Campbell Scientific CS526 ISFET pH Probe - Manual (Page 18)

CS526 ISFET pH Probe
Problem:
Output signal is at its maximum value.
Possible reasons:
o Probe is not in fluid.
o Chip is polluted.
o Diaphragm is polluted.
o Chip is scratched.
Suggestions:
o Put probe in fluid.
o Clean probe (Section 9.1, Cleaning).
o Probe cannot be fixed if chip is scratched.
Problem:
Probe response is very slow.
Possible reason:
o Diaphragm is chipped or polluted.
Suggestion:
o Clean probe (Section 9.1, Cleaning).
Problem:
Probe signal is drifting.
Possible reasons:
o Diaphragm can be dried out.
o Chip is scratched.
Suggestions:
o Soak probe for 10 minutes in saturated KCl solution (pn 16349).
o Probe cannot be fixed if chip is scratched.
9. Maintenance
The CS526 needs to be periodically cleaned and calibrated
to ensure accurate readings and proper operation.
The CS526 has no user-serviceable parts.
9.1 Cleaning
Proper maintenance of a probe is important. If the probe is not properly and
regularly cleaned, the probe can malfunction due to a contaminated diaphragm
or ISFET chip. Contamination on/or blockage of the sensor and reference
electrode diaphragm surface is the most likely cause for probe failure.
Probe wear is another cause for probe failure. Probe wear is often, but not
necessarily, preceded by a period of declining calibration slope values. Probe
wear is dependent on how the probe is used and stored (see Section 9.2,
Storage). Worn probes need to be replaced.
9.1.1 When to Clean
Often the probe should be cleaned daily, but the appropriate cleaning frequency
is dependent on the type of sample being measured.
CAUTION
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