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