Crison MultiMeter 44 Manual Del Usuario página 27

One-point calibration
This type of calibration is acceptable when measuring pH values similar to those of the
buffer solution. It corrects the asymmetry potential of the electrode.
Two-point calibration
This is the most common calibration. It is recommended to start with pH 7 as first buffer.
pH 4 or pH 9 buffers can be used as a second buffer, depending on the measured zone
(acid or alkaline).
The two-point calibration compensates the asymmetry potential and the electrode's
sensitivity (slope).
Three-point calibration
This type of calibration is recommended when measurements are made across the whole
pH scale. As a first point pH 7 is recommended. For the second and third points, two of the
remaining values must be chosen.
The three-point calibration pH 4.00, 7.01 and 9.21 (at 25ºC) compensates the asymmetry
potential and electrode's sensitivity in the acid and alkaline zone.
Calibration procedure
This procedure is for general use with liquid calibration solutions. Refer to the documents
that are included with each probe for additional information.
1. Pour the buffers or calibration solutions into labeled calibration beakers.
2. From the main menu select
3. Select the channel to calibrate and confirm.
4. Select
CALIBRATE WITH BUFFERS
Note: During calibration with buffers, the relays assigned to the corresponding channel stay
deactivated. The 4-20 mA outputs (register) are in Hold (21 mA or last value).
* Channel 2 and 3 activated. This message appears when Individual Hold (sensors installed in
different places) is programmed.
The configuration of set Hold means relays deactivation of all channels during calibration with
standards of any of the sensors.
5. Put the probe into the first calibration beaker.
Note: For practical reasons in calibration is recommended to select the temperature manually
despite ATC is connected (Pt 1000).
6. Press to start and measure the first calibration solution.
OK
The next calibration solution is shown.
7. Press to end calibration or
ESC
8. Rinse the probe with deionized water and put the probe into the second calibration
beaker. Be sure that there are no air bubbles in the membrane.
9. Press to start and measure the second calibration solution.
OK
The next calibration solution is shown.
10. Press to end calibration or
ESC
11. Rinse the probe with deionized water and put the probe into the third calibration
beaker. Be sure that there are no air bubbles in the membrane.
12. Press to start and measure the third calibration solution.
OK
The instrument will display the calibration results and then returns to the main menu.
Confirm.
CALIBRATE.
and confirm.

to proceed with the next calibration point.
OK
to proceed with the next calibration point.
OK
Operation

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