Metex 2200P pH Analyzer/Controller - Manual (Page 18)

Model 2200P Page 16
actual value, or the buffer solution is contaminated. If you are confident in your
buffer solution proceed by using the arrow keys to correct the display to read
the actual value of the buffer. Press ENTER. The display will flash until
ENTER is pressed again to confirm the value.
c) Rinse the probe in the clean water, and place it in the second buffer solution.
Repeat the same process as above to accept the second value.
d) The system is now calibrated. Press RUN to place the instrument on line or
use the MENU key to proceed to other menu items.
5.3 Auto Calibration
The AUTO CAL method of calibration is faster and even easier than the
CALIBRATION method but can only be used if the calibration solutions are two of
the three standard buffers, 4 pH, 7 pH, and 10 pH.
5.3.1 The 2200P will only recognize the buffers if the previous calibration is within 1 pH of
calibration. If sufficient time has been allowed to enable the probe to stabilize but
the display is blank, go back to CALIBRATION and proceed as in Section 5.2.0
To calibrate the instrument in “auto calibration mode” you will need:
• two buffer solutions of either 4 pH, 7 pH or 10 pH
• a beaker of clean water
If you are generally operating above 7 pH, it is recommended that buffers of 7 pH,
and 10 pH are used. If you are generally operating below 7 pH, it is recommended
that buffers of 7 pH, and 4 pH are used. If you are operating throughout the
0-14 pH range, use buffers of 4 pH and 10 pH. When calibrating use 7pH as your
first value, and the other as the second. If you are calibrating with 4 pH, and 10 pH,
use 4 pH as the first and 10 pH as the second.
a) Enter the menu by pressing MENU. Proceed by pressing MENU until the AUTO
CALIBRATION LED illuminates.
b) Remove the protective cap from the probe, rinse it in clean water, and place it
in the first buffer solution. The 2200P will automatically recognize the buffer and
display the value. The display may flash which indicates that the instrument is
receiving an unstable signal from the probe. When the display is steady, Press
ENTER. The display will flash until ENTER is pressed again to confirm the
value.
c) Rinse the probe in the clean water, and place it in the second buffer solution.
Again the instrument will recognize the buffer and will show the value on the
display. When the display is steady, Press ENTER. The display will flash until
ENTER is pressed again to confirm the value.
d) The system is now calibrated. Press RUN to place the instrument on line or
use the MENU button to proceed to other menu items