Simpson 897 User manual

OFF RUN HOLD LOCK
SIMPSON ELECTRIC CO. ELGIN , IL 60120
897 DOSIMETER
SOUND MEASURING SYSTEM
SPL
"CAL"
INT
(60 sec)
DOSE
PEAK
Leq
MAX
TIME PRINT
TEST SETUP
12
3
4
5
6
7
8
9
LO BATT
SPL MAX
INT 60s
% DOSE
dBA
Model 897
Dosimeter Sound Measuring System
OPERATOR’S MANUAL

2
About this Manual
To the best of our knowledge and at the time written, the information contained in
this document is technically correct and the procedures accurate and adequate
to operate this instrument in compliance with its original advertised specifica-
tions.
Notes and Safety Information
This Operator’s Manual contains warning symbols which alert the user to check
for hazardous conditions. These appear throughout this manual where appli-
cable, and are defined below. To ensure the safety of operating performance of
this instrument, these instructions must be adhered to.
!
Warning, refer to accompanying documents.
Caution, risk of electric shock.
This instrument is designed to prevent accidental shock to the operator when
properly used. However, no engineering design can render safe an instrument
which is used carelessly. Therefore, this manual must be read carefully and com-
pletely before making any measurements. Failure to follow directions can result
in a serious or fatal accident.
!
Technical Assistance
SIMPSON ELECTRIC COMPANY offers assistance Monday through Friday
8:00 am to 4:30 pm Central Time. To receive assistance contact Technical Sup-
port or Customer Service at [phone].
Internet: http://www.simpsonelectric.com
Warranty and Returns
SIMPSON ELECTRIC COMPANY warrants each instrument and other articles
manufactured by it to be free from defects in material and workmanship under
normal use and service, its obligation under this warranty being limited to making
good at its factory or other article of equipment which shall within one (1) year
after delivery of such instrument or other article of equipment to the original
purchaser be returned intact to it, or to one of its authorized service centers, with
transportation charges prepaid, and which its examination shall disclose to its
satisfaction to have been thus defective; this warranty being expressly in lieu of
all other warranties expressed or implied and of all other obligations or liabilities
on its part, and SIMPSON ELECTRIC COMPANY neither assumes nor autho-
rizes any other persons to assume for it any other liability in connection with the
sales of its products.
This warranty shall not apply to any instrument or other article of equipment
which shall have been repaired or altered outside the SIMPSON ELECTRIC
COMPANY factory or authorized service centers, nor which has been subject to
misuse, negligence or accident, incorrect wiring by others, or installation or use
not in accord with instructions furnished by the manufacturer.

3
NOTES

4
Contents
1. INTRODUCTION ............................................................................... 7
1.1 General Description ........................................................................... 7
1.2 Items Furnished With Instrument ........................................................ 7
1.3 Technical Data .................................................................................... 8
2. PREPARATION FOR USE ............................................................... 11
2.1 Unpacking And Inspection ............................................................... 11
2.2 Preparation For Use .........................................................................11
2.3 Warranty ...........................................................................................12
2.4 Shipping ...........................................................................................12
3. APPLICATION ................................................................................. 12
3.1 Decibel Scale ...................................................................................12
3.2 Sound Level Meter ...........................................................................12
3.3 Measurement And Exposure Standards ..........................................13
3.3.1 Steady Level or Slowly Varying Noise ............................................. 13
3.3.2 Impact Noise .................................................................................... 15
3.4 Dosimeter .........................................................................................15
3.5 Dosimeter Equation ..........................................................................15
3.6 Sound Fields ....................................................................................16
3.6.1 Free Field .......................................................................................... 16
3.6.2 Reverberant Field ............................................................................. 16
3.7 Microphone Orientation ....................................................................16
3.7.1 Area Monitor in a Free Field ............................................................. 16
3.7.2 Fixed Position Monitor in a Reverberant Field ................................. 16
3.7.3 Use of Dosimeter as a Personal Monitor ........................................ 16
3.8 Windscreen .......................................................................................17
4. OPERATION .................................................................................... 17
4.1 Safety Precautions ...........................................................................17
4.2 Operating Items And Features .........................................................17
4.3 Top Panel Operating Features ........................................................19
4.4 Battery Charging ..............................................................................19
4.5 Preliminary Checks ..........................................................................20
4.5.1 Underrange Display ......................................................................... 20
4.5.2 Overrange Display ........................................................................... 20
4.5.3 Diagnostic Memory Test .................................................................. 20
4.6 Setting The Dosimeter Parameters ..................................................21
4.6.1 The Dosimeter Parameters ............................................................. 21
4.6.2 To Program the Dosimeter ............................................................... 21
4.7 Security Controls ..............................................................................23
4.8 Selection Of Parallel Or Serial Output Format .................................23
4.9 Automatic Data Logger .....................................................................23
4.10 Data Output Formats ........................................................................24
4.11 Parallel Output And Serial Format 2 “Prn 2” ....................................24
4.12 Spreadsheet Output Format “Prn 1” .................................................26
4.13 Calibration ........................................................................................27
4.14 Dosimeter Application ......................................................................28
4.15 Error Message ..................................................................................30

5
NOTES

6
NOTES

7
1. INTRODUCTION
1.1 General Description
The Simpson Model 897 is a combination dosimeter and Class S2A sound level
meter. It is a portable, easy-to-operate, accurate digital sound measurement in-
strument designed to meet the requirements of OSHA and international noise
exposure regulations.
The 897 has a built-in data logger with a 31 hour storage capability. There are two
standard output formats available with the data logger, a Centronics compatible
parallel printer and an RS-232C serial printer or computer. The 897 also meets
the requirements for the American National Standard Institute (ANSI) Specifica-
tion S1.4-1983 and IEC651 for class S2A sound level meters and American
National Standard Institute (ANSI) Specification S1.25-1978 for Personal Noise
Dosimeters.
Measuring continuous, intermittent and impulsive noise in the standard range
from 80 dBA to 130 dBA, the 897 also offers a 50 to 100 dB range where lower
sound level analysis is desired. When used as a personal noise dosimeter, the
897 may be worn in a shirt pocket or on a belt. The microphone is provided with a
clip which can be attached to the operator’s shirt close to the ear.
When used as a sound level meter, the Instrument is hand-held. A front end
attachment, properly contoured to avoid interference with incoming sound waves,
holds the microphone. The advanced microcomputer, large digital display and
special electret-condenser microphone offers easy operation and readability,
and excellent performance and reliability.
1.2 Items Furnished With Instrument
All items furnished with the 897 are listed in Table 1-1.
Table 1-1. Items Furnished with the Instrument
.oNtraPnoitpircseDytQ
1 Windscreen Dust Cover 5-119753
1 Microphone Clip 5-119752
1 Splined Wrench 6-113274
1 Screwdriver, adjusting 5-116470
1 Microphone Adapter 10-865235
1 Operator’s Manual 6-115891
1 Parallel Cable 02234
1 AC Charger 6-115095
1 Carrying Case 10-865926
Optional Items
Part No.Description
887-2 Sound Level Calibrator 12648
RS-232 Serial Cable 02233
1

8
1.3 Technical Data
The 897 conforms to ANSI S1.4-1983, ANSI S1.25-1978, and IEC651 (1979)
standards for type S2A sound level meters and noise dosimeters.
Table 1-2 lists the technical specifications for the 897 Noise Dosimeter/Sound
Level Meter.
Table 1-2. Instrument Specifications
Dosimeter Specifications
1. Microphone:
Type: 0.52 inch (13.2 mm) diameter electret con-
denser.
Maximum Pressure: 148 dBA sound pressure level.
Impedance: 1 K⍀
Directional Characteristics: Omnidirectional. The free field angle of inci-
dence which closely approximates the ran-
dom response is 70°.
2. Threshold Level: The threshold level is selectable over the
range of 50 to 99 dB, in 1 dB increments,
from the front panel. The dosimeter function
of the 897 is nonresponsive to noise levels
below the threshold setting.
3. Dose:
Resolution: 0.1% dose to 999.9%; above 1000%, dis-
play will automatically convert to a higher
range.
Maximum Indication: Dual automatic ranging: either 999.9% or
9999%. 100% corresponds to a criterion
level noise exposure for eight hours; 50%
corresponds to an eight hour noise expo-
sure equal to the criterion level minus the
exchange rate.
4. Leq Display: Displays with 0.1 dB resolution. Selectable
upper limit of 115 or 130 dB.
5. Criterion Level: Selectable at 70, 80, 84, 85 or 90 dB from
the front panel.
6. Exchange Rates: 3, 4 or 5 dB, selectable from the front panel.
7. Elapsed Time: Displays either hours:minutes or
minutes:seconds, up to 99 hours, 59 min-
utes, 59 seconds. Timing accuracy: 6 0.05%.
8. Dynamic Range: Two switch selectable ranges, 50 to 100 dB
and 80 to 130 dB.
9. Accuracy: True RMS, per ANSI S1.4-1983, type S2 re-
quirements.
10. Frequency Response
Weighting: “A” weighting.
11. Response Time: Slow (1 second).
12. Crest Factor: 10:1 at maximum indication.
13. Frequency Range: 31.5 Hz to 8 KHz.
14. Sound Pressure Reference: 0 dB = 20 μ Pascals.
15. Linearity: 60.5 dB @ 1 KHz: 50/100 Range: >60dB; 80/130 Range: >90dB
16. Criterion Duration (Tc): 8 hours.

9
17. Calibration: Instantaneous with 100 Hz, 94 dB or 114 dB
SPL calibrator and adjustment on the top of
the 897. However, an annual factory
recalibration is recommended.
18. 140 dB Peaks: Front panel selectable display indicates
number of 140 dB peaks that have been de-
tected.
19. Warm-up Time: One minute.
20: Data Logger
Recording Time: 31 hours maximum. Any data beyond this
time is not stored; only the first 31 hours
are retained.
Stored Information: a. The integrated 60 second average
(LAVG).
b. The highest SPL (Lmax).
c: The number of detected 140 dB peak
occurrences.
d: “HOLD” switch status.
e: “RANGE” switch status.
Storage Rate: Data is stored at 00:01:00 (hrs:min:sec) and
once per minute thereafter.
Data Retention: Data is retained for as long as the unit re-
mains powered in the “RUN” or “HOLD”
modes; all data is lost in the “OFFf” mode.
However, to minimize the chance that data
may be lost inadvertently, the data is retained
for 3 seconds after the power is turned off.
Data Output Port:
ynahtiwsetacinummoc,elbacdeilppushtiW:lellaraP
Centronics compatible, 80 column printer.
RS-232C Serial: With accessory cable, catalog #02233, com-
municates with any serial computer port at
baud rates of 300, 600, 1200, 2400, 4800 or
9600. (Serial port set for 8 bit words, no par-
ity, 1 stop bit). It will also function with many
RS-232C serial printers.
Data Output Format:
,leveldlohserht,levelnoiretircsedulcnI:lellaraP
elapsed run time, elapsed hold time, Leq,
SPL MAX, dose, and number of 140 dB
peaks. A five minute average level
histograph is then output, which addition-
ally gives indications of the RANGE switch
setting and activation of “HOLD” mode. This
is then followed by a complete listing of all
stored information on a minute-by-minute
basis. See para. 4:10 for further details.
-xe,leveldlohserht,levelnoiretircsedulcnI:laireS
change rate, unit identification number,
elapsed hold time. Leq, SPL MAX, dose, and
number of 140 dB peaks. This is then fol-
lowed by a complete listing of all stored in-

10
formation on a minute-by-minute basis. All
of this data is formatted either for convenient
input to a spreadsheet program, such as
Microsoft Works 3.0 for DOS, or in the same
format as the parallel printer.
Real-Time Clock: A real-time clock provides time and date in-
formation on the printout. The clock contin-
ues running even with power “OFF”.
21. Power Requirements: The 897 is designed to be used with the
Simpson battery charger, part number 6-
115095, which is adequately insulated to
permit use of the 897 while being charged.
This charger has a rated input of 108 V AC to
264 V AC at 50/60 Hz. Use of any other
charger may be hazardous to the operator
or to the 897.
Internal Rechargeable
Nickel-cadmium Battery Pack: Rechargeable with supplied recharger.
Battery Life: Approximately 40 hours between charges in
“RUN”. Approximately 60 hours between
charges in “HOLD”.
NOTE: When the Instrument is switched to “RUN” and the display shows “ERR3”
and “LO BATT”, the battery must be charged at least 8 hours.
Low Battery Indicator: Automatically displays “LO BATT” to indicate
at least eight hours of time remaining.
22. Display 4-digit liquid crystal display with six additional
characters: SPL, SPL MAX, INT 60, LO BATT,
% DOSE, dBA, plus a colon and decimal
point.
23. Keyboard Selected Functions:
SPL(CAL): Sound Pressure Level
INT (60 Sec): Continuous 60 second integrated SPL (also
referred to as LAVG.).
DOSE: In percent.
PEAK: The number of detected 140 dB peaks, up to
a maximum of 250.
Leq: The eight-hour Time Weighted Average.
MAX: The maximum detected SPL.
TIME: Displays elapsed HRS:MIN or MIN:SEC.
PRINT: Activates the Data Output.
24. Mechanical Construction
Security Provisions: “Special” (#4 spline) wrench provided to lock
“OFF-RUN-HOLD” slide switch into any po-

11
sition. A keyboard switch “lockout” feature
allows the 897 to be locked into any desired
function.
Case Construction: Anodized aluminum extrusion.
Physical Dimensions:
Length: 6.8 inches (172 mm)
Width: 3.1 inches (80 mm)
Thickness: 1.1 inches (28 mm), excluding microphone
and clip.
Weight: 18 oz. (500 gm)
25. Environmental Specifications
Temperature:
Influence: 60.03 dB/°C, -10 to +25°C, 60.05 dB, +25 to
50°C (Reference 1000 Hz and 105 dB).
Operating Range: -10 to 50°C.
Storage Range: -30 to 45°C (limitation of batteries).
Humidity:
Influence: Less than 0.5 dB over measurement range.
Range: 0 to 95% RH.
Magnetic Field: No effect when placed in a field of 1 oersted
(80 A/m) with Model 897 oriented for maxi-
mum sensitivity to the field.
Atmospheric Pressure: Correction data is provided in the calibrator’s
operator’s manual.
2. PREPARATION FOR USE
This section contains instructions for preparing the new Instrument for use. Also
included are unpacking and inspection procedures, warranty and shipping in-
structions.
2.1 Unpacking And Inspection
Examine the shipping carton and Instrument for damage. If undamaged, check
for internal damage . (Preliminary checks of the operating condition of the Instru-
ment can be made after carefully reading Section 4). If there is external or internal
damage, immediately file a complaint with the carrier. Make certain all items in
Table 1-1 are included in shipment. Save the shipping carton for possible future
shipping of the Instrument.
NOTE: The 897 is powered by a self-contained rechargeable nickel cadmium
battery pack. Charge Instrument for 16 hours before use.
2.2 Preparation For Use
Accuracy of measurements can be affected by several factors, including the po-
sition of the microphone with respect to the sound source and the positioning of
the microphone on the user. Read Section 3 carefully for general background
information.
In operation, the Instrument can be attached to the belt with the clip provided, or
can be placed in the shirt pocket. Ideally the microphone should be clipped

12
upright to the shirt on the center of the shoulder. If this is impractical, clip the
microphone facing upward on the shirt collar. To protect the microphone in dusty
or windy environments, place the windscreen over the microphone before at-
taching it to the shirt.
2.3 Warranty
The Simpson Electric Company warranty policy is printed on the inside front
cover of this manual. Read it carefully before requesting warranty repairs. For all
assistance, including help with the Instrument under warranty, contact the factory.
Give full details of any difficulty and include the Instrument model number and
date of purchase. Shipping instructions will be mailed promptly. If an estimate of
charges for nonwarranty or other service work is required, a maximum charge
estimate will be quoted. This charge will not be exceeded without prior approval.
2.4 Shipping
Pack the Instrument carefully and ship it prepaid and insured to the proper desti-
nation.
3. APPLICATION
This section contains the basic information required for effective application of
the 897. To understand the operation of the Instrument, the following paragraphs
discuss its function in relation to some of the subtleties of sound.
3.1 Decibel Scale
The human ear has a sound sensitivity range of greater than one million to one,
from the lowest level that can be detected to the highest level that can be toler-
ated without pain. Because of the large ratio involved, a linear meter scale marked
in sound pressure units becomes impractical. A scale based on logarithms, called
a decibel (dB) scale, is used. This scale expresses the ratio between the sound
pressure level being measured, with respect to a reference level and converts
large ratios into smaller convenient numbers. For example, a million-to-one pres-
sure ratio can be compressed on a 0 to 120 dB scale. The zero dB is the low limit
reference which the human ear can barely perceive.
3.2 Sound Level Meter
A sound level meter is a measuring device used to determine the existing sound
pressure level in a particular area. A choice of frequency responses called A, B
and C “weightings” is typically provided which relate to the human ear response
at low, middle and high sound pressure levels. The sound pressure level is ex-
pressed in dB A, dB B or dB C where 0 dB = 20 μ Pascals; the threshold of hearing
and the A, B and C define the “weighting” selected. (See Figure 3-1).
NOTE: All OSHA type sound level meters must be A-weighted. B and C weightings
are not required for compliance measurements.
The sound level meter function of the 897 meets the requirements of the Ameri-
can National Standards Institute (ANSI) Standard Specification S1.4 1983 for
type S2A (“A” weighted) general purpose sound level meter.

13
3.3 Measurement And Exposure Standards
Sound level meter measurement standards are defined in American National
Standards Institute (ANSI) Specification S1.4-1983. Federal, State and local gov-
ernments also have defined allowable noise (undesirable sound energy) level
exposure limits for persons in industrial environments. Selected and applicable
parts of those currently in force are cited in this manual.
NOTE: Standards and government regulatory laws are subject to modification or
expansion. Always check for latest available documents and information.
The Occupational Safety and Health Act of 1970 (OSHA), The Walsh-Healy Act
(Federal Register, Vol. 34, No. 96) and paragraph 1910.95 of the Occupational
Safety and Health Standards (Federal Register, Vol. 46, No. 162), set the present
legal standards of allowable employee noise exposure limits and are shown in
Tables 3-1 and 3-2.
3.3.1 Steady Level or Slowly Varying Noise
Table 3-1. Permissible Noise Exposure Limits
(Based on 90 dB criterion level and 5 dB exchange rate)
Duration Per Day Sound Level, dB A
in Hours SLOW Response
8 90
6 92
4 95
3 97
2 100
1 - 1/2 102
1 105
1/2 110
1/4 or less 115
0
–5
–10
–35
–30
–15
–20
–25
–40
–45
–50
+5
20 50 100 200 500 1000 2000 5000 10,000 20,000
FREQUENCY RESPONSES
FOR SLM WEIGHTING
CHARACTERISTICS
FREQUENCY (Hz)
RELATIVE RESPONSE DECIBELS
B AND C
A
C
B
A
Figure 3-1. A, B & C Weighted Electrical Responses

14
noitaruD
yaDreP
sruoHni
leveldnuoS
ABd
esnopserwolS
noitaruD
yadrep
sruohni
leveldnuoS
ABd
esnopserwolS
23 0878.0601
9.72 1867.0701
3.42 2866.0801
2.12 3875.0901
4.81 4805.0011
00.61 5844.0111
39.31 6883.0211
21.21 7833.0311
65.01 8892.0411
91.9 9852.0511
00.8 0922.0611
69.6 1991.0711
60.6 2961.0811
72.5 3941.0911
95.4 49521.0021
00.4 5911.0121
84.3 69590.0221
30.3 79280.0321
46.2 89270.0421
03.2 99360.0521
00.2 001450.0621
47.1 101740.0721
25.1 201140.0821
23.1 301630.0921
51.1 401130.0031
00.1 501
Varying Level Noise
When daily noise exposure is composed of two or more periods of noise expo-
sure at different levels, consider their combined effect rather than the individual
effect of each. The total dose is computed by the expression:
Where: D is the noise dose; C1, C2 … Cn are the actual segments of exposure
time at different noise levels; and T1, T2 … Tn are the allowed time intervals (see
Table 4-1) for the mentioned segments of exposure. Unlike a sound level meter,
a dosimeter computes automatically the exposure, D, and displays the accumu-
lated percentage of the allowed exposure.
Duration computed from where L = dB level, and rt = exchange
rate = 5 dB, in this example table.
*From the Federal Register, Vol. 46, No. 162, August 21, 1981.
B
2 exp (L-90) rt
D+C1 +C2 +—+Cn
T1 T2 Tn
Table 3-2. Permissable Noise Exposure Limits for Continuous Noise

15
3.3.2 Impact Noise
For compliance, exposure to impulsive or impact noise must not exceed 140 dB
A peak sound level.
3.4 Dosimeter
To accurately determine a dosage level using a sound level meter is a tedious
procedure, as the total length of exposure at each dB level must be weighted and
summed (accumulated). The dosimeter function of the 897 automatically and
continuously performs these mathematical manipulations while it is operating
and provides the dosage readout directly in percent of allowable exposure.
3.5 Dosimeter Equation
The dosimeter function is defined by ANSI S1.25 as:
Since the A/D converter is performing continuous integration, the computer must
only resolve:
Note that the result is expressed as a percentage.
The equivalent sound level during the sample time, T, over which a percentage
criterion exposure (dose) is measured, is:
D = percentage criterion exposure;
Tc = criterion sound duration, defined as 8 hours;
T = actual exposure duration in hours;
L = slow, A-weighted sound level;
Lc = criterion sound level;
Lt = threshold level
rt = exchange rate: the change in sound level corresponding to a doubling or
halving of the exposure duration.
User selectable items:
Lt = 50 to 99 db;
Lc = 70, 80, 84, 85 or 90 dB;
rt = 3, 4 or 5 dB.
Upper level of allowable equivalent (Leq) sound level exposure: 115 or 130 dB.
Dose (D) =100
Tc 10
冕0
T
L-Lc
qdt (when L> Lt)
Where q=rt
log 2
Thus:
D=100
Tc 2
冕0
T
L-Lc
rt dt
D=100
Tc
L-Lc
rt
兺
2
Leq =Lc + qlog DTc
100 T

16
3.6 Sound Fields
3.6.1 Free Field
This field contains no reflecting objects. Ideally it is a point sound source located
in free space; however, it can be considered to exist whenever the sound level
being measured is caused mainly by the sound waves coming directly from the
sound source. This can occur even if there are reflecting objects.
3.6.2 Reverberant Field
This field is more common and exists whenever the sound level being measured
contains a significant amount of direct sound waves and a relatively small amount
of reflected sound waves.
3.7 Microphone Orientation
3.7.1 Area Monitor in a Free Field
When the Instrument is used as a fixed monitor in a free field or in a semi-
reverberant field, the axis of the microphone should be oriented at approximately
70° with incident sound waves. Furthermore, the microphone should ideally be
placed as far from reflecting sound surfaces as possible. (See below.)
3.7.2 Fixed Position Monitor in a Reverberant Field
When monitoring in a reverberant field, orientation of the microphone is not criti-
cal.
3.7.3 Use of Dosimeter as a Personal Monitor
For a practical and efficient application, clip the microphone to the shirt, on the
shoulder just below the ear, with the microphone diaphragm facing upward.
NOTE: The user of the Instrument disturbs the sound field near the microphone at
the upper limit of frequencies. For many practical situations, the measurement
error is relatively small, typically 1 to 3 dB higher than would occur with a fixed
monitor position. Since the fixed monitor cannot easily follow the motion of a
mobile individual, the personal dosimeter is the most accurate, practical means
of measuring individual noise dosage.
SOUND
SOURCE SOUND
WAVE
70˚
AXIS OF
MICROPHONE
AXIS OFINCOMING
SOUND WAVE
MICROPHONE
Figure 3-2. Microphone Orientation

17
3.8 Windscreen
NOTE: When the 897 is exposed to a dusty or windy environment, the windscreen
should be used to protect the microphone diaphragm from damage, and to as-
sure a correct reading.
The windscreen will reduce the effects of wind noise by approximately 20 dB
without seriously affecting the frequency response of the microphone.
Grease and dirt on the windscreen may affect the accuracy of sound measure-
ments. Under severe conditions the windscreen should be cleaned often. To
clean, wash with a mild detergent, thoroughly rinse and dry before placing over
the microphone.
4. OPERATION
This section provides the instructions required for the operation of the 897.
4.1 Safety Precautions
Read Section 3 before performing dosage measurements. Section 3 contains
important information pertaining to sound and noise measurement terminology,
standards, operating techniques and precautions.
4.2 Operating Items And Features
All front panel operating controls are described in Table 4-1 and shown in Figure
4-1. Top panel adjustments, controls and connectors are described in Table 4-2
and shown in Figure 4-2.
Table 4-1. Front Panel Operating Features
1. “OFF-RUN-HOLD” Control
Switch:
A3-position slide switch used to
activate the Instrument and
“hold” accumulated data.
“OFF”: Power is removed from
the Instrument and all accumu-
lated data is erased. When
switching from “RUN” to “OFF”,
there is a minimum three sec-
ond delay before the 897 actu-
ally goes off. This will aid in pre-
venting accidental loss of accu-
mulated data. During this three
second period, the display may
appear dim; this is normal op-
eration.
“RUN”: In “RUN” mode all data
relating to DOSE, Leq, INT (60
sec), MAX and PEAK is continu-
ously monitored, updated and
stored, except when in SPL
mode of operation. In the SPL
mode, all dosimeter functions
OFF RUN HOLD LOCK
SIMPSON ELECTRIC CO. ELGIN , IL 60120
897 DOSIMETER
SOUND MEASURING SYSTEM
SPL
"CAL"
INT
(60 sec)
DOSE
PEAK
Leq
MAX
TIME PRINT
TEST SETUP
12
3
4
5
6
7
8
9
LO BATT
SPLMAX
INT60s
% DOSE
dBA
Figure 4-1. Front Panel

18
are suspended and printouts will indicate “HOLD” during the time SPL is
selected.
“HOLD”: In “HOLD” mode all data is retained without any modification except
that the elapsed time clock is kept running. The display will alternately flash
between “HOLD” and the presently selected function.
2. Control Switch “LOCK”:
A spline head screw is used to “lock” the control switch. Locking the control
switch, together with the keyboard switch lockout feature, provides protec-
tion against unauthorized tampering with control settings. To activate the
keyboard lockout, slide the “OFF-RUN-HOLD” switch to “HOLD”, then select
the desired function and while still holding that function button down, slide
the “OFF-RUN-HOLD” switch to “RUN”.
NOTE: The display will indicate four dashes (- - - -) for approximately five
seconds. At this point, none of the touch switches will respond. The keyboard may
be reactivated by again sliding the “OFF-RUN-HOLD” switch to “HOLD”.
3. Readout Display:
Four-digit LCD display plus eight special functions/units.
4. SPL (CAL):
When selected, the Instrument functions as a sound level meter. It reads the
incoming sound pressure level on a real time basis, and displays the A-
weight dB reading.
NOTE: All dosimeter functions are suspended, and the printouts will indicate
“HOLD” during the time SPL is selected. The “SPL” mode is also used to calibrate
the Instrument when its microphone is inserted into the Model 887 Calibrator.
When the “SPL (CAL)” button is held down for three seconds until “CAL” is dis-
played, the reading will be retained in memory along with the time, date, and
position of the “RANGE” switch. The latest two such readings are always stored.
These saved readings are only viewable with the data output printout.
5. DOSE/PEAK:
Alternately displays the DOSE in percent or the number of 140 dB (or greater)
peaks that have been detected since entering “RUN”.
6. TIME:
Alternately selects an elapsed time display of “minutes:seconds” or
“hours:minutes” since the Dosimeter was first switched into “RUN” mode.
“Hours:minutes” is displayed with a flashing color indicator.
7. INT (60 sec):
Displays the sound pressure level integrated average over a 60 second time
period. The 60 second time period begins whenever the Dosimeter is switched
into “RUN” from either “OFF” or “HOLD”. It then updates continuously using
the latest 60 seconds of accumulated sound pressure levels. Additional de-
pressions of this button will sequentially display the latest settings of the
programmable options, namely: cirterion level, threshold level, exchange
rate, time weighted average upper limit, serial output format, unit ID, baud
rate and time clock. Notice that it is not possible to change the settings here,
only to observe them. Refer to paragraph 4.6 for programming procedures.
8. Leq/Max:
Alternately displays Leq, based on eight hours, in dB or the maximum sound
pressure level in dB since entering “RUN”.
9. Print:
Instrument prints out one of the two output formats available from the data
logger depending on which accessory cable is presently connected. This
switch only functions while the Dosimeter is in the “HOLD” mode. (See para-
graph 4.9 for further information.)

19
SPL
CAL
RANGE
50/100 80/130
EXTDC
DATA OUTPUT
23
41
4.3 Top Panel Operating Features
Table 4-2. Top Panel Operating Features
1. RANGE switch: A 2-position switch that selects the operating range for
sound level measurements. The available ranges are 50
to 100 dB and 80 to 130 dB. The data logger records the
position of the switch and the time of any changes in the
position.
2. SPL (CAL)
adjust: Used with a calibrator to set the correct level.
3. EXT DC: Used with the supplied battery charger to recharge the
internal nickel-cadmium batteries. The Dosimeter may be
operated while connected to the charger.
4. DATA OUTPUT
CONNECTOR: Use with either parallel or RS-232 Serial accessory cable
to obtain data.
4.4 Battery Charging
The 897 is designed to be used with the Simpson Battery Charger(part no. 6-
115095) which is insulated well enough to permit use of the 897 while being
charged. This charger has a rated input of 108V AC to 264V AC at 50/60 Hz. Use
of any other charger may be hazardous to the operator or the 897.
The self-contained, rechargeable nickel cadmium battery pack should be charged
before operating the Instrument for the first time, or when the Low Battery Indica-
tor “LOBATT” is displayed, or before extended use where a power source is not
available.
The Instrument may be operated with the battery charger connected and thereby
maintaining its charge, however, cycling of the charge is “healthy” for Ni-Cad
batteries and extends their life. Do not attempt to keep them fully charged all the
time.
Figure 4-2. Top Panel

20
The approximate required time to fully charge the battery pack, in hours, is lin-
early proportional to the operating time of the dosimeter. See graph (Figure 4-3)
below.
The Instrument will operate from the battery for approximately 40 hours between
charges in the “RUN” position or approximately 60 hours between charges in the
“HOLD” position, however, this time will vary according to use.
4.5 Preliminary Checks
Set the “OFF-RUN-HOLD” switch to the “RUN” position. When the unit is first
turned on, a display segment test is performed. Next, the 897 will display in
sequence given:
Lc nn (Criterion Level)
th nn (Threshold Level)
rt n (Exchange Rate)
SPL Display
Example:
4.5.1 Underrange Display
The display will indicate “ur” if the SPL is underrange; i.e., under 50 on the 50 to
100 dBrange or under 80 on the 80 to 130 dBrange.
4.5.2 Overrange Display
The display will indicate “- - - -” if the SPL is overrange, i.e., over 100 on the 50 to
100 dBrange, or over 130 on the 80 to 130 dBrange.
4.5.3 Diagnostic Memory Test
The Instrument automatically performs a self diagnostic-memory test when turned
on. However, the operator may access and display this self-test routine via the
“TEST” switch. The self-test contains a complete memory diagnostic, a display
test routine, and a continuous real-time clock display. These three tests are en-
abled by pressing the “TEST” switch down and sliding the “OFF-RUN-HOLD”
switch to “RUN”. The display will first show “t 1.” If that passes, it will automatically
proceed to “t 2” and “t 3.” Each of these tests (t) are verifying different portions of
the internal memories. If any of these fail, the display will change to “Err” with the
16
10
2
015 40
OPERATING TIME
(HOURS)
CHARGE
TIME
(HOURS)
Figure 4-3