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3

pH Calibration Using Automatically Recognized Buffers

Note:

Use a 6.86 or

7.0 pH buffer for the
mid-range buffer.
Choose the pH setup
option in Table 1.

1.

Prepare two or three pH buffers according to the electrode
instruction manual. Choose from 1.68, 4.01, 7.00 (or 6.86), 10.01,
and 12.45 pH buffers.

2.

Turn the instrument on. From the pH reading mode, press

CAL

.

CAL

and flashing

?

will appear in the upper display area, along

with

Standard

and

1

.

3.

Place the pH electrode into one of the buffers.

4.

Press

READ

. The instrument will automatically recognize the

calibration buffer value. The temperature and pH values will be
updated until a stable reading is reached.

Note:

The pH values for the buffers are given for 25 °C. If the calibration buffer

temperature is not 25 °C, the pH values displayed for the buffers will reflect
the correct pH value for the calibration buffer temperature.

Note:

If the meter is measuring in pH mode, it automatically moves to the next

calibration step when stabilization is reached (indicated by three beeps). If
measuring in mV mode, the three beeps will still sound when the
stabilization occurs, but

ENTER

must be pressed to accept the reading. This

lets the operator control the acceptance point of the buffer.

5.

When the reading has stabilized or been accepted, the standard
number will change to

2

.

6.

Remove the probe from the first buffer and rinse with deionized
water. Place the probe into the second buffer.

7.

Press

READ

. The temperature and pH values will be updated until a

stable reading is reached.

8.

When the reading has stabilized or been accepted, the standard
number will change to

3

. (To accept this calibration after two

points, press

EXIT

. Press

ENTER

to accept the calibration or

EXIT

to

cancel the calibration without saving it.)

9.

Remove the probe from the second buffer and rinse with deionized
water. Place the probe in the third buffer.

10.

Press

READ

. The temperature and pH values will be updated until a

stable reading is reached.

11.

When the reading has stabilized or been accepted, the slope value
and the

Store

and

?

icons will appear.

12.

To save the calibration and return to the reading mode, press

ENTER

. To exit the calibration without saving it and return to the

reading mode, press

EXIT

.

Содержание SensION156

Страница 1: ...54650 23 and Multiparameter Meters ...

Страница 2: ...esired option is selected press EXIT to return to the reading mode Setup 5 Display Lock From pH reading mode press SETUP Press the UP ARROW until the Setup number is 5 Press ENTER to toggle display lock off and on When the desired option is selected press exit to return to the reading mode Setup 6 Measurement Resolution From pH reading mode press SETUP Press the UP ARROW until the Setup number is ...

Страница 3: ... by three beeps If measuring in mV mode the three beeps will still sound when the stabilization occurs but ENTER must be pressed to accept the reading This lets the operator control the acceptance point of the buffer 5 When the reading has stabilized or been accepted the standard number will change to 2 6 Remove the probe from the first buffer and rinse with deionized water Place the probe into th...

Страница 4: ...onductivity reading mode press SETUP Press the UP ARROW until the Setup number is 7 Press ENTER Press the UP or DOWN ARROW keys to switch between linear and non linear correction functions To choose a non linear conversion scroll until a flashing NaCl appears then press ENTER To select a linear conversion scroll until the conversion coefficient appears Use the numeric keypad to set the value of th...

Страница 5: ... the most recent type of calibration 5 Look at the units field to see what kind of calibration is active Scroll to the preferred units using the UP or DOWN ARROWS 6 Use the number keys to change the numeric value if desired It is not necessary to fill up the numeric entry screen before moving on To clear the numeric display press CE 7 When the value and units are correct press ENTER to calibrate o...

Страница 6: ...press EXIT to return to the reading mode Setup 7 Salinity Factor Determine sample salinity The units for salinity are parts per thousand 0 00 From dissolved oxygen reading mode press SETUP Press the UP ARROW until the Setup number is 7 Press ENTER Use the number keys to enter a salinity factor ranging from 0 to 42 Press ENTER to accept the value or EXIT to leave the value unchanged When the desire...

Страница 7: ...n the chamber to reach a steady state Note Gently squeezing the lower chamber a couple of times to force water saturated air into the probe chamber will speed up stabilization Note Keep the DO probe at a uniform temperature When holding the probe do not touch the metallic button on the side of the probe The button is a thermistor that senses temperature An inaccurate calibration will result if the...

Страница 8: ...rily disconnect the probe If the CAL and icons flash after calibrating the DO probe the probe is not polarized Connect the pH electrode to the black connector and the DO or conductivity electrodes to the blue connector If the meter is not in reading mode it may take a few key presses to turn the meter off If the readings do not change when you move an electrode to a new sample the meter probably h...

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