16
[STAND] key. the STAND annunciator will be on and the
SLOPE annunciator will start to flash, indicating that the
standardization at buffer 7.00 (or 6.86) is completed and the
instrument is ready to be sloped at a second buffer. The
instrument will display the buffer value corresponding to
the temperature of the buffer 7.00 (or 6.86) set in 4.2 (refer to
table 1). If the reading still drifts, repeat 4.3 until a stable
reading is obtained.
If "
Er 1
" is displayed, check that the correct buffer is used
and that the electrode offset is greater than - 1.5 pH and less
than +1.5 pH. Replace the buffer and/or the pH electrode.
Press the [CLEAR] key and repeat from 4.1. "
Er 1
" may
appear if the [STAND] key is pressed before the electrode
and ATC/Temp probe settle to within ±1.5 pH of the buffer
value. Allow sufficient time for the electrode and
ATC/Temp probe to stabilize before taking any action.
4.4 Remove the pH electrode from buffer 7.00 (or 6.86), rinse
with
distilled water and immerse it in buffer 4.01 or 9.18 or 10.01.
Set the instrument to the temperature of the 2nd buffer as in
4.2. The displayed temperature must be greater than 60.
℃
4.5 Allow sufficient time for the pH electrode to stabilize. Press
the [SLOPE] key. the SLOPE annunciator wills stop flashing
and stay on. The instrument will display the value of the
second buffer corresponding to the temperature of the
second buffer as set in 4.4 (refer to table 1). If the reading
still drifts, repeat 4.5, until a stable reading is obtained. The
instrument will calculate and compensate for the pH
electrode slope deviation corresponding to the values of the
two calibration buffers. The instrument is dual point
calibrated and is now ready for measurements.
