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Electrode Connections
1. Remove BNC shorting cap.
2. Attach electrode with BNC
connector by sliding BNC
connector onto electrode input
(1), then push down and turn
clockwise to lock into position.
NOTE: If using a combination
electrode with a BNC
connector, the reference
electrode input (2) is
not used.
3. Attach ATC probe with DIN
connector by sliding the DIN connectors into the ATC probe input (3) until
firmly in place.
pH Measurement Overview
pH measurement is easy and accurate with the Orion 720Aplus. The
meter/electrode system is calibrated with one to five buffers which bracket your
sample pH.
For better accuracy, at least a two buffer calibration is recommended.
The autocalibration feature automatically recognizes 1.68, 4.01, 7.00, 10.01, and
12.46 buffers. For best results, an ATC probe is recommended to compensate for
temperature variation.
ISE Measurement Overview
Direct measurement using ion selective electrodes (ISE’s) is fast and convenient
with the Orion 720Aplus. The meter/electrode system is calibrated with one to
five standards of known concentration which bracket sample concentration.
Unknown sample concentration is then read directly from the display in units
used for calibration molarity, ppm, %, etc.
Rec. Gnd. ATC/DIN KF Input 1 Ref.1 Input 2 Ref. 2
3
1
2
BNC Shorting Cap
Quick Start Guide
Orion 720Aplus pH/ISE Meter
All meter functions are described in detail in the accompanying instruction
manual. For calibration and measurement only a few steps are required.
Step-by-step instructions are given in this guide.
Meter Overview
1. Results and current mode are displayed in the large main field.
2. Channel, ready, and step-by-step prompts are displayed on the lower
prompt display.
3. The keys on the keypad have multiple functions. Their main function is to
enter numeric values. They also have primary functions. These are labeled
in white and are accessed by pressing 1st then the function. Most keys also
have secondary functions. These are labeled in green, and can be accessed by
pressing 2nd, then the function.
4. If you want to escape the sequence you are in, or your are not sure of which
function you are in, pressing 1st and then measure will take you to the
MEASURE mode where you can start again.
Meter Connections
Power
1. Plug line adapter into an appropriate wall outlet.
2. Plug line adapter firmly into power input on rear panel of meter.
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Quick Start Guide
Orion 720Aplus pH/ISE Meter
Calibration of Ion-Selective Electrodes (ISE) with
Two Standards
1. Verify selected input is currently in use. If input 1 to be used, the prompt line
should indicate “1-”. If input not correct, press 2nd, then channel repeatedly
until selected input is displayed.
2. Select concentration mode by pressing mode until “CON” is displayed on
main display.
3. Place electrode(s) into first standard and stir moderately.
4. Press calibrate. The date and time of the last calibration is displayed.
5. Press 2 then yes to select 2 standard calibration.
6. When “READY ENTER VALUE” is displayed on prompt line, indicating
electrode is stable, enter value of standard and press yes. The standard value
is entered, stored and the meter display freezes for three seconds. The meter
automatically switches to standard 2.
7. Remove electrode(s) from first standard. Rinse with deionized water.
8. Place electrode(s) into second standard.
9. When “READY ENTER VALUE” is displayed on the prompt line, indicating
electrode is stable, enter value of standard and press yes.
10. The electrode slope is calculated and then actual value is displayed for five
seconds. Meter will then automatically proceeds to the MEASURE mode.
11. Remove electrode(s) from standard. Rinse with deionized water. Place
electrode(s) into sample. When “RDY” is displayed record sample results.
See the appropriate electrode instruction manual for preparation of sensing and
reference electrodes, required solutions (ionic strength adjusters, standards, etc.)
and other special requirements. For best results during calibration, always use the
most dilute standard first, and always use a fresh aliquot of standard.
pH Autocalibration with Two Buffers
1. Verify selected input is currently in use. If input 1 to be used, prompt line
should indicate “1-”. If input not correct, press 2nd, then channel repeatedly
until selected channel is displayed.
2. Select pH mode by pressing mode until “pH” displayed on main display.
3. Place electrode(s) into pH 7 buffer and stir moderately.
4. Press calibrate. The date and time of the last calibration is displayed.
5. Press 2 then yes to select two buffer calibration.
6. When “RDY” is displayed on prompt line, indicating electrode stability, press
yes. The buffer value is entered, stored and meter display freezes for three
seconds. The meter automatically switches to buffer 2.
7. Remove electrode(s) from first buffer. Rinse with deionized water.
8. Place electrode(s) into second buffer.
9. When “RDY” is displayed on prompt line, press yes.
10. The electrode slope is calculated and then actual value (in percent) is
displayed for five seconds. Meter will then automatically proceed to the
MEASURE mode.
11. Remove electrode(s) from buffer. Rinse with deionized water. Place
electrode(s) into sample. When “RDY” is displayed record the sample results.
233944-001 Rev.C
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