Triplett SLM400 User manual

User Manual
SLM400
Digital Sound Level Meter
Introduction
Congratulations on your purchase of the SLM400 Digital Sound Level Meter.
This device is shipped fully tested and calibrated and, with proper use, will
provide years of reliable service.

Safety
Read the following safety information carefully before attempting to
operate or service the meter. Use the meter only as specified in this
manual; otherwise, the protection provided by the meter may be
impaired.
Environmental Conditions
Altitude up to 2000 meters
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Relative Humidity: 90% max.
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Operating Temperature: 0 to 40oC (32 to 104oF)
Maintenance and Cleaning
Repair or servicing not covered in this manual should only be
performed by qualified personnel.
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Periodically wipe the case with a dry cloth. Do not use abrasives or
solvents.
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Meter Description
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1. Microphone
2. 4-digit LCD Display
3. ON-OFF button
4. LCD Backlight button
5. Frequency weighting selection button
6. Response time selection button
7. Range selector button
1. Max Hold / Data Hold selector button
2. Battery compartment on rear
10. Calibration pots in battery compartment
11. Windscreen
Measurement Considerations
1. Wind blowing across the microphone increases the noise
measurement. Use the supplied windscreen to cover the
microphone when applicable.
2. Calibrate the instrument before each use if possible. Especially if the
meter has not been used for a long period of time.
3. Do not store or operate the instrument in areas of high temperature or
humidity.
4. Keep meter and microphone dry.
5. Avoid severe vibration.
6. Remove the battery when the meter is to be stored for long periods of
time.
7. Min:sec or Hour: min Display

Operation
1. Power the meter by pressing the
power button. The meter will begin displaying sound level
readings. If the LCD does not switch on, check the 9V battery
located in the rear battery compartment.
1. Hold the meter in hand facing the microphone toward the source of the
sound to be measured.
2. View the measurement on the meter’s LCD. An indication of OVER means that
the measurement is out of range. Toggle the ‘Hi’ (65 to 130dB) and ‘Lo’ (35 to
100dB) measurement ranges using the HI/LO button. For measurements in the
65 to 100dB region either range can be used.
‘A’ and ‘C’ Frequency Weighting
Use the ‘A/C’ button to select ‘A’ or ‘C’ frequency weighting. With ‘A’
weighting selected, the frequency response of the meter is similar to the
response of the human ear. ‘A’ weighting is commonly used for
environmental or hearing conservation programs such as OSHA
regulatory testing and noise ordinance law enforcement. ‘C’ weighting is
a much flatter response and is suitable for the sound level analysis of
machines, engines, etc.
Most noise measurements are performed using 'A' Weighting
and SLOW Response. ‘FAST’ and ‘SLOW’ Response Time
Use the ‘F/C’ button to select FAST (125 ms) or SLOW (1 second)
response time. Select FAST to capture noise peaks and noises that occur
very quickly. Select the SLOW response to monitor a sound source that
has a consistent noise level or to average quickly changing levels.
Select Slow response for most applications.

‘Hi’ and ‘Lo’ Range Selections
Use the ‘Hi/Lo’ button to select the appropriate range. If the measurement is
in the range of 35 to 100 dB, use the ‘Lo’ range. If the measurement is
between 65 and 130dB, use the ‘Hi’ range. For measurements between 65
and 100dB, either range can be used. If the display flashes the OVER icon,
press the range button to toggle the range.
MAX HOLD
In this mode, the meter only updates the LCD when a higher reading than
the one presently on the display is detected. Select MAX HOLD by
momentarily pressing the MAX HOLD button. The meter displays the MAX
icon when in the MAX HOLD mode. Press the MAX HOLD button again to
exit this mode (the MAX indicator will switch off).
DATA HOLD
To freeze a displayed reading, press and hold the MAX HOLD button until
the MAX and HOLD display icons appear. To release the display and
return to the normal operating mode, press and hold the MAX HOLD
button until the MAX and HOLD icons switch off.
Backlight button
The LCD is equipped with backlighting for easier viewing, especially in dimly
lit areas. Press the backlight button to turn the backlight on. Press again to
turn the backlight off. The backlight does not have an automatic power down
function; judicious use will conserve battery life.

Calibration
To calibrate the SLM400 an external calibrator that can provide a 94.0dB signal
at 1 kHz is required in addition to a small screw-driver.
1. Open the battery compartment and locate the two calibration
potentiometers behind the 9V battery (see
diagram)
1. Put the meter in the ‘C’ weighting mode
2. Put the meter in the ‘FAST’ response mode
3. Place the SLM400 microphone into the calibrator.
Set the calibrator to output a 1kHz sine wave @
94dB
4. Put the meter in the LOW range
5. Adjust the ‘C (Lo)’ potentiometer for a display of
94.0 dB
6. Put the meter in the HIGH range
7. Adjust the ‘C (HI)’ potentiometer for a display of
94.0 dB
Battery Replacement
When the low battery icon BAT appears on the LCD replace the 9V
battery as soon as possible. The battery compartment cover is located on
the rear of the meter. Remove the Phillips screw to loosen the cover.
Slide the battery compartment cover off, change the battery, and replace
the compartment cover.
You, as the end user, are legally bound (Battery ordinance) to
return all used batteries and accumulators; disposal in the
household garbage is prohibited!
You can hand over your used batteries / accumulators at
collection points in your community or wherever batteries /
accumulators are sold

Specifications
Display
4-digit (4000 count) backlit LCD
Display update rate
0.5 seconds
Microphone
0.5” Electret condensor
Measurement Bandwidth
31.5Hz to 8KHz
Dynamic range
65dB
Measurement Range
35 to 130dB (Low: 35 to 100; High: 65 to
130dB)
Frequency weighting
‘A’ and ‘C’ (selectable)
Accuracy / Resolution
± 1.5dB (under reference conditions) / 0.1dB
Standards
Meets Type 2 ANSI S1.4-1983, IEC 60651,
EN60651
Maximum Hold decay
time
<1dB / 3min
Response time
Fast: 125 milliseconds / Slow: 1 second
Calibration source
required
1KHz sine wave @ 94dB
Power
9V Battery
Battery life
50 hours (typical); low battery indicator alerts
user
Automatic power off
After approx. 15 minutes of inactivity
Operating temperature
0 to 40oC (32 to 104oF)
Operating humidity
10 to 90% RH
Storage temperature
-10 to 60oC (14 to 140oF)
Storage humidity
10 to 75% RH

Dimensions/weight
240 x 68 x 25mm (9.45 x 2.68 x 1”) /210g
(6.75oz)
Warranty Information
Triplett / Jewell Instruments extends the following warranty to the original purchaser of
these goods for use. Triplett warrants to the original purchaser for use that the products sold
by it will be free from defects in workmanship and material for a period of (1) one year from
the date of purchase. This warranty does not apply to any of our products which have been
repaired or altered by unauthorized persons in any way or purchased from unauthorized
distributors so as, in our sole judgment, to injure their stability or reliability, or which have
been subject to misuse, abuse, misapplication, negligence, accident or which have had the
serial numbers altered, defaced, or removed. Accessories, including batteries are not
covered by this warranty Copyright ©2020 Triplett