YOKOGAWA DO30G, User Manual

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<4. Maintenance>
4-1
IM 12J5B3-01E
4. Maintenance
This section describes the inspection and maintenance procedure applicable to just the dissolved
oxygen sensor alone. For comprehensive inspection and tuning of the measuring system, such
as calibration, see the FLXA402 4-Wire Converter instruction manual (IM 12A01F05-01EN), the
DO402G Dissolved Oxygen Converter instruction manual (IM 12J05D02-01E), the FLXA202/
FLXA21, DO202 2-wire Transmitter instruction manual (IM 12J05C01-01E/IM 12A01A02-01E) .
4.1 Routine Inspection
4.1.1 Inspecting the Permeable Membrane (Degree of
Contamination)
An inspection (visual) of the permeable membrane must be made whenever the sensor is cali -
brated. Any dirt on the membrane will adversely affect your measurements. If the dirt is spread
over the membrane, dip the membrane into clean water and gently wipe the dirt off with a soft
cloth or lint-free paper. If the dirt will not come off easily, apply a neutral detergent to the mem -
brane so it will be easier to remove the dirt. Clean the membrane with clean water. Finally, make
sure the permeable-membrane assembly locknut is not loose.
CAUTION
Exercise care to avoid wrinkling or damaging the permeable membrane during inspection.
Wrinkling and other damage prevent normal membrane operation.
4.1.2 Checking of Membrane Assembly Locknut
At every calibration, check that the membrane assembly locknut is not loose. If it is, retighten it.
In addition, if a phenomenon which is considered to be due to a change in the electrolyte qual-
ity (e.g., showing extremely low measured values) is observed after the locknut is retightened,
replace the electrolyte according to the directions in Subsection 4.2.1.
6th Edition : Nov.20,2018-00
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