Thermo Orion 420Aplus User manual

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 connector into the
ATC probe input (3) until firmly in place.
pH Measurement Overview
pH measurement is easy and accurate with the Orion 420Aplus. The
meter/electrode system is calibrated with one to three buffers that bracket your
sample pH.
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Quick Start Guide Orion 420Aplus pH 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 are displayed in the large main field of the display.
2. Mode is indicated by ▼along the bottom of the display corresponding to the
legend below it.
3. Some of the keys on the keypad have multiple functions. Their primary
functions are labeled in white. For those with secondary functions, these
functions are labeled in green, and are accessed by pressing 2nd then the
function.
4. The parameters in the setup menu are preset to typical values and usually
do not require changing. Please see instruction manual if changing
parameters is necessary.
5. If you want to escape the sequence you are in, or you are not sure of which
function you are in, pressing 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.

Quick Start Guide Orion 420Aplus pH Meter
7. When “READY” is displayed beside the reading, indicating electrode
stability, the reading will flash. Press yes. The buffer value is stored and
meter display freezes for three seconds. (If the third buffer is prefered, repeat
step 5, 6, and 7. Slope will automatically display on meter. For two buffer
autocalibration, continue to next step.)
8. After the second buffer value has been entered, press measure. The electrode
slope will be displayed. SLP appears in the lower field while the actual
electrode slope, in percent, appears in the main field.
The meter automatically advances to the MEASURE mode. MEASURE is
displayed above the main field.
9. Remove electrode(s) from buffer. Rinse with deionized water. Place
electrode(s) into sample. When “READY” is displayed beside the reading,
record the sample results.
For better accuracy, at least a two buffer calibration is recommended.
The autocalibration feature automatically recognizes 4.01, 7.00, and 10.01 buffers.
For best results, an ATC probe is recommended to compensate for temperature
variation.
pH Autocalibration with Two Buffers
NOTE: Do not scroll values when using autocalibration.
1. With power on, select the pH mode, by pressing mode until ▼, the mode
indicator, is aligned with the pH legend along bottom of display.
2. Place electrode(s) into pH 7 buffer and stir moderately.
3. Press 2nd then cal to begin calibration. The date and time of the last
calibration will be displayed.
4. When “READY” is displayed beside the reading, indicating electrode
stability, the reading will flash. Press yes. The buffer value is stored and
meter display freezes for three seconds. The meter automatically switches to
buffer two, indicated by the “P2” on the display.
5. Remove electrode(s) from first buffer. Rinse with deionized water.
6. Place electrode(s) into second buffer and stir moderately.
233940-001 Rev. C