User’s
Manual
Dissolved Oxygen Metering System
Model DO30G
Dissolved Oxygen Sensor
IM 12J5B3-01E
IM 12J5B3-01E
4th Edition
Introduction
The DO30G Dissolved Oxygen Sensor bases its principle of measurement on the galvanic-cell
method. The sensor is specically suited for continuous measurement of oxygen dissolved in
water.
Topics and information that need your special attention in handling the product are given in the
text of this manual along with cautionary notes, such as a warning or caution, depending on their
importance. Strictly observe these items from the standpoint of safety and prevention of equipment damage. For a notation, such as a warning also indicated on the product, there is an alert
mark in the manual.
1. Conrming the Specications
The standard specication DO30G dissolved oxygen sensor is used to build the dissolved oxy-
gen metering system.
The DO30G sensor cable has the prescribed length. The conguration of the crimp-on terminals
are either pin-type, M4 ring-type or fork-type.
Upon arrival of the purchased product, carefully unpack it and make sure the product is completely free from any damage that may have occurred during transport. Also check the model
code indicated on the nameplate attached to the sensor cable to make sure that you received the
correct sensor. For the meaning of the model code, refer to subsection 1.2.2 on page 1-3.
Note: The model and sufx code of the sensor with standard specications is as follows.
DO30G-NN-50-
- ( : User specied alphanumeric)
i
2. Information Covered by This Manual
This manual covers all of the information on handling the DO30G Dissolved Oxygen Sensor
(Style B), such as instructions on installation, inspection, and maintenance and service.
Note : When system components other than DO30G have to be mentioned, descriptions of the basic system assumes that the
DO402G Dissolved Oxygen Converter is used.
Refer to the instruction manual for information on the converter connecting holders with the
DO30G and how to connect sensor cables.
Note that the instruction manuals listed in the following table are for the associated equipment
used with the EXA
Manuals for Associated Equipment Used with the EXA DO Dissolved Oxygen Metering Syatem
Model Title of Manual Manual No.
DO402G Dissolved Oxygen Converter IM 12J05D02-01E
DO202
FLXA21 2-wire Liquid Analyzer IM 12A01A02-01E
DO30G Dissolvecl Oxygen Sensor IM 12J5B3-01E
PH8HG Guide Pipe IM 12B7M2-01E
PB350G Angled Floating Ball Holder IM 19H1E1-01E
DOX8HS Immersion Type Holder (Style B) IM 19H1D2-01E
PH8PU1 Cleaning Pump/Tank IM 19C1E1-01E
WTB10-DO
Note: Only the basic system of basic components are listed on the front panel.
Refer to respective instruction manual for information on recorders, annunciators and other instruments.
DO Dissolved Oxygen Metering System.
2-wire Dissolved Oxygen Transmitter
Relay Terminal Box IM 12J05W02-01E
IM 12J05C01-01E
Media No. IM 12J5B3-01E (CD) 4th Edition:Apr.2011 (YK)
All Rights Reserved Copyright © 1996, Yokogawa Electric Corporation
IM 12J5B3-01E
4th Edition : Apr 05,2011
u For the safe use of this equipment
CAUTION
WARNING
IMPORTANT
(1) About This Manual
• This manual should be passed on the end user.
• The contents of this manual are subject to change without prior notice.
• The contents of this manual shall not be reproduced or copied, in part or in whole, without
permission.
• This manual explains the functions contained in this product, but does not warrant that they
are suitable for the particular purpose of the user.
• Every effort has been made to ensure accuracy in the preparation of this manual. However,
when you realize mistaken expressions or omissions, please contact the nearest Yokogawa
representative or sales ofce.
• This manual does not cover the special specications. This manual may be left unchanged
on any change of specication, construction or parts when the change does not affect the
functions or performance of the product.
• If the product is not used in a manner specied in this manual, the safety of this product may
be impaired.
(2) SafetyandModicationPrecautions
ii
• Follow the safety precautions in this manual when using the product to ensure protection
and safety of the human body, the product and the system containing the product.
(3) The following safety symbols are used on the product as well as in this manual.
The following safety symbols are used in this manual.
Identies instructions that must be observed in order to avoid physical injury and electric
shock or death of the operator.
Identies instructions that must be observed in order to prevent the software or hardware
from being damaged or the system from becoming faulty.
Identies important information required to understand operations or functions.
TIP
SEE
ALSO
Identies additional information.
Identies a source to be referred to.
IM 12J5B3-01E
4th Edition : Apr 05,2011
u After-sales Warranty
l Do not modify the product.
l
During the warranty period, for repair under warranty carry or send the product to the local
sales representative or service ofce. Yokogawa will replace or repair any damaged parts and
return the product to you.
l
Before returning a product for repair under warranty, provide us with the model name and serial
number and a description of the problem. Any diagrams or data explaining the problem would
also be appreciated.
l If we replace the product with a new one, we won't provide you with a repair report.
l
Yokogawa warrants the product for the period stated in the pre-purchase quotation. Yokogawa
shall conduct dened warranty service based on its standard. When the customer site is
located outside of the service area, a fee for dispatching the maintenance engineer will be
charged to the customer.
l
In the following cases, customer will be charged repair fee regardless of warranty period.
• Failure of components which are out of scope of warranty stated in instruction manual.
• Failure caused by usage of software, hardware or auxiliary equipment, which Yokogawa did
not supply.
iii
• Failure due to improper or insufcient maintenance by user.
• Failure due to abuse, misuse or modication which Yokogawa does not authorize.
• Failure due to power supply (voltage, frequency) being outside specications or abnormal.
• Failure caused by any usage out of scope of recommended usage.
• Any damage from re, earthquake, storms and oods, lightning, disturbances, riots, warfare,
radiation and other natural changes.
l
Yokogawa does not warrant conformance with the specic application at the user site.
Yokogawa will not bear direct/indirect responsibility for damage due to a specic application.
l
Yokogawa will not bear responsibility when user congures the product into systems or resells
the product.
l
Maintenance service and supplying repair parts will be covered for ve years after the
production ends. For repair for this product, please contact the nearest sales ofce described
in this instruction manual.
IM 12J5B3-01E 4th Edition : Apr 05,2011
Blank Page
Dissolved Oxygen Metering System
Model DO30G
Dissolved Oxygen Sensor
IM12J5B3-01E4thEdition
CONTENTS
Introduction ..............................................................................................................i
u For the safe use of this equipment
u After-sales Warranty
.........................................................................................iii
...................................................................ii
1. General ...................................................................................................... 1-1
1.1 Features ............................................................................................................1-1
1.2 Specications
1.2.1 Standard Specications .....................................................................1-2
1.2.2 Model and Sufx Codes .....................................................................1-3
1.2.3 External View and Dimensions ..........................................................1-4
....................................................................................................1-2
2. Components and Their Functions .......................................................... 2-1
3. Installing the Sensor and Connecting the Cable .................................. 3-1
3.1 PreparingforInstallation ................................................................................. 3-1
3.1.1 Removal of Parts for Transportation and Storage ............................ 3-1
3.1.2 Inspecting the Permeable Membrane ...............................................3-1
3.2 Installation .........................................................................................................3-2
3.2.1 Selecting the Measurement Point ...................................................... 3-2
3.2.2 Selecting the Sensor Holder ..............................................................3-2
3.2.3 Asembling the Sensor in the Holder ..................................................3-4
3.3 Connecting the Sensor Cable ..........................................................................3-4
4. Maintenance .............................................................................................. 4-1
4.1 Routine Inspection ............................................................................................4-1
4.1.1 Inspecting the Permeable Membrane (Degree of Contamination) ...4-1
4.1.2 Checking of Membrane Assembly Locknut .......................................4-1
4.2 Inspection If Failure Occurs .............................................................................4-2
4.2.1 Inspecting the Permeable-membrane Assembly (for Damage) ........4-2
4.2.2 Checking of RTD in the Sensor ......................................................... 4-4
4.2.3 Judgment of Lead Electrode Fault ..................................................... 4-4
4.3 Expendables,SparePartsandMaintenanceParts ....................................... 4-4
4.3.1 DOX8A Maintenance Parts (Expendables) Kit ..................................4-4
4.3.2 Parts That Should Be Kept on Hand .................................................. 4-5
Appendix1"HowtoRemovetheDO30GMembraneProtectiveCap" ................................... A-1
CustomerMaintenancePartsList(DO30G) ...................................................................CMPL12J5B3-01E
CustomerMaintenancePartsList(DOX8A) ..............................................................CMPL12J05B03-12E
Revision Record ............................................................................................................................................... i
IM 12J5B3-01E
4th Edition : Apr 05,2011
Blank Page
<1. General>
F01.ai
Sensor cable
Sensor unit
Permeable-membrane
assembly
Pin-type crimping
terminals
Fork-type crimping
terminals
M4 ring-type crimping
terminals
1. General
1-1
1
1.1 Features
• The sensor maintains stable characteristics over a prolonged period.
It stabilizes in a initial time for electrolysis of approximately a half a day.
The sensor has a structure less susceptible to the effects of deterioration in an electrolyte or
contamination of the permeable membrane. Consequently, you can make precise measurements in a variety of processes.
• You can choose the desired measurement point according to the nature of the solution being measured.
You can submerse the DO30G Dissolved Oxygen Sensor to a depth of 3 m and then put it in
regular use (the sensor can withstand a pressure of up to 100 kPa). The sensor can be assembled into a immersion type holder or a oating ball holder. The sensor, when assembled
in the immersion type holder, allows automatic cleaning of the sensor with jet-sprayed water
or air at regular intervals.
• The sensor is easy to service and very economical.
Dissolved oxygen sensors usually deteriorate with time and ultimately come to the end of
their service life. For the DO30G Dissolved Oxygen Sensor, only those parts whose service
lives are relatively short, such as the membrane, may be replaced. Thus, running costs can
be reduced. In addition, servicing and maintaining the sensor requires no special skills and
is done quickly.
2
3
4
Figure 1.1 External View of the DO30G Dissolved Oxygen Sensor
Note: The crimping terminals used on the sensor cables are either pin-type, M4 ring-type or fork-type depending on specications.
IM 12J5B3-01E
4th Edition : Apr 05,2011
<1. General>
1-2
IM 12J5B3-01E
1.2 Specications
1.2.1 StandardSpecications
Object of Measurement: Concentration of oxygen dissolved in solution (water)
Principle of Measurement: Galvanic-cell method
Measurement Range: 0 to 20 ppm, 0 to 20 mg/l, or 0 to 100% (saturation)
Note: The measurement range must be entered through the dissolved oxygen converter.
Resistance Temperture Detector (RTD) :
Pt 1000
Construction: Sensor unit : Rigid PVC, SUS304
O-ring: Nitrile rubber
Permeable membrane: Fluoro-resin [FEP]
Cable shielding : Heat-resistant exible PVC
Outlet of cable : Polycarbonate resin
Sensor Cable: Length : 3 m, 5 m, 10 m, 15 m, or 20 m
(specied when ordering)
Crimping terminal conguration : Pin-type, M4 Ring-type or
Fork-type (specied when ordering )
Weight: Approx. 0.3 kg + 0.12 × N kg N: cable length
(e.g. for cable length of 5 m, approx. 0.9 kg)
Temperature of Solution Under Measurement (SUM) :
max. 0 to 40 °C
Flow rate of SUM: No less than 20 cm/s (recommended to prevent the sensor
from trapping bubbles that are the source of error in
measurements)
Pressure of SUM: Narmally : 0 to 30 kPa
Maximum applicable : 100 kPa
[Characteristics]
Repeatability:
Temperature Compensation Error:
Within ±3% FS
(including sensor) for a ±5 °C change in the range of 0 to 40 °C
Response Time : Within 2 minutes (90% response)
(including sensor)
0.1 mg/l or 3% FS, whichever is greater (including sensor)
4th Edition : Apr 05,2011
<1. General>
Model
DO30G
DO sensor
–
Always -NN
-NN
Membrane
thickness
50 Mm
-50
Cable terminal
Cable length
3m
5m
10m
15m
20m
-03
-05
-10
-15
-20
Option
Code
Suffix Code Description
Pin terminal *1
Fork terminal
M4 ring terminal *2
*1 Select pin terminal for DO402G, DO202, and FLXA21.
When terminal box is used, select WTB10-DO3.
*2 Used to connection to FLXA21.
When terminal box is used, select WTB10-DO4.
-PN
-FK
-FL
Model
DOX8A
Parts set for
maintenance
(for membrane
thickness of 50 µm)
Sensor
For membrane
replacing type sensor
-M
–
Style B
*
B
Option
Code
Suffix Code
Description
Model
DOX8W
Calibration set
Option
Code
Suffix Code Description
*
A
1.2.2 ModelandSufxCodes
1-3
• DO Sensor
•DOX8APartsSetforMaintenance
1
2
3
4
A set of zero-adjusting reagent and maintenance parts
<Contents>
Zero adjusting reagent (sodium sulte 500 g) ... 1 bottle
Membrane assembly
(for membrane thickness of 50 μm) .................3 sets
Electrolyte for sensor (50 ml) ............................. 1 bottle
Syringe for replacing electrolyte .................................. 1
Polish for silver electrode (30 g) ........................ 1 bottle
Polyethylene beaker (200 ml) ...................................... 1
•DOX8WCalibrationSet(optional)
This is necessary if the span calibration is to be done using a saturated dissolved oxygen solution. It is not necessary for air calibration.
<Contents>
Air pump, stirrer, stirring element, bubbler, clamp, beaker, and thermometer.
Note: The calibration set can be used in common regardless of the type of holder.
IM 12J5B3-01E
4th Edition : Apr 05,2011
<1. General>
ø26
ø30
ø36
ø6.5
Approx.
80
L
38.5
46
10
108
• Dissolved-oxygen sensor with
pin terminals
13
11 12 14 15 16
Model and Suffix Codes
DO30G - NN - 50 - 03 - PN
DO30G - NN - 50 - 05 - PN
DO30G - NN - 50 - 10 - PN
DO30G - NN - 50 - 15 - PN
DO30G - NN - 50 - 20 - PN
L
3 000
5 000
10 000
15 000
20 000
Weight (kg)
Approx. 0.6
Approx. 0.8
Approx. 1.4
Approx. 2.0
Approx. 2.6
• Dissolved-oxygen sensor with
fork terminals
• Dissolved-oxygen sensor with
ring terminals
Model and Suffix Codes
DO30G - NN - 50 - 03 - FK
DO30G - NN - 50 - 05 - FK
DO30G - NN - 50 - 10 - FK
DO30G - NN - 50 - 15 - FK
DO30G - NN - 50 - 20 - FK
L
3 000
5 000
10 000
15 000
20 000
Weight (kg)
Approx. 0.6
Approx. 0.8
Approx. 1.4
Approx. 2.0
Approx. 2.6
L
3 000
5 000
10 000
15 000
20 000
Weight (kg)
Approx. 0.6
Approx. 0.8
Approx. 1.4
Approx. 2.0
Approx. 2.6
Unit: mm
Pin terminals
Fork terminals
Ring terminals
Terminal asign
13 IE
15 RE
11 T1
12 T2
14 Shield
16 Liquid earth
Model and Suffix Codes
DO30G - NN - 50 - 03 - FL
DO30G - NN - 50 - 05 - FL
DO30G - NN - 50 - 10 - FL
DO30G - NN - 50 - 15 - FL
DO30G - NN - 50 - 20 - FL
13111214 15 16
13111214 15 16
1.2.3 External View and Dimensions
1-4
Note: Select pin terminasl for systems using the DO402G/FLXA21 dissolved oxygen converter.
When using with FLXA21, M4 ring terminals is recommended.
Figure 1.2 External View and Dimensions of DO30G Dissolved Oxygen Sensor
IM 12J5B3-01E
4th Edition : Apr 05,2011
<2. Components and Their Functions>
Sensor cable
Carries the detected signal to
the dissolved oxygen converter.
The desired cable length can be
chosen from 3, 5, 10, 15, or 20m.
You can choose either pin-type, M4
ring-type or fork-type terminals.
Permeable-membrane
assembly locknut
Sensor unit
Generates both an electrolytic current signal
proportional to the amount of oxygen that
passes through the permeable membrane
and a temperature signal for compensation.
O-ring
Lead electrode
Permeable-membrane assembly
Silver electrode
Temperature Detector
Cutaway View of the Sensor Tip
F03.ai
CAUTION
2. Components and Their Functions
2-1
1
2
3
4
Figure 2.1 Components and Their Functions of DO30G Dissolved Oxygen Sensor
Do not loosen the permeable-membrane assembly locknut except when replacing the assembly.
IM 12J5B3-01E
4th Edition : Apr 05,2011
Blank Page
<3. Installing the Sensor and Connecting the Cable>
Permeable-membrane assembly locknut
Make sure the locknut is not loose.
Permeable membrane
Make sure the membrane is free
from any wrinkling or damage.
F04.ai
3. Installing the Sensor and
Connecting the Cable
3-1
1
2
3.1 PreparingforInstallation
3.1.1 RemovalofPartsforTransportationandStorage
A cap to prevent the membrane from being damaged when transporting the sensor is mounted at
the tip of the DO30G Dissolved Oxygen Sensor. When installing the sensor, remove this protec-
tive cap (See Appendix 1.).
3.1.2 InspectingthePermeableMembrane
Any wrinkling or damage to the permeable membrane may lead to a failure to take normal measurements. Make sure the membrane is free from any wrinkling or damage.
Also check that the membrane assembly locknut is not loose. If any wrinkling or damage is found,
replace the membrane assembly with a new assembly unless such damage is slight.
3
4
Figure3.1 InspectionofPermeable-membraneAssembly
IM 12J5B3-01E
4th Edition : Apr 05,2011
<3. Installing the Sensor and Connecting the Cable>
3-2
IM 12J5B3-01E
Stopper
Guide pipe
Dissolved oxygen sensor
Sensor cable
Mounting pipe
(Outer diameter of 60.5 mm)
F05.ai
3.2 Installation
Normally, the DO30G Dissolved Oxygen Sensor is assembled into the PH8HG Guide Pipe,
PB350G Angled Floating Ball Holder or DOX8HS Immersion Type Holder and submersed to the
point best suited to obtain precise measurement results. This section explains how to select the
measurement point and sensor holder.
3.2.1 SelectingtheMeasurementPoint
Normally, a location that meets the following requirements may be selected as the measurement
point.
l The measured value is representative among the values available for the solu-
tion under measurement (SUM).
Avoid choosing a location where the solution is unevenly distributed, since heavy hunting may
result in the measured value. Also, avoid locations where bubbles occur frequently.
l Thetemperatureandowratecomplywiththeoperatingconditionsrequired
of the sensor and holder.
Note that, if a measured solution running at a high ow rate contains particles of sand, the permeable membrane of the sensor may be damaged.
Do not install the sensor at a depth greater than 3 m.
3.2.2 Selecting the Sensor Holder
Each holder or tting where the DO30G Dissolved Oxygen Sensor is assembled has the following characteristics.
Choose a holder that suits the liquid to be measured and the measurement location.
[PH8HGGuidePipe]
The holder is made of PVC resin and is 2 m long. The sensor is suspended down inside the cylindrical barrel of the holder. This pipe is conveniently suited for the measurement of a solution free
from bubbles or pollutants.
Figure3.2 SuspensionofDissolvedOxygenSensorUsingPH8HGGuidePipe
4th Edition : Apr 05,2011
<3. Installing the Sensor and Connecting the Cable>
Arm assembly
Sensor cable
Float
Mounting bracket
Fix the bracket to a nominal 50 A
pipe (OD of 60.5 mm) or a
horizontal surface (floor, the
edge of a solution tank, etc.).
F06.ai
Cleaning-utility pipe
Sensor cable
Dissolved oxygen sensor
Jet cleaner
F07.ai
[PB350GAngledFloatingBallHolder]
3-3
The tting is designed to contain the sensor in a sphere that oats on a liquid. This tting is immune to large variations in the liquid level. Since the wet part is smooth and less susceptible to
catching ocs, the sensor does not trap rubbish that mixes in with the SUM (Related description: See Subsection 3.2.3). The oat is supported by an arm and does not move away from the
measurement point even if the SUM is owing.
When using this holder the membrane damage detector function in the converter can be activated.
Figure3.3 SuspensionofDissolvedOxygenSensorUsingPB350GAngledFloatingBallHolder
1
2
3
4
[DOX8HS(StyleB)ImmersionTypeHolder]
The holder holds the sensor at an angle of 45°. Consequently, bubbles will not stick to the permeable membranne. Any pollutants in the SUM can be automatically cleaned off at regular intervals
using a jet-spray water (air) cleaner.
Figure3.4 SuspensionofDissolvedOxygenSensorUsingDOX8HSImmersionTypeHolder
(withJetCleaner)
IM 12J5B3-01E
4th Edition : Apr 05,2011
<3. Installing the Sensor and Connecting the Cable>
CAUTION
Stopper
F07-1.ai
F08.ai
IE T1 T2 SE RE S
131721 11 12 14 15 16
13 11 12 14 15 16
(*1)
Dissolved oxygen
converter terminals for
connection to sensor
cable
Sensor cable
Jumper
*1: Liquid earth to detect membrane failure.
This function is available when using
PB350G/PB360G float type holder.
Connect only when using this function.
3.2.3 Asembling the Sensor in the Holder
For details on how to assmble the sensor in the holder or tting, see the appropriate instruction
manual for each holder or tting.
Exercise care not to contaminate or wet the tip of the sensor cable when assembling the sensor.
If you will not begin wiring the sensor cable immediately, take the protective measures necessary
to prevent the assembly from being damaged.
SensormountinginthecasewhereocsandothermatterarecontainedintheSUM
3-4
The stopper projecting from the membrane assembly locknut serves to prevent the membrane
from being in contact with the ground and thus being damaged. If there are ocs in the SUM, the
stopper may become clogged. Thus, assemble the sensor to the holder so that the stopper is
positioned downstream in the SUM.
3.3 Connecting the Sensor Cable
The cable of the dissolved oxygen sensor must be connected to the terminals of the dissolved
oxygen converter. For information on connections, refer to the following instruction manu-
als: DO402G Dissolved Oxygen Converter (IM 12J05D02-01E), the DO202/FLXA21 2-wire
Transmitter instruction manual (IM 12J05C01-01E/IM 12A01A02-01E) or WTB10-DO
Terminal Box (IM 12J05W02-01E).
Relay
Figure3.5 ConnectionofSensorCable
Now the explanation on the installation and wiring is completed. For details on operation during
startup or for regular operation after the entire measuring system is brought into operation, refer
to the DO402G Dissolved Oxygen Converter instruction manual (IM 12J05D02-01E), the DO202/
FLXA21 2-wire Transmitter instruction manual (IM 12J05C01-01E/IM 12A01A02-01E). The main-
tenance and service of the dissolved oxygen sensor is explained in Section 4 that follows.
IM 12J5B3-01E
4th Edition : Apr 05,2011
<4. Maintenance>
CAUTION
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 DO402G Dissolved Oxygen Converter instruction manual (IM
12J05D02-01E), the DO202/FLXA21 2-wire Transmitter instruction manual (IM 12J05C01-01E/
IM 12A01A02-01E).
4-1
1
2
3
4.1 Routine Inspection
4.1.1 InspectingthePermeableMembrane(Degreeof
Contamination)
An inspection (visual) of the permeable membrane must be made whenever the sensor is calibrated. 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 membrane 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.
Exercise care to avoid wrinkling or damaging the permeable membrane during inspection.
Wrinkling and other damage prevent normal membrane operation.
4.1.2 CheckingofMembraneAssemblyLocknut
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.
4
IM 12J5B3-01E
4th Edition : Apr 05,2011
<4. Maintenance>
4-2
IM 12J5B3-01E
CAUTION
4.2 Inspection If Failure Occurs
If the electrolyte and/or lead electrode within the sensor unit deteriorates and ultimately completes its service life, anomalies, such as the failure to make a span adjustment, will occur. This
section deals especially with the inspection and service of the dissolved oxygen sensor needed if
any anomaly is found in a detected signal. If you fail to pinpoint the cause of failure to a particular
location, follow the instructions in Section 4.2.1 and subsequent sections in sequence. One or
more of the following measures are necessary to remedy the failure.
• Replacement of electrolyte/permeable-membrane assembly
• Replacement of sensor unit
4.2.1 InspectingthePermeable-membraneAssembly(for
Damage)
Note : When the membrane is used in the oat holder, the converter membrane damage detector function can be used. This function
generates an "E4" error message if the membrane is damaged.
Check the permeable-membrane assembly for possible wrinkling or damage. Also, check that
the permeable-membrane assembly locknut is not loose. If the locknut is securely tightened and
the membrane is normal (no wrinkling or damage is found), proceed to the instruction procedure
in Section 4.2.2. If the locknut is loosen or the membrane is wrinkled or damaged, replace the
electrolyte and the permeable-membrane assembly (including the O-ring seal) as well.
[Electrolyte/permeable-membraneassemblyreplacementprocedure]
When replacing the electrolyte and permeable-membrane assembly, you must provide a syringe
and beaker that are used to replace the electrolyte and an abrasive and gauze to polish the silver
electrodes. Provide these materials along with the spare electrolyte solution and assembly used
in the replacement.
PrecautionsinHandlingtheElectrolyte
The potassium-hydroxide electrolyte (KOH) is a highly alkaline solution containing potassium
hydroxide as the major constituent. Exercise extreme care to protect your body from contact
with the solution and to prevent the solution from getting into your eyes. Should your skin or eyes
become exposed to the solution, immediately wash the exposed area with clean water. If the
solution gets in your eyes, consult an eye doctor after ushing them with water. The electrolyte
is a colorless corrosive and, therefore, there is the risk of its being mishandled. Never leave any
residual solution in the syringe.
(1) After having removed the dissolved oxygen sensor from the holder, clean dirt off the wet
part.
(2) Loosen the locknut and remove the permeable-membrane assembly. Also, remove the O-
ring.
4th Edition : Apr 05,2011
<4. Maintenance>
Sensor unit
Place a beaker
underneath to catch the
draining electrolyte.
Silver electrode
Syringe
Inlet for refilling electrolyte
Needle (syringe needle)
Insert the syringe needle into
the inlet for refilling electrolyte
and force air inside.
F09.ai
Surface of the silver electrode
Apply a drop of electrolyte when
installing the permeable-membrane
assembly.
Fill with electrolyte
and then remove
approximately 1 ml.
Syringe
Inlet for injecting electrolyte
O-ring
F10.ai
(3) Completely drain the electrolyte within the sensor unit. Tilt the sensor tip downward and then
use the syringe to force air into the inlet for relling the electrolyte. Position the beaker so it
will catch any of the electrolyte that drains through the gaps around the silver electrode.
Figure 4.1 Draining the Electrolyte
(4) Hold the sensor level and polish the silver electrode.
Apply an abrasive (alumina) to wet gauze and polish the surface of the silver electrode until
it becomes glossy. After nishing polishing, completely wipe off any abrasive that remains
on the electrode.
4-3
1
2
3
4
(5) Make sure the sealed surfaces are free from dust. Install a new O-ring.
(6) Inject 8 ml of electrolyte into the sensor body with the syringe (see Figure 4.2).
Note: Always use an electrolyte prepared by Yokogawa for exclusive use with the DO30G.
First, ll the sensor with the electrolyte (approx. 9 ml) and then remove approximately 1 ml
so that a layer of air is present inside the sensor body.
(7) Install the permeable-membrane assembly.
It is strictly not possible to allow a layer of air to form between the membrane and the sil-
ver electrode. To prevent such a layer from forming, rst apply a drop of electrolyte to the
surface of the silver electrode. Lightly press the permeable-membrane assembly so that the
O-ring touches the groove on the inside. Tighten the locknut fully without letting the assembly turn.
Figure 4.2 Injecting the Electrolyte
All these steps complete the inspection procedure for the permeable-membrane assembly. By
way of precaution, make sure the membrane is free from wrinkling. Note that a stable detection
signal is not possible right after relling with the electrolyte. Make a zero or span adjustment approximately a half a day or longer after relling. It may indicate a minus value for about 10 min-
utes zero adjustment.
IM 12J5B3-01E
4th Edition : Apr 05,2011
<4. Maintenance>
4-4
IM 12J5B3-01E
4.2.2 Checking of RTD in the Sensor
The resistance temperature detector (RTD) incorporated in the DO30G sensor is a Pt 1000 Ω
RTD. This Pt 1000 Ω RTD indicates a resistance value of about 1097 Ω at 25 °C. Check the RTD
by measuring the resistance value between conductors 11 (T1) and 12 (T2). If the resistance
value differs greatly from the above value, the sensor must be replaced.
4.2.3 JudgmentofLeadElectrodeFault
If no failure is found in the checks in Subsections 4.2.1 and 4.2.2, the cause of the problem may
be the end of the service life of the lead electrode or a loose connection of the conductors. In
either case, the sensor must be replaced.
[ServiceLifeofLeadElectrode]
The lead electrode mounted in the sensor body gradually erodes due to battery action. When
span adjustment becomes impossible for a sensor which has been used in succession over a
long period even if the electrolyte/membrane assembly has been replaced, it shows that the lead
electrode has reached the end of its service life. The service life of the lead electrode varies with
the temperature of the SUM or the amount of dissolved oxygen. Under general operating conditions, it should be approximately three to four years.
4.3 Expendables,SparePartsand
MaintenanceParts
This section presents the general information on spare parts that the manufacturer recommends
you to provide and on materials that are used in maintenance and service. When procuring these
parts or materials, also refer to the Customer Maintenance Parts List (CMPL) at the end of this
manual.
4.3.1 DOX8AMaintenanceParts(Expendables)Kit
The DOX8A Maintenance Parts Kit contains, as a set, spare parts for the expendables that need
to be replaced within one year after the start of use of the DO30G Dissolved Oxygen Sensor, the
materials that are used during replacement, and a reagent that is used to prepare the calibration
solution for zero adjustment.
Note: There are two different DOX8A Maintenance Parts Kit available: style A and style B.
Be sure to use a style B membrane assembly (membrane thickness: 50 μm) for a EXA DO dissolved oxygen metering system.
4th Edition : Apr 05,2011
<4. Maintenance>
Table4.1ItemsContainedintheDOX8AMaintenancePartsKit
4-5
Item PartNo. Qty Remarks
Electrolyte K9171DN 50 ml
Permeable-membrane
assembly / O-ring
Reagent for preparing calibration solution (for zero adjust-
ment)
sodium sulte (Na
5-ml syringe (without needle)
Needle
200-ml beaker L9825AF 1
Abrasive for silver electrode
(alumina)
2SO3
)
K9171HM
L9920BR
L9827NH
L9827NG11
K9088PE
3 sets
500 g
30 g
Must be replaced periodically, either once every 6 to 8
months or if a span adjustment is not possible. Eight to 9
ml are consumed with each replacement.
Normally, these parts must be replaced at the same time
that the sensor is relled with electrolyte. If the sensor is used in a slurry solution, these parts may require
replacement more often due to abrasion or damage.
Calibration must be carried out at a predetermined
interval (the frequency of calibration varies depending
on the operating conditions). Calibration must also be
performed when, for example, the electrolyte is replaced.
Approximately 15 grams of the reagent is needed to prepare 1 liter of the calibration solution for zero adjustment.
Used when replacing the electrolyte.
Used when calibration is carried out or when the electrolyte is replaced.
When the permeable-membrane assembly is replaced,
the silver electrode must be polished until it becomes
glossy. Only an extremely marginal amount (approx. 0.5
mg) of the abrasive is consumed with each polishing.
4.3.2 PartsThatShouldBeKeptonHand
1
2
3
4
Even parts with a long service life are not completely free from possible failure. It is recommended that users have on hand spare parts for those parts which, if they become defective, will make
it impossible to continue measurement.
[MembraneAssemblyLocknut(partnumber:K9171CH)]
It is recommended that users have spare parts for the locknut on hand in preparation for possible
failure.
[SpareSensorAssembly]
If the sensor assembly remains unused over a prolonged period, the electrolyte may change in
quality or some anomalies may occur in the permeable membrane. Consequently, these materials must be replaced with new ones before you can use the sensor. Although it is desirable
that users always try to avoid storing the sensor assembly for long periods, the manufacturer
recommends that users keep a spare part on hand for the sensor assembly in anticipation of an
unexpected failure. Do not store the sensor with the electrolyte removed. Otherwise, any residual
electrolyte may become concentrated, harming the lead electrode or other mechanisms. If the
sensor must be stored with the electrolyte removed, completely clean the inside of the sensor
with clean water (repeat injecting and draining the water several times) before it is stored.
Note: If the sensor is stored without the electrolyte, repeat injecting and draining the electrolyte several times before you reuse it.
IM 12J5B3-01E
4th Edition : Apr 05,2011
Blank Page
<Appendix 1.>
CAUTION
Prohibited action 1
No good
No good
Prohibited action 2
DO30G
Protective cap
A-1
Appendix 1. How to Remove the DO30G Membrane Protective
Cap
A black rubber cap is attached to the tip of the DO30G to protect the membrane.
Pulling off the cap forcefully causes a negative pressure inside the protective cap, because the
protective cap sticks to the DO30G, and may stretch the membrane or damage it.
Furthermore, removing the cap by twisting it may loosen the membrane assembly and affect the
measurement results.
Please read the following notes and removal procedure in advance in order to prevent damage
and loosening of the membrane assembly from occurring.
1. Prohibited actions
2. How to Remove Protective Cap
Figure 1 Do not pull off the cap forcefully
When taking out of the package, a black rubber cap is attached the DO30G shown below.
Figure 3 Condition after taking out of the package
Figure 2 Do not pull off the cap twisting the cap
counterclockwise.
IM 12J5B3-01E
3rd Edition : May 28,2010
<Appendix 1.>
Protective
cap
Stick or the like
with a diameter of
0.1 to 0.2 mm
Push it beneath the protective cap
and up to the tip of the sensor.
DO30G tip
Protective cap
Maintain the space.
Turn it clockwise slowly.
A-2
When using a stick or the like.
(1) As shown in the gure 4, insert a
stick or the like between the DO30G
and protective cap. Be careful not to
damage the DO30G main body.
Figure 4 Insert a stick or the like between the
DO30G
(2) Push it in so that enough air space
is created between the DO30G and
protective cap.
When an appropriate stick or the
like is not available.
(1) Hold the protective cap while holding the
DO30G as shown in the gure 7.
Figure 7 Hold the DO30G and protective cap.
(2) Remove the protective cap by turning it
clockwise slowly.
Figure 5 Push a stick or the like beneath the
protective cap to create air space.
Figure 6 Pull off the protective cap while
maintaining the air space.
Figure 8 Remove the protective cap by turning it
clockwise slowly
IM 12J5B3-01E
3rd Edition : May 28,2010
Customer
2
3
1
Dissolved Oxygen Metering System
Maintenance
PartsList
DO30G
Dissolved Oxygen Sensor
Item Part No. Qty Description
1 — 1 Dissolved oxygen sensor
2 K9171CH 1 Box nut assembly
3 K9171HM 1 Membrane / O-ring
Model SufxCode Option Code Description
DO30G
— -NN
Membrane thickness -50
Cable length
Cable terminal
…………………… ……………………
……………………
……………………
03
-
-05
-10
-15
-20
……………………
……………………
……………………
……………………
……………………
……………………
-PN
……………………
-FK
……………………
-FL
Dissolved oxygen sensor
Always - NN
50 µm
3 m
5 m
10 m
15 m
20 m
Pin terminal
Fork terminal
M4 ring terminal
(Refer to table of below "Model & Code")
All Rights Reserved, Copyright © 1996, Yokogawa Electric Corporation.
Subject to change without notice.
CMPL12J5B3-01E
3rd Edition : Oct,2010
Customer
1
2
3
4
78
9
65
10
200
150
100
50
Item Part No. Qty Description
1 L9825AF 1 200 ml Beaker
2 L9920BR 1 Reagent (for zero calibration)
3 K9088PE 1 Polishing Powder
4 K9171HK 1 Spare Parts & Service Tool
5 K9171DN 1 Electrolyte
6 K9171HM 3 Membrane / O-Ring Set
7 G9303NM 1 O-Ring
8 K9171CS 1 Membrane Assembly (50 mm)
9 L9827NG 1 Needle
10 L9827NH 1 5 ml Sylinge
Maintenance
Parts List
Model DOX8A-M*B
Accessory for EXA DO
All Rights Reserved, Copyright © 1996, Yokogawa Electric Corporation.
Subject to change without notice.
CMPL 12J05B03-12E
2nd Edition : Feb. 2006 (YK)
Revision Record
l Title : Model DO30G Dissolved Oxygen Sensor
l Manual No. : IM 12J5B3-01E
Edition Date Remark(s)
1st Nov. 1996 Newly published
2nd May 2007 Fully revised
3rd Mar. 2010 MS-code of DOX8A, DOX8W added to Section 1.2.2.
CMPL 12J05B03-12E(2) added for DOX8A.
4th Apr. 2011 Over all revised.
P. i, FLXA21 and DO202 manual no. added to documnents to
be refered.
P. 1-1, Stabilized time in a initial time for electrolysis modied.
M4 ring terminal added to Figure 1.1.
P. 1-2, M4 ring-type terminal added to specications.
P. 1-3, FLXA21 added to MS-code.
P. 1-4, M4 ring terminal added to Figure 1.2.
P. 2-1, M4 ring terminal added to Figure 2.1.
P. 3-1, Addition of Appendix 1 to be refered for section
3.1.1 "Removal of Parts for Transportation and
Storage."
P. 3-4, FLXA21 and DO202 manual no. added to section 3.3
"Connecting the Sensor Cable."
P. 4-1, FLXA21 and DO202 manual no. added to section 4
"Maintenance."
P. 4-3, Stabilized time in a initial time for electrolysis modied.
Appendix 1 "H ow to R emo ve the DO30G Mem bra ne
Protective Cap" added to end of this manual.
CMPL 12J5B3-01E revised to 3rd edition (M4 ring terminal
added)..
i
IM 12J5B3-01E
4th Edition : Apr 05,2011
Blank Page
Loading...