Extech SDL100 Operating Manual

User's Guide

pH/ORP Meter

SD Card real-time Datalogger

Model SDL100

Introduction

Congratulations on your purchase of the Extech SDL100 pH/ORP Meter, an SD Logger Series
meter. This meter displays and stores pH (from 0 to 14.00pH) and ORP (±1999mV) readings. A
temperature probe (supplied) can be inserted to the meter to provide automatic temperature
compensation. Logged data readings are stored on an SD card for transfer to a PC. In addition, an
RS232 port allows data streaming 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. pH/ORP Sensor input BNC jack

2. Temperature probe input jack

3. pH/ORP Measurement reading on LCD Display

4. Temperature reading on LCD Display

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 key

14. Up arrow ▲ / CAL key

15. Power ON-OFF

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

• Press and hold the power button

• Press and hold the power button for 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
(refer to the battery replacement section later in this guide) or, in the case of the AC adaptor,
check that the adaptor is connected correctly to the meter and to an AC source (refer to the AC
Power Adaptor section later in this guide).

for at least 1.5 seconds to power ON the meter.

pH/ORP mV Measurements

Selecting pH or ORP modes of operation

Press and hold the FUNCTION button for at least 1.5 seconds; the display will begin to toggle
between pH and ORP modes. Release the FUNCTION button when the desired mode is displayed.

pH Measurement Range

pH measurements are displayed in the range of 0.00 to 14.00 in the upper, larger digit display area
of the meter’s LCD. Measurements made outside of this range will yield dashes (- - -) on the meter’s
LCD. The Temperature value is shown below the pH reading on the LCD. Refer to the
Measurement section for further information.

ORP mV Measurement Range

Ion-selective ORP (Oxidation Reduction Potential) measurements are displayed in the range of
±1999 mV (millivolts) in the upper, larger digit display area of the meter’s LCD. Measurements
outside of this range will yield dashes (- - -) on the meter’s LCD.

Connecting the pH or ORP Electrode

The measurement electrode connects to the BNC socket on the top left of the meter. If a pH
electrode is being connected to the meter for the first time, please perform a calibration as
described in the Calibration section of this user guide.

Taking a pH or ORP Measurement

For pH measurements only, determine whether Manual or Automatic Temperature Compensation
will be used and then set up as required.

Immerse the pH or ORP electrode into the solution under test and gently agitate the solution with
the probe. When the meter’s display has stabilized, note the reading (stabilization may require
several seconds up to several minutes, depending on the solution).

When measurements have been completed, be sure to store the pH electrode in its protective cap
with a pH4 moistened sponge.

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Manual / Automatic Temperature Compensation (for pH measurements only)

Ph measurements are most accurate when the temperature of the solution under test is known and
a temperature compensation factor is applied to the measurement. This is achieved using Manual
or Automatic Temperature Compensation.

For Manual Temperature Compensation, the external temperature probe is not connected to the
meter and the temperature of the solution under test is manually entered in the Setup Mode. The
temperature entered is shown on the lower LCD line.

For Automatic Temperature Compensation, the external probe is connected to the meter and
inserted into the solution to be tested. The measured temperature of the solution is displayed on the
LCD.

Display Backlight

To turn the display backlight ON or OFF, press and hold the backlight
seconds.

Data Hold

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

Max-Min Reading Record and Recall

For a given measurement session, this meter can record the highest (MAX) and the lowest (MIN)
readings for later recall.

1. Press the MAX-MIN button momentarily to access this mode of operation (REC icon appears)
The meter is now recording the MAX and MIN readings.

2. Press the MAX-MIN button again to view the current MAX readings (MAX icon appears). The
readings on the display are now the highest readings encountered since the REC icon was
switched on (when the MAX-MIN button was first pressed).

3. Press the MAX-MIN button again to view the current MIN readings (MIN icon appears). The
readings on the display are now the lowest readings encountered since the REC icon was
switched on (when the MAX-MIN button was first pressed).

4. To exit the MAX-MIN mode, press and hold the MAX-MIN button for at least 1.5 seconds The
meter will beep, the REC-MAX-MIN icons will switch off, the MAX-MIN memory will clear, and
the meter will return to the normal operating mode.

button for at least 1.5

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