto preserve the
battery.
To override this feature:
1. Make surethe unit isturned off.
2. Press theON/OFF and MAX HOLD
buttons simultaneously.
3. When thefull display appears,
release the MAX HOLD button first,
" " will replaced full display.

9
CALIBRATION
Diagram N
4. Release theON/OFF key.
The meter will remain on until the
ON/OFF button is pressed again.
The automatic shutoff feature will
resume the next time the meter is
turned on.
Using a standardAcoustic Calibrator
(Recommend B&K type4231 model)
which generate "94dB"output.
1) Set whichevertime weighting :
Fast or Slow.
2) Set soundlevel range at:80~110
dB.
3) Select weightingA or C.
4) Max.Hold functionmeasurement
mode unenabled
5) Better tocalibrate under 60dB
sound environment.
Insert the microphoneinto the hole
of the calibrator. Press calibrator
ON/OFF key topower on, and
adjust the CALpotentiometer of
the unit, thelevel display will
indicate the desiredlevel.
While selecting Cweighting ,display
+/-0.3dB deviation isreasonable.

1
2
3
4
REPLACING THE BATTERY
When the screendisplay " BAT "down
at the left corner , the9V battery has
fallen to acritically low voltagelevel
and should bereplaced as soonas
possible. Use ascrewdriver to
unscrew the backbattery
compartment cover.Insert a fresh9V
battery and screwthe cover.
AUTO
SPL
BAT
FAST
A
dB
+10
+0 +20 +30
40
1. Calibration Adjustment(side)
By using a"+" screw driverto
adjust the calibration(Followthe
calibration instruction).
2. Analog outputjack ( side)
Connect to externaltest instrument
or to adatalogger , chartrecorder,
...for logging purposes.
3. Tripodmount
Mount the meterto a cameratripod
for increased stabilityand accuracy
, further eliminatehand or any
sound reflected fromthe user .
4. Battery compartment
By using ascrew driver toremove
the battery coveron the meter.
10
Diagram O

The meter conformsto the following
standards:
EN 50081-1/1992 :EN 55022
EN 50082-1/1997 :
(EN 61000-4-2/-3/-8,ENV 50204)
The meter complieswith the essential
protection requirements ofCouncil
Directive 89/336/EEC onthe approxi-
mation of thelaws of theMember
States relating toelectromagnetic
compatibility.
CE CERTIFICATION
11
RETURN AUTHORIZATION
Authorization must beobtained from
the supplier beforereturning items for
any reason. Whenrequiring a RA(
Return Authorization), pleaseinclude
data regarding thedefective reason,
the meters areto be returnedalong
with good packingto prevent any
damage in shipmentand insured
against possible damageor loss .
The meter iswarranted to be free from
defects in material and workmanship
for a periodof one yearsfrom the date
of purchase.
This warranty covers normal operation
and does notcover batteries, misuse,
abuse, alteration, tampering, neglect,
improper maintenance, or damage
resulting from leaking batteries.
Proof of purchase is required for
warranty repairs.
WARRANTY

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