Aquametrix 2200P pH Analyzer/Controller User Manual - Manual (Page 15)

Model 2200P Page 13
4.13 Watchdog Timer and Self Diagnostics
4.13.1 The 2200P continuously monitors the condition of all key components of the
measuring system to ensure that the measurements are reliable. Invalid entries and
memory loss are indicated on the panel. See Section 8.0.
4.14 Cycle Feature
4.14.1 With this feature the output of Relay A and/or Relay B can be cycled. The ON time
and the OFF time are independently adjustable. This feature can help eliminate the
problem of overshooting. Saving expensive chemicals.
5.0
START-UP AND OPERATION
5.1 Password
5.1.1
To enter the menu press MENU and the PASSWORD LED will illuminate. If the dip
switch has disabled the password feature, TEST will be the first menu item
illuminated when the MENU button is pressed. With each press of MENU button
you will step through the menu. When the last item, ALARM LOW is reached the
menu wraps around to TEST. If you have enabled PASSWORD by placing DIP
Switch No. 2 of Bank S1 in the off position you must enter the password “6” when
PASSWORD is indicated, if you wish to change any stored value. If the password
is enabled and you do not enter the correct password. All the items in the menu will
be read only.
5.2 Calibration
5.2.1 All pH systems must be calibrated when first installed, and re-calibrated each time
that a new probe is installed. Calibration should be performed regularly to ensure
optimal performance. The frequency of calibration can only be found through the
operator’s experience, as all processes will vary.
The 2200P can be calibrated in “manual calibration mode” or in “auto calibration
mode”. In the manual calibration mode the user must use the arrow keys to make
the display read the pH of the buffer solution. In the auto calibration mode, the
controller will recognize the standard pH buffers of 4, 7 and 10pH. In auto
calibration mode there is no need to use the arrow keys to correct the display.
Manual calibration is explained in this section, Auto calibration is explained in
Sec.5.3.
5.2.2 To calibrate the instrument in “manual calibration mode” you will need:
• two buffer solutions of known pH
• a beaker of clean water
Commonly used buffers have values of 4 pH, 7pH, and 10 pH. All are available
from Water Analytics. 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. You may also use
any other solutions of known pH value. When calibrating use the buffer closest to