KROHNE OPTISENS PAS 2000 EN - Manual (Page 27)

SERVICE
6
27
OPTISENS PAS 2000
www.krohne.com 11/2008 • MA PAS 2000 R04 en
Service
6.1 Maintenance
PAS 2000 sensors are easy to maintain. An electrode maintenance schedule should be kept,
listing when it is removed and cleaned. When this is done, the electrode should be checked
against a known buffer solution. If the control value does not match, a re-calibration should be
made.
Regularly check that the sensor does not get damp or wet inside during cleaning and other
activities. Also check that the electrode is correctly mounted in its holder to avoid leaking.
6.1.1 Broken electrode
Lightning or static discharges during thunder storms may cause damage to the electrode, and
could also damage the signal amplifier. The electrode is the most exposed point since it is in
direct contact with the water and, consequently, the ground connection for a discharge.
Physical damage to the electrode usually makes measuring impossible. Make sure that neither
electrode nor cable is damaged.
6.1.2 Error messages
CAUTION!
Use distilled water for cleaning, otherwise the calibration and in worst case the total life time of
the electrode might be compromised.
Display text Explanation Cause Solution
Unkown buffer The smart calibration
does not recognize the
current buffer from the
signal of the electrode. Unknown buffers have
been used. Use standard buffers
4.00, 7.00 and 10.00.
Broken sensor,
damaged electronic
components or bad
cable connection. Check or reseat cable
connection. Inspect
electrode and exchange
it if damaged.
Same buffer During calibration the
PAS 2000 pH does not
perceive a difference of
buffers. Same buffers have been
used. Make sure that you use
two different buffers
during calibration.
The electrode or the
electronic components
in the sensor may be
broken. Inspect electrode and
exchange it if damaged.
.book Page 27 Friday, November 28, 2008 2:32 PM