Extech SDL400 Operating Manual

User's Guide

Light Meter

SD Card real-time datalogger

Model SDL400

Introduction

Congratulations on your purchase of the Extech SDL400 Light Meter. This meter displays and
stores light meter readings in three ranges: 2,000 / 20,000 / 100,000 LUX or Foot candles from the
supplied domed light sensor. The meter automatically ranges light meter measurements and the
light sensor spectrum meets C.I.E.

This meter also displays and logs temperature readings from a connected Type J or Type K
thermocouple.

Logged data readings are stored on an SD card for transfer to a PC. This meter is shipped fully
tested and calibrated and, with proper use, will provide years of reliable service.

Safety

International Safety Symbols

This symbol, adjacent to another symbol or terminal, indicates the user must refer to the
manual for further information.

Meter Description

1. Temperature (thermocouple) input jack

2. Light Meter Sensor input plug

3. Measurement reading

4. Temperature units of measure

5. HOLD and Backlight

6. MAX-MIN key

7. SET and Clock

8. PC interface jack

9. Reset button

10. Power Adaptor jack

11. SD card slot

12. ENTER and LOG key

13. Down arrow ▼ / FUNCTION / ZERO key

14. Up arrow ▲ / UNIT / ZERO key

15. Power ON-OFF

16. Thermocouple type or Light measurement unit of measure

17. Light Sensor dome

Notes:

Items 8, 9, and 10 are located behind the snap-off compartment cover on meter’s right side.

Battery compartment, tilt stand, and tripod mount are located on the rear of the instrument

key

key

key

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Getting Started

Power ON-OFF

• Power the meter by pressing and holding the power button

• Press and hold the power button for at least 1.5 seconds to power OFF the meter.

• This meter is powered by six (6) 1.5VDC ‘AA’ batteries or by optional AC adaptor. If the meter

will not switch ON please check that fresh batteries are installed in the rear battery compartment
or, in the case of the AC adaptor, check that the adaptor is connected correctly to the meter and
to an AC source.

Display Backlight

To turn the display backlight ON or OFF, press and hold the backlight
seconds. The meter will beep when switching the backlight ON or OFF unless the beeper is
disabled as described in the Setup Mode section of this user guide.

Light Meter Sensor Connection

The supplied light sensor is connected to the meter via the DIN jack at the top right of the meter.
When taking measurements snap off the light sensor’s protective cover and then replace the cover
when finished.

Light Meter Units of Measure

The currently selected unit of measure is shown to the left of the light measurement reading on the
meter’s LCD. To change the unit of measure, press and hold the UNIT button until the desired unit
of measure appears and then release the UNIT button. The available light measurement units are
LUX and FOOT CANDLE (ft-cd).

Thermocouple Temperature Sensor Connection

A type K or J thermocouple temperature sensor can be connected via the sub-miniature
thermocouple jack at the top left of the meter. The display icon for the type of thermocouple
selected (J or K) is shown on the meter’s LCD to the left of the temperature measurement. To
change the type, use the Setup Mode.

Temperature Measurement Units of Measure

The currently selected unit of measure is shown below the temperature measurement reading on
the meter’s LCD. To change the unit of measure, press and hold the UNIT button until the desired
unit of measure appears and then release the UNIT button. The available temperature
measurement units are °C and °F.

for at least 1.5 seconds.

button for at least 1.5

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Measurements

Light Meter Measurements

1. Connect the light sensor to the top of the meter as previously described

2. Power the meter by holding the power button for at least 1.5 seconds

3. Select the Light Measurement mode by pressing and holding the FUNCTION button for at least

1.5 seconds (if necessary). The ‘LIgHt’ icon indicates the Light Meter mode

4. Select the desired unit of measure LUX or Foot candles by pressing and holding the UNIT
button for at least 1.5 seconds (if necessary)

5. Place the sensor on a surface, or hold in hand, with the domed area facing the light source
under test. The light sensor is dome shaped to accommodate light reaching it from various
angles.

6. Read the measurement on the meter’s LCD

7. This instrument measures light intensity (illuminance) in LUX or Foot candle measurement units

ZERO Adjustment (Light Measurement readings only)

To zero the light meter display, simply press and hold both arrow keys (▼ ▲) for at least 1.5
seconds. This is typically done with the protective sensor cover installed to ensure that a complete
absence of light displays a zero reading. This zero function can also be used as a relative, or offset,
function but remember to re-zero the meter with the protective cap on after such use.

Temperature Measurements

1. Connect the temperature sensor to the top of the meter as previously described

2. Power the meter by holding the power button for at least 1.5 seconds

3. Select the Temperature Measurement mode by pressing and holding the FUNCTION button for
at least 1.5 seconds (if necessary). The ‘tP’ icon indicates the temperature mode of operation

4. Select the desired Thermocouple Type (K or J) in the Setup Mode

5. Select the desired unit of measure (C or F) in the Setup Mode

6. Hold the thermocouple in the air in the area under test

7. Read the temperature measurement on the meter’s LCD

Important Safety Note on Thermocouple Ratings

The temperature range of this meter extends up to 1300°C (2372°F); however the range of
thermocouple probes vary greatly; be sure to select a probe rated for the expected temperature
measurement ranges.

Data Hold

To freeze a displayed reading on the LCD, momentarily press the HOLD button (the HOLD display
icon will appear above the held reading. To release the held reading press the HOLD button again.

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