3M 1100 SLM User manual

3M Occupational Health & Environmental Safety Division
1100/2100 Sound Level Meter Models
Functionality
1100/2100 SLM User Manual
Easy to Use

056-652, Rev.D 1100/2100 SLM models
1100/2100 Sound Level Meters
Owner’s manual
Introduction
The 1100 Sound Level Meter is a light weight easy-to-use Type 1 instrument. The
2100 is a Type 2 model.
The purpose of this manual is to provide you with the necessary information to operate
the 1100/2100 Sound Level Meter as well as the remote-able versions of the
1100R/2100R. The entire manual should be read to fully understand the many
features this instrument offers.
Copyright
This document is copyrighted by Quest Technologies, a 3M company. Permission is
hereby granted to copy and distribute this manual provided that this Copyright Page is
included. This grant does not include permission to modify the manual’s text or
illustrations in any way. This manual may not be translated without obtaining
permission in advance.
Trademarks
Quest Technologies, the Quest logo, and QuestSuiteTM Professional II are registered
trademarks of Quest Technologies Incorporated. All rights are reserved.
Microsoft and Windows are registered trademarks of Microsoft, Inc.
Updates
In the interests of continuous product improvements, Quest Technologies reserves the
right to make changes to product specifications without notice. To understand the
latest updates that have been implemented into this product and to download the most
current version of this user manual, visit our web site at www.quest-technologies.com.
Copyright © 2011 Quest Technologies, a 3M company
 Note:
Due to the new ATEX Directive in Europe, all
references in this document to "Ex" or "EEx" for intrinsic
safety approvals should be disregarded effective 7/1/03
within the member countries of the European Union (EU). At
this time, this product is not approved in accordance with the
new ATEX Directive and is not sold for use in hazardous
atmospheres or explosive zones by customers within the EU.
Outside of the EU, all references to intrinsic safety continue
without change.

Table of Contents
056-652, Rev.D 1100/2100 SLM models
ii
Table of contents
Introduction......................................................................................................................1
1100/2100 Models..............................................................................................................1
Getting Started .................................................................................................................3
The Display........................................................................................................................3
Meter Controls....................................................................................................................3
OFF/SPL/MAX Switch.....................................................................................................3
"F" (FAST) / "S" (SLOW) RESPONSE Switch..................................................................3
Overload Detection and Underrange ..................................................................................5
Output Jack........................................................................................................................5
DC Output Function.......................................................................................................5
AC Output Function ........................................................................................................5
Checking the battery........................................................................................................6
Battery Check.....................................................................................................................6
Battery Replacement..........................................................................................................6
Rechargeable Batteries......................................................................................................6
Calibrate............................................................................................................................6
Changing the Calibration Level...........................................................................................6
Calibration..........................................................................................................................7
Calibration Check...............................................................................................................7
Operating and Measurements .........................................................................................8
Operation ...........................................................................................................................8
Meter/Microphone Placement.............................................................................................8
Background Noise..............................................................................................................8
Background Noise Example ...............................................................................................9
Windscreen Effects.............................................................................................................9
Chart Recording/Datalogging ...........................................................................................10
Technical Information .................................................................................................... 11
Principles of Operation.....................................................................................................11
Microphone ......................................................................................................................12
Microphone response time ...............................................................................................12
Microphone preamplifier extension cables........................................................................13
Input Buffer Circuitry......................................................................................................... 13

Table of Contents
056-652, Rev.D1100/2100 SLM models
iii
Weighting Characteristics.................................................................................................14
Internal Electrical Noise.................................................................................................... 14
Tone Burst Response.......................................................................................................15
Specifications................................................................................................................. 16
Accessories.................................................................................................................... 18
Quest Service ................................................................................................................. 19
Contacting Quest Technologies........................................................................................ 19
International customers.................................................................................................... 19
Figures
Figure 1-1: Sound Level Meter 2100 model....................................................................1
Figure 1-2: Model 1100R/2100R....................................................................................2
Figure 2: Keypad/Control switches identified...............................................................4
Figure 3: Output jack connections...............................................................................5
Figure 4: Effects of background noise...........................................................................9
Figure 5: Effects of WS-7...........................................................................................9
Figure 6: Block diagram of the model 1100/2100’s circuit board..................................11
Figure 7: Typical microphone response Type 1 .........................................................12
Figure 8: Typical microphone response Type 2 .........................................................12
Figure 9: Frequency/Amplitude limitations with extension cables ................................13
Figure 10: Input buffer circuitry...................................................................................13
Figure 11: A & C Weighting........................................................................................14
Figure 12: Fast response...........................................................................................15
Figure 13: Slow response ..........................................................................................15

1Introduction
1100/2100 Models
056-652, Rev.D 1100/2100 SLM models
Introduction
The Quest models 1100 and 2100 Sound Level Meters and their remote versions
(1100R/2100R) measure frequency weighted and time averaged sound pressure
level and are shown in Figures l-1 and 1-2. Applications include laboratory,
industrial, community, military, and audiometric measurement or analysis.
1100/2100 Models
The models 1100 and 2100 are easy-to-use hand held meters with an LCD
display that provides a numerical readout. They are housed in a rugged RF
shielded, injection molded case. The meters are operated with simple slide
switches. An output jack is provided for connecting to peripheral devices such as
chart recorders, oscilloscopes, audio recorders, etc.
The model 1100 provides Type 1 accuracy for critical measurements, while the
model 2100 provides Type 2 accuracy for general field survey work. As both
meters are operationally identical, this manual will refer only to the model 1100
except where appropriate.
Figure 1-1: Sound Level Meter 2100 model
Contents
Introduction
Microphone
Fixed Preamp
Housing for the 1100 is longer than 2100
Display of the 2100 model

2Introduction
1100/2100 Models
056-652, Rev.D 1100/2100 SLM models
Figure 1-2: Model 1100R/2100R

3Getting Started
The Display
056-652, Rev.D 1100/2100 SLM models
Getting Started
The Display
The LCD display provides a numeric readout of sound level in 0.1 dB increments
along with a LOBAT (low battery) indicator. In the SPL mode the numeric display
provides a reading of the maximum sound pressure level measured during the
previous second. In the MAX mode the display
holds the highest reading encountered since the meter was placed in MAX, or
since the last time RESET was pressed.
The LOBAT indicator will light when the battery voltage is too low to allow an
accurate reading.
The display will show a + sign when signal peaks cause an overload condition in
the electronics. This indicator signals the user to switch to the next higher range to
prevent erroneous readings.
The display will show "Ur" if signal levels are too low to provide an accurate
reading. This indicator signals the user to switch to a lower range setting.
Meter Controls
OFF/SPL/MAX Switch
With the switch set to SPL the meter continuously displays sound level,
automatically updating the current reading at a rate of once per second.
Setting the switch to MAX causes the display to hold the highest SPL
encountered thus far. As a higher SPL occurs, the display changes to show
the new value. To reset the value stored, press and hold the RESET button
for a few seconds, then release. This will erase the previous MAX value
(and display the current value) prior to taking new readings. For response
times see Figures 7 and 8.
"F" (FAST) / "S" (SLOW) RESPONSE Switch
The RESPONSE switch controls the rate at which the meter responds to
changing input signals. Most sound measurements are done with the
response set to SLOW. The FAST response is generally used when
measuring short duration noises such as moving vehicles.
The RESPONSE switch positions are as follows:
•FAST - 125 millisecond time constant. (See Figure 12).
•SLOW - 1 second time constant. (See Figure 13).
Getting Started

4Getting Started
Meter Controls
056-652, Rev.D 1100/2100 SLM models
WEIGHTING A/C Switch
The WEIGHTING switch controls the frequency response of the meter.
Weightings A or C may be selected. See “Microphone preamplifier”, page
13 Weighting Characteristics, for further information.
RANGE (dB) Switch
The displayed range of the model 1100 is 70 dB and is switchable between
30-100 dB, 50-120 dB, and 70-140 dB. After switching ranges allow several
seconds for the meter electronics to stabilize.
RESET Button
This button is primarily used to clear the MAX sound level when the
instrument is in the MAX mode. Pressing the RESET button for at least a
half second will cause a reset of MAX. If observation of the changing Sound
Pressure Level is desired, while in the MAX mode, the RESET button may
be held down for as long as the SPL display is desired. Upon release of the
RESET button MAX will be reset and the 1100 will resume accumulating
MAX. The RESET button also functions as an up arrow during setup (see
“Changing the Calibration Level”, page 6).
CAL Button
This button is primarily used to enter the Calibration routine, but it also
functions as a down arrow during setup (see “Changing the Calibration
Level”, page 6).
Figure 2: Keypad/Control switches identified
Weighting
A or C
Response
Fast or Slow
Range
30 to 140 dBA
Measurement
SPL or MAX

5Getting Started
Overload Detection and Underrange
056-652, Rev.D 1100/2100 SLM models
Overload Detection and Underrange
The Overload Indicator is displayed whenever the incoming signal saturates
(overloads) the circuitry. It is the + sign on the left side of the display. If the
overload indicator is on while taking measurements in a Low range, increasing
the dB Range switch should cause the overload to disappear. If you are already
on the highest range setting and an overload condition still exists, the sound level
that you are measuring is beyond the capability of the 1100 due to either an
extremely high rms value or a high crest factor (peak to rms ratio).
Underrange is indicated by a "Ur" in the display. When the noise level drops
below the bottom of the range, this indicator will turn on. Switching to a lower
range will turn it off.
Output Jack
The model 1100 provides an output jack on the bottom of the meter for
measuring the weighted AC signal before the rms/log detector and the DC output
of that detector. This jack may be connected to any load without affecting the
operation of the meter. Connection to low impedance loads
will require correction for the 1 Kohm impedance of this output and will also
decrease battery life. The output jack uses a 3.5mm stereo plug.
Figure 3: Output jack connections
DC Output Function
The Sound Pressure Level (SPL) over the range selected is linearly
represented
by a DC output. The output changes 16.7mV/dB or 1 V/60dB. This output is
primarily provided for connecting a 0 to 1 volt span data recorder.
AC Output Function
This output provides the amplified, weighted AC signal from the input of the
RMS detector.

6Checking the battery
Battery Check
056-652, Rev.D 1100/2100 SLM models
Checking the battery
Battery Check
At any time other than initial turn on, if the LOBAT indicator on the display is
activated the user must replace the battery. A 9 volt Alkaline battery is
recommended for best performance. Refer to the label in battery compartment for
battery replacement.
Battery Replacement
Slide the battery door to the left to open the battery compartment and refer to the
label inside the compartment for proper battery orientation.
Rechargeable Batteries
Nicad type rechargeable 9 V batteries (such as Radio Shack® 23-299 7.2 V, 120
mAh) and an appropriate charger may be used with the 1100. The fact that nicad
9 V replacement cells typically operate at 7.2 V will be observed as shorter battery
life (approximately 8 hours with Radio Shack® 23-299). At the appearance of the
LOBAT indicator the nicad battery must be recharged. NiMH (Nickel-Metal-
Hydride) batteries are NOT recommended. This is due to the excessive discharge
of the typical NiMH cell prior to the voltage dropping low enough to activate the
LOBAT indicator.
Calibrate
Changing the Calibration Level
NOTE: There may be times when it is necessary to change the calibration level
that is stored in the meter. This calibration level is the decibel level that is
produced by your calibrator.
Changing Cal level
1. Turn on the meter. The display will show:
a. All segments for 2 seconds.
b. The meter revision number for 2 seconds.
c. The current calibration level stored in the meter for 5 seconds.
2. While current calibration level is in the display, press and hold both the
RESET and CAL buttons for at least 1/2 second or until dashes appear in
the display. Release the RESET and CAL buttons. The meter is now in the
calibration level set mode.
Battery &
Calibrate