BRUEL & KJAER Mediator 2238 Guide

Technical
Documentation
English BB1122–11
2238 Mediator
Integrating Sound Level Meter
Enhanced SLM Software BZ7125

August 1998
Brüel & Kjær BB1122–11
2238 Mediator
Integrating Sound Level Meter
Enhanced SLM Software BZ 7125

0–2 Brüel & Kjær2238 Mediator
User Manual
Trademarks
2238 Mediator is a trademark of Brüel & Kjær A/S.
Copyright © 1998, Brüel & Kjær Sound & Vibration Measurement A/S
All rights reserved. No part of this publication may be reproduced or
distributed in any form, or by any means, without prior consent in writ-
ing from Brüel & Kjær Sound & Vibration Measurement A/S, Nærum,
Denmark.

BB1122–11 0–3 2238 Mediator
User Manual
4
1
Contents
About this manual and the contents of the Enhanced module
Pushkey definitions
Explains how to set up parameters in the Measurement Set-up menu
Erasing bad data and setting a sequence to start automatically
Setting up print options and statistics data
Specifications for the Enhanced module
List of default parameters and interface error messages
Explains the programming of the interface jobs for the Enhanced
module
Introduction
2
Pushkey Definitions
3
The Measurement Set-up Menu
Measuring
5
Data Handling
6
Specifications
7
Appendix 1: General
8
Appendix 2: Interface

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User Manual
9Index

BB1122–11 1–1 2238 Mediator
User Manual
Chapter 1
Introduction
1.1 About this Manual.............................................................. 1–2
Summary of Contents........................................................ 1 – 2
About this Volume............................................................. 1 – 3
Detectors ............................................................................ 1 – 4
Statistics ............................................................................ 1 – 5
Back-erase.......................................................................... 1 – 5
Measurement Sequences................................................... 1 – 5
Aux 1................................................................................... 1 – 5
Aux 2................................................................................... 1 – 5
Measurement Set-up Menu .............................................. 1 – 6
1.2 Changing Application........................................................ 1 – 6
1.3 Measurement Parameters............................................... 1 – 6

Chapter 1 – Introduction
About this Manual
1–2 Brüel & Kjær2238 Mediator
User Manual
1.1About this Manual
1.1.1 Summary of Contents
●Chapter 1 – Introduction: provides a general overview
of the Enhanced module and its functions.
●Chapter 2 – Pushkey Definitions: provides informa-
tion about the pushkey functions for the Enhanced mod-
ule.
●Chapter 3 – Measurements Set-up Menu: gives in-
structions for setting up the measurement parameters
for the Enhanced module.
●Chapter 4 – Measuring: gives instructions for using the
back erase function and for starting a Measurement Se-
quence automatically.
●Chapter 5 – Data Handling: contains information about
the parameters that are saved in the Enhanced module,
the statistics data and how to set up the print options.
●Chapter 6 – Specifications: technical specifications for
the Enhanced module.
●Appendix 1 – General: lists the default parameters and
interface error messages that are specific for the En-
hanced module.
●Appendix 2 – Interface: gives instructions for using the
interface commands and queries for the Enhanced mod-
ule
●Index

Chapter 1 – Introduction
About this Manual
BB1122–11 1–3 2238 Mediator
User Manual
1.1.2 About this Volume
This volume of the User Manual deals only with the instruc-
tions and functionality that are specific for the Enhanced
module (Enhanced SLM Software BZ7125).
For information about the general operation and functionality
of Mediator please refer to the Basic User Manual (BZ 7126).
Conventions Used in this Manual
Pushkeys
References to buttons on the 2238 Mediator are shown with
the pushkey’s pictogram as it appears on the instrument (for
example ). Refer to section 2.1 for a complete list of button
pictograms and their functions.
Soft Keys
Mediator has two “soft keys” that have different functions
depending on the current context. The soft keys functions are
denoted by chevrons (<>) and courier type face. The current
functions of the soft keys are always shown on the display.
The soft key can have the following functions: <Select>,
<Save>, <Ok> or <Menu>. The soft key can have func-
tions: <Cancel>, <Undo> or <Close>. They can also have
functions: <Freq W.> or <Time W.> respectively, depending
on the selected parameter in the Measurement Window. This
is similar to the functionality from the familiar Windows
environment.
Parameter Text
Text which refers directly to text on the instrument’s screen
or printouts is indicated using a Courier type face.
For example: Press until Language is highlighted in the
System menu.
Sockets
Reference to sockets is made in bold type face (for example,
Aux 1).

Chapter 1 – Introduction
About this Manual
1–4 Brüel & Kjær2238 Mediator
User Manual
1.1.3 Detectors
One of the main features of the Mediator is that it contains
two detectors with independent frequency weighting func-
tions, see Fig. 1.1. In the Enhanced module, one is an RMS
detector and the other can be set up to measure RMS or Peak.
This allows, for example, simultaneous measurement of A-
and C-weighted RMS and to measure and display the differ-
ence between two RMS parameters directly (for example, LCeq
– LAeq).
Fig.1.1 Simplified block diagram for 2238 Mediator
L-filter MUX Aux 1
Aux 2
A-filter
C-filter
Overload detector
1/1- and 1/3-Octave
Filter Set
Correction filter
(Sound Incidence,
Windscreen)
Amplifier
10 dB/step
(Cal. adjustment)
Preamplifier
MUX
Buffer
AC out
RMS
detector
Time weighting
Buffer
DC out
Peak/RMS
detector
Digital control
and processing
Power supply
Display
Keys
Microphone
RMS 1 RMS 2 PEAK AUX1/2
External
power
supply
980362e
Batteries 6V
(4 x AA size)
Serial
interface

Chapter 1 – Introduction
About this Manual
BB1122–11 1–5 2238 Mediator
User Manual
Linear and A- and C-weighting can be selected for both de-
tectors. F (Fast), S (Slow) and I (Impulse) time weighting are
available simultaneously in both RMS detectors, making it
possible to measure up to six combinations at the same time.
1.1.4 Statistics
The Enhanced module provides level and cumulative distri-
butions and can display up to seven LNvalues which you can
set up from your own choice (LNis the percentile level ex-
pressing the level that has been exceeded for N% of the
measurement time). All statistics are saved with the meas-
urement.
1.1.5 Back-erase
The back-erase function allows you to delete up to the last
15 seconds of the current measurement. This is particularly
useful if a disrupting noise occurs during a measurement.
1.1.6 Measurement Sequences
Automatic Measurement Sequences makes it easy to generate
periodic reports. You can set up Measurement Sequences with
up to 99 automatic measurements.
1.1.7 Aux 1
In addition to the AC Output function in the basic version,
Aux 1 can be set up as a DC input for an external signal.
1.1.8 Aux 2
In addition to the DC Output function in the basic version,
Aux 2 can be set up as a DC input for an external signal, a
trigger input or a trigger output.

Chapter 1 – Introduction
Changing Application
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1.1.9 Measurement Set-up Menu
The Measurement Set-up menu contains the following items
in the Enhanced module:
●General (for setting the measurement range, the Peaks
Over level and the 2nd exchange rate)
●Weightings (for setting the frequency weightings for
Detector 1 and 2)
●Statistics (for setting up the LNvalues and time weight-
ing)
●Measurement Control (for setting up measurement se-
quences)
●Correction Filters (for selecting correction filters for
sound incidence and windscreen)
●Input/Output (for setting up the Aux 1 and Aux 2 sock-
ets)
●Auto Start (for selecting an Auto Start)
●Occupational Health (for setting up the Occupational
Health parameters)
●Save Setup (for saving a measurement set-up)
●Recall Setup (for recalling a measurement set-up)
1.2 Changing Application
Push the key to display the System menu from which
you can select the desired application module.
1.3 Measurement Parameters
Table 1.1 lists the discrete parameters available with the
Enhanced module. The X and Y suffixes in the parameter
names refer respectively to frequency weightings (A, C or L)
and time weightings (S, F or I).

Chapter 1 – Introduction
Measurement Parameters
BB1122–11 1–7 2238 Mediator
User Manual
Detector 1 — RMS Parameters
Parameter Default screen
parameter Definition Freq.
Weight-
ing
Time
Weight-
ing
LXeq LAeq Equivalent continuous
level for the duration of
the measurement as
defined by IEC1672
“A”, “C”
or “L” –
LXIeq LAIeq Equivalent continuous
level of the impulse
weighted SPL
“A”, “C”
or “L” “I”
LXYav4 LAFav4 Averaged sound level
with an Exchange Rate of
4dB(LDOD)
“A”, “C”
or “L” “F” and “S”
LXYav5 LAFav5 Averaged sound level
with an Exchange Rate of
5dB(LOSHA)
“A”, “C”
or “L” “F” and “S”
LXE LAE Frequency weighted
sound exposure level for
the duration of the meas-
urement as defined by
IEC1672
(SEL, 1s)
“A” –
LXep,d LAFep,d Daily Personal Noise
Exposure.Recommended
by EEC Directive EEC/86/
188
“A” –
EAEA Total sound exposure for
the duration of the meas-
urement in Pa2h
––
LXYmax LAFmax Max. LXYp value detected
within the elapsed time “A”, “C”
or “L” “F”, “S” and “I”
LXYmin LAFmin Min. LXYp value detected
within the elapsed time “A”, “C”
or “L” “F”, “S” and “I”
Table 1.1 Parameters available with the Enhanced module

Chapter 1 – Introduction
Measurement Parameters
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LXYp LAFp Sound pressure level
(display only) “A”, “C” or “L” “F”, “S” and “I”
LXYinst LAFInst Randomly sampled
instantaneous value of
RMS level (display only)
“A”, “C”
or “L” “F”, “S” and “I”
LAFT5 LAFT5 “Taktmaximal” “A” “F”
LAFTm5 LAFTm5 Averaged “Taktmaximal” “A” “F”
Detector 1 general – other parameters
LXYN LAF1 ...
LAF99 Percentile levels “A”, “C” or “L” “F”, “S” or “I”
Level distribu-
tion – Level and cumulative dis- tribution ––
LAIeq–LAeq LAIeq –
LAeq Impulsiveness “A” –
LAFTm5–LAeq LAFTm5–
LAeq “Impulszuschlag” “A” –
LCeq–LAeq LCeq–
LAeq Evaluation of low fre- quency contents “C” and “A” –
Dose%XADose The dose percentage
based on the LXeq (3dB
exchange rate)
“A” “F” or “S”
Dose%XY4 AFDose4 The dose percentage
based on the Lav and a
4dB exchange rate
“A” “F” or “S”
Dose%XY5 AFDose5 The dose percentage
based on the Lav and a
5dB exchange rate
“A” “F” or “S”
Overload% Over-
load% The percentage of time that an overload occurred
during a measurement
––
Table 1.1 (cont.) Parameters available with the Enhanced module

Chapter 1 – Introduction
Measurement Parameters
BB1122–11 1–9 2238 Mediator
User Manual
Underrange% Under-
range% The percentage of time that an underrange
occurred during a meas-
urement
––
Elapsed Time Elapsed
Time The amount of time that has passed since the cur-
rent measurement began
(measurement time
excluding pauses)
––
Start Time Start
Time The start time for the cur- rent measurement ––
Start Date Start
Date The start date for the cur- rent measurement ––
Time Time The current time – –
Detector 2 — RMS Parameters
LXeq LCeq Equivalent continuous
level for the duration of
the measurement as
defined by IEC1672
“A”, “C”
or “L” –
LXIeq LCIeq Equivalent continuous
level of the impulse
weighted SPL
“A”, “C”
or “L” “I”
LXYmax LCFmax Max. LXYp value detected
within the elapsed time “A”, “C”
or “L” “F”, “S” or “I”
LXYmin LCFmin Min. LXYp value detected
within the elapsed time “A”, “C”
or “L” “F”, “S” or “I”
LXYp LCFp Sound pressure level
(display only) “A”, “C” or “L” “F”, “S” or “I”
LXYinst LCFInst Randomly sampled
instantaneous value of
RMS level (display only)
“A”, “C”
or “L” “F”, “S” or “I”
Table 1.1 (cont.) Parameters available with the Enhanced module

Chapter 1 – Introduction
Measurement Parameters
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Note 1: It is not possible to select the same frequency weight-
ing (A, C or L) for both detectors when they are both set to
RMS.
Note 2: If the Aux 1 or Aux 2 socket is used for input, the
signal(s) can be displayed and stored.
Detector 2 — Peak Parameters
LXpk LCpk Instantaneous peak level “C” or
“Lin.” –
LXpkmax LCpkmax Max. Peak level detected
during the measurement “C” or “Lin.” –
Number of
Peaks #cPeaks Counts the number of seconds where a speci-
fied peak level is
exceeded during a meas-
urement
“C” or
“Lin.” –
Table 1.1 (cont.) Parameters available with the Enhanced module

BB1122–11 2–1 2238 Mediator
User Manual
Chapter 2
Pushkey Definitions
2.1 Pushkey Definitions........................................................... 2–2

Chapter 2 – Pushkey Definitions
Pushkey Definitions
2–2 Brüel & Kjær2238 Mediator
User Manual
2.1 Pushkey Definitions
Each pushkey on the sound level meter’s front panel is
marked with a pictogram. This section gives a brief explana-
tion of the buttons.
Power Press this key to switch the instru-
ment on or off. The instrument will
be in pause mode when started up.
Calibrate Press this key to calibrate your in-
strument.
System Press this key to display the Sys-
tem menu for configuring the in-
strument and for changing
application programs.
Data Files Press this key to select the Data
Files menu. The menu options in
this window allows you to save,
print and edit printout files and to
access the File Manager facility.
Set-up Press this key to access/step
through the set-up options in the
Measurement Set-up menu.
Up/Down Arrows Press these keys to step up/down
in the menu items in the selected
window. Also for entering/exiting
edit mode in the Measurement
Window.
Left/Right Arrows Press these keys to select the pa-
rameters in the selected window.
Note: For the sake of consistency
the keys are always used
to select menu items, and the

Chapter 2 – Pushkey Definitions
Pushkey Definitions
BB1122–11 2–3 2238 Mediator
User Manual
keys are always used to se-
lect values.
Range Press this key to access the Range
Setting menu. Use the
keys to step through the available
measurement ranges or scroll with
the key.
Reset Resets the current measurement
data and sets the buffer and timer
to zero. If a measurement is in
progress, it will continue immedi-
ately after reset. If the instrument
is paused, it will still be paused
after pressing Reset.
Note: If a measurement has been
in progress for more than a minute
a warning is displayed and you
must confirm the command before
any data is deleted.
Meas. Results Press this key in any of the set-up
menus to return to the Measure-
ment Window. If menu changes
have not been saved, they will be
cancelled.
Pause/Continue Press this key to pause/continue
the current measurement. If the
sound level meter is in pause mode,
the measurement is continued
without resetting data or the timer.
Select Softkey with functions <Select>,
<Save>, <Recall> or <Ok> de-
pending on the cursor position in
the current menu. The <Menu>
function displays the File Manager
Options Window.
0

Chapter 2 – Pushkey Definitions
Pushkey Definitions
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Cancel Softkey with functions <Cancel>,
<Undo> or <Close> depending on
the cursor position in the current
menu.
Backlight Switches the display’s backlight on
or off. To save batteries, the back-
light switches off automatically af-
ter 30 seconds.
In addition to the functionality of the Basic module, the fol-
lowing pushkeys have added functions in the Enhanced mod-
ule:
Meas. Results Activates the Back-erase Window if
the Measurement Window is dis-
played and Mediator is paused.
Freq. W. The <Freq. W.> function selects
the frequency weighting parameter
in the Measurement Window.
Time W. The <Time W.> function selects
the time weighting parameter in
the Measurement Window.