Two-Point Calibration With Auto Recognition Of Hach Buffers - Hach EC1000 Instruction Manual

2.3.1.1

Two-Point Calibration with Auto Recognition of Hach Buffers

Invalid Calibration Indication
During a calibration, if the offset is greater than ±300 mV, or if the slope is outside
the range of 44.2 to 89.5 mV, an invalid message is displayed and the calibration is
not accepted.
The buffers used in a two point calibration should bracket the pH range of the sample.
The following procedure uses the pH 4.01 (Cat. No. 22269-66) and pH 7.00
(Cat. No. 22270-66) Hach buffers supplied with the instrument, but a pH 10.00 Hach
buffer (Cat. No. 22271-66) can be used as one of the buffers. If buffers other than the ones
listed above are used, refer to Section 2.3.1.3 Calibration Procedure Variations.
1. Prepare a pH 4.01 Hach Buffer (Cat. No. 22269-66) and a pH 7.00 Hach Buffer
(Cat. No. 22270-66) by dissolving the contents of one powder pillow in 50 mL of
deionized water, and mix.
2. Remove the electrode from the sample solution and clean if needed (see Section 8.1
Electrode Maintenance).
3. Rinse the electrode with deionized water and then place the electrode in prepared pH
4.01 buffer (Cat. No. 22269-66).
4. Press to call up the main calibration menu.
CAL
The display shows:
5. Press . The display shows:
ENTER
6. Press . The display will show the current pH value.
ENTER
7. After the electrode stabilizes (refer to the stability indicator note), press
accept this calibration point.
8. Rinse the electrode with deionized water then place the electrode in prepared pH 7.00
buffer solution (Cat. No. 22270-66).
9. Press . The display shows:
ENTER
10. Press . The display will show the current pH value.
ENTER
11. After the electrode stabilizes (refer to the stability indicator note), press
accept this calibration point.
12. Press to return the meter to normal operations.
pH/mV
13. Rinse the electrode with deionized water and return it to the sample.
39
to
ENTER
to
ENTER