user manual

Input Calibration
January 2009 UDA2182 Universal Dual Analyzer Product Manual 139
8.4 Recommendations for Successful Measurement and Calibration
Selection and care of electrode system or cell essential
Successful measurements and calibration depend upon selection and care of the electrode
system or cells. Always prepare electrodes or cells and their mountings in accordance
with the instructions supplied with them, observing temperature, pressure and flow
limitations. Note the following recommendations:
pH/ORP Calibration
•
Rinse electrodes thoroughly between buffer solutions.
• Always use HOLD, or otherwise deactivate control or alarm circuits before removing
electrodes from the process.
• Standardize with a buffer solution, which is at about the same temperature and pH as
the sample solution.
• Inspect and, if necessary, clean and/or rejuvenate the electrode system periodically
according to experience and conditions.
Conductivity Calibration
• For most accurate temperature measurement and compensation, insulate the outer body
of the cell to minimize the effect of ambient conditions on process temperature
measurement.
• Rinse the cells thoroughly with de-ionized water before immersing in a reference
solution.
• Always deactivate control or alarm circuits before removing cells from the process.
• Do calibration trim with a reference solution, which is at about the same temperature
and conductivity as the process solution.
• Inspect and, if necessary, clean the cells periodically according to experience and
conditions.
ATTENTION
For successful measurement in pure water applications where plastic piping is used, you may
have to provide an earth ground for the cell. Run a wire from the black electrode terminal of the
cell to one of the earth ground screws.