15
values of the two calibration buffers. The instrument is dual
point calibrated and is now ready for measurements.
After two point calibration, pressing and holding the
[MEA./EFF.] key for about 5 seconds will display the new
electrode efficiency.
If "
Er 2
" is displayed, check that the correct buffer is used
and that the slope of the electrode is not off by more than
30% from the theoretical slope. Only buffers 4.01, 9.18 or
10.01 may be used for slope calibration. Replace the buffer
and/or the pH electrode. Press the [CLEAR] key and repeat
from 1.1. "
Er 2
" may appear if the [SLOPE] key is pressed
before the electrode and the ATC/Temp probe settle to
within 30% of the buffer value. Allow sufficient time for the
electrode and ATC/Temp probe to stabilize before taking
any action
If "
Er 3
" is displayed, the buffer temperature is out of the 0
to 60
℃
rang. Bring the buffer temperature within the range
and repeat 1.2 It is not necessary to press the [CLEAR] key.
4. Calibration with manual temperature compensation in the pH
mode.
4.1 Connect the pH electrode to the top of the instrument (refer
to figure 1). The MAN annunciator will be on. Press the
[MODE] key for the LCD to indicate pH and for the AUTO
annunciator to be on.
4.2 Rinse the pH electrode in distilled water and immerse in
buffer 7.00 (or 6.86). Set the instrument to display the
temperature of the buffer by pressing the [
∆
] and [
∇
]
keys. The displayed temperature must be less than 60
℃
.
4.3 Allow sufficient time for the electrode to stabilize. Press the
