YOKOGAWA DO72 User manual

Instruction
Manual
Model DO72
Optical Dissolved Oxygen Sensor
IM12J06J02-00EN-P
4th edition

Safety and Modication Precautions
• In order to protect the system controlled by the product and the product
itself and ensure safe operation, observe the safety precautions describe
in this instruction manual. We assume no liability for safety if users fail to
observe these instructions when operating the product.
• IfthisinstrumentisusedinamannernotspeciedinthisInstruction
manual, the protection provided by this instrument may be impaired.
• If any protection or safety circuit is required for the system controlled by the
product or for the product itself, prepare it separately.
• Be sure to use the spare parts approved by Yokogawa Process Analyzers
Europe B.V. (hereafter simply referred to as YOKOGAWA) when replacing
parts or consumables.
• Modicationoftheproductisstrictlyprohibited.
• The following safety symbols are used on the product as well as in this
manual.
WARNING
This symbol indicates that an operator must follow the instructions laid out in this
manual in order to avoid the risks, for the human body, of injury, electric shock, or
fatalities. The manual describes what special care the operator must take to avoid
such risks.
CAUTION
This symbol indicates that the operator must refer to the instructions in this manual
in order to prevent the instrument (hardware) or software from being damaged, or a
system failure from occurring.
CAUTION
This symbol gives information essential for understanding the operations and func-
tions.
NOTE
This symbol indicates information that complements the present topic.
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Notes on Handling Instruction manuals
• Please hand over the Instruction manuals to your end users so that they can
keep the Instruction manuals on hand for convenient reference.
• Please read the information thoroughly before using the product.
• The purpose of these Instruction manuals is not to warrant that the product
is well suited to any particular purpose but rather to describe the functional
details of the product.
• No part of the Instruction manuals may be transferred or reproduced
without prior written consent from YOKOGAWA.
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manuals and product at any time, without notice or obligation.
• Ifyouhaveanyquestions,oryoundmistakesoromissionsinthe
Instruction manuals, please contact our sales representative or your local
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Product Disposal:
The instrument should be disposed of in accordance with local and national legisla-
tion/regulations.

Contents
1. PREFACE...........................................................................................5
1.1 Introduction ................................................................................5
1.2 Unpacking and Checking ..........................................................5
1.3 Warranty and Service ................................................................5
1.4 Serial number..............................................................................6
2. GENERAL SPECIFICATIONS ...........................................................7
2.1 Measuring elements: ................................................................7
2.2Electricalspecications ..............................................................7
2.3Mechanicalspecications..........................................................7
2.4 Performance................................................................................7
2.5 Shipping details ..........................................................................8
2.6 Environmental conditions .........................................................8
2.7 Regulatory compliance ..............................................................9
3. INSTALLATION OF DO72 .............................................................10
3.1 Installation in sensor holder ...................................................10
3.1 Preparing the sensor for use .................................................10
3.2 Mounting the sensor ...............................................................10
4. DIMENSIONS.................................................................................14
5. WIRING..........................................................................................15
5.1 DO72 optical DO sensor grounding.......................................16
6. GENERAL CALIBRATION & MAINTENANCE PROCEDURE ..........17
6.1 Pre-Calibration Input................................................................17
6.2 DO72 two-point (Re)calibration .............................................17
6.3 Maintenance of the DO71 sensor ..........................................19
7. MODEL AND SUFFIX CODES.........................................................21
8. SPARE PARTS .................................................................................22
9. CHEMICAL COMPATIBILITY .........................................................23
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1. PREFACE
1.1 Introduction
The DO72 optical dissolved oxygen sen-
sor uses the optical measurement meth-
od to continuously measure oxygen
dissolved in water in various industries
and applications where accurate mea-
surement and control is required.
The optical sensor is integrated in a
exchangeable stainless-steel cap that is
screwed to the probe housing.
These extremely robust probes can be
installed in various applications. The op-
tical sensors have a fast response time &
good long-term stability with low main-
tenance and low costs of ownership.
The DO72 sensor is available for ppm
range and ultra trace ppb range oxygen
measurements. The interface used is
Bi-directional digital communication
RS485 and can be connected directly
to the new FLXA402 4-Wire converter.
Converter is designed to combine the
superior functionality and ease of use
from the Yokogawa FLXA series with the
digitization of the future.
The DO72 sensor is ideally suited for
industry applications where it must
stand harsh measurement conditions.
They are delivered in 120mm length
and have a sensor cap that can easily be
exchanged.
1.2 Unpacking and Checking
Upon arrival of the purchased product,
carefully unpack it and make sure the
product has not been damaged during
transportation. Verify the model code on
a name label adhered on the packaging
box. For details of the model code, see
subsection 7.
1.3 Warranty and Service
Yokogawa products and parts are
guaranteed free from defects in work-
manship and material under normal
use and service for a period of (typically)
12 months from the date of shipment
from the manufacturer. Individual sales
organizations can deviate from the typ-
ical warranty period, and the conditions
of sale relating to the original purchase
order should be consulted. Damage
caused by wear and tear, inadequate
maintenance,corrosion,orbytheeects
of chemical processes are excluded from
this warranty coverage. In the event
of warranty claim, the defective goods
should be sent (freight paid) to the
Service Department of the relevant sales
Organization for repair or replacement
(at Yokogawa’s discretion).
The following information must be
included in the letter accompanying the
returned goods:
• Model Code and Serial Number.
• Original Purchase Order and Date.
• Length of time in service and descrip-
tion of the process.
• Description of the fault and circum-
stances of the failure.
• Process/environmental conditions
that may be related to the failure of the
sensor
• Statement as to whether warranty or
non-warranty service is requested.
• Complete shipping and billing instruc-
tions for return of material, plus the
name and phone number of a contact
person that can be reached for further
information.
• Clean Statement
Returned goods that have been in
contactwithprocessuidsmustbe
decontaminated and disinfected prior to
shipment. Goods should carry a certif-
icatetothiseect,forthehealthand
safety of our employees. Material Safety
Data sheets must be included for all
components of the process to which the
sensor(options) have been exposed.

1.4 Serial number
TheSerialnumberisdenedbynine(9)alphanumeric
characters:
X1X2 Production location
X3X4Year/Month code
X5X6X7X8X9 Tracking number
Example: N3X380005
Table 1: Production Year code
Year Year code Year Year code
2014 P 2026 3
2015 R 2027 4
2016 S 2028 5
2017 T 2029 6
2018 U 2030 7
2019 V 2031 8
2020 W 2032 9
2021 X 2033 A
2022 Y 2034 B
2023 Z 2035 C
2024 1 2036 D
2025 2 2037 E
Month Month code
January 1
February 2
March 3
April 4
May 5
June 6
July 7
August 8
September 9
October A
November B
December C
Table 2: Production Month code
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2. GENERAL SPECIFICATIONS
2.1 Measuring elements:
Optical dissolved oxygen sensor in probe body and an oxygen exchange cap (OEC).
2.2 Electrical specications
Output signal: Bi-directional digital communication
Physical layer: RS485
Protocol: MODBUS, RTU mode
Data rate: Default 19200 b/s (8, No Parity, 2 stop bits)
Power supply: +7 … +30 VDC
Max. 1W in active mode
< 150mW in stand-by mode
Cable: WU10 with one side wired pins and the
other side VarioPin connector
2.3 Mechanical specications
Case/OEC:    StainlessSteel (1.4435),Ra<0.4μm)
OEC sealings / material: O-ring EPDM
OEC sealing dimensions mm (inch): ID 9x1 (0.35x0.03)
Shaft sealing mm (inch): ID 11x3 (0.43x0.11)
Housing size (LxDiam.): 120x12 mm (4.17x0.47)
Weight: Min. 100g (0.22 lbs)
Sensor mounting system: Sensor PG13.5 thread
Sensor connection: VarioPin, 8 pins
2.4 Performance
DO72-W Wide measuring range sensor characteristics
Measuring range: 0 – 22.5 mg/L O2
Accuracy: ± 0.05 mg/L or 1% of reading
whichever greater
Repeatability ± 0.05 mg/L or 1% of reading
whichever greater
Temperature accuracy: ≤1.0°C (≤1.8°F)1
DO72-T Trace measuring range sensor characteristics
Measuring range: 0 - 2 mg/L O2
Accuracy: ± 3 ppb or 3% of reading
whichever greater
Repeatability ± 3 ppb or 3% of reading
whichever greater
Temperature accuracy: ≤1.0°C (≤1.8°F)1

Common characteristics
Operating temperature: 0 °C to + 50 °C (0 to 122°F)
Pressure: 0 to 12 Barg (0 to 174 psi) (overpressure);
0 to 0.990 Barng (0 to 14.36 psi) (under pres
sure)
Flow rate 2 m/sec or less2
Response time t90 ≤90 sec.3
Ingress protection IP X8 according EN 60529:1991/A1:2000/
A2:2013
O-ring of OEC must be replaced once a year
2.5 Shipping details
Package size (LxWxH) Approx. 300x100x75 mm
(11.8x3.9x3.0 inch)
Package weight (max.)
Sensor Sensor weight g (lbs) Total package weight g (lbs)
DO72-W/-T 108 (0.23) g (lbs) 272 (0.59)g (lbs)
OEC CA/CB/CC 6 (0.01) g (lbs) 147 (0.32) g (lbs)
2.6 Environmental conditions
Storage temperature -10 to +70°C (-14 to 158°F)4
Ingress protection IP X8 according EN 60529:1991/
A1:2000/A2:2013
O-ring of OEC must be replaced once a year
Installation Overvoltage Category I
Pollution Degree 2
Altitude 2000 m or less (6561.68 feets)
(at20°C(68°F),960-980hPa(13.92to14.21psi),humidiedgasmixtures,afterper-
forming a calibration)
Note 1: Temperature measurement for process compensation only
Note2: Hiowratecaninuencesensorperformance
Note3: Fromairsaturatedwaterto0g/Lwater(e.g.preparedby1%sodiumsultesolution)
Note 4: Storage stability of the oxygen exchange cap is 5 years if stored under dark and dry
conditions at 20°C (68°F)
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2.7 Regulatory compliance
CE
CE/Directive: 768/2008/EC
     CE-markhasbeenaxedontheproductin 
2021 for the First time
UKCA     UKCA-markhasbeenaxedontheproduct 
     in2021forthersttime.
EMC
Directive: 2014/30/EU
Standards: EN 61326-1:2013; IEC 61326-1:2012
Table 2 (for use in industrial locations)
EN 55011:2016/A1:2017; CISPR11: 2015/
A1:2016
Group 1, Class B (for use in domestic estab
lishments)
Approvals ACMA
China GB30439
LVD
Directive: 2014/35/EU
Standards: NEN-EN-IEC 61010-1:2010/A1:2019;
NEN-EN-IEC 61010-2-030:2010/C1:2011
RoHS2
Directive: 2015/863/EU
Commission Delegated Directive (EU)
2015/863 amending Annex II as regards
the list of restricted substances, and by
applying Annex IV as regards the application
of sensors, detectors, and electrodes, by
applying the following standards:
EN-IEC 63000: 2018: Technical documenta
tion for the assessment of electrical and
electronic products with respect to the re
striction of hazardous substances.
Label information:
All statutory required label information as well as model name, model code and se-
rial number are printed on sensor body using laser technique as shown in example
below.

3. INSTALLATION OF DO72
Using sensor adapters the DO72 optical
dissolved oxygen sensor can be assem-
bledintoanyYokogawaoworimmer-
sion/oatingtting,like:FF20,FF40ow
tting,thePB350Gangledoatingball
holder,PB360Gverticaloatingballhold-
er, or DOX8HS submersion type holder.
Fitting assembly asures sensor to be sub-
merged to the optimum point to obtain
precise measurements.
The DO72 can be also mounted to
processandexistingttingproductline
using standard adapters.
3.1 Installation in sensor holder
An adaptor (optional Fig. 4) is necessary
to assemble DO72 into the DOX8HS sub-
mersion type holder (see Fig. 1), PB350G
angledoatingballholder(seeFig.2),or
PB360Gverticaloatingballholder(see
Fig. 3).
For mounting the sensor into the FF20
andFF40owttingusesensoradapter
asdescribedingure5,6and7.
3.1 Preparing the sensor for use
Make sure that the Oxygen Exchange
Cap (OEC) is screwed tightly to the probe
body and did not work loose while han-
dling the probe.
3.2 Mounting the sensor
Chooseaholder/ttingthatsuitsthe
liquid to be measured and the measure-
ment location.
Note: 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.
Note that, if a measured solution run-
ningatahighowratecontainsparticles
of sand, the permeable membrane of the
sensor may be damaged.
Fig. 1: DOX8HS submersion type holder
Fig. 3: PB360Gverticaloatingball
holder
Fig. 2: PB350G/PB30angledoatingball
holder
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Fig. 4:AdapterforinstallingDO72intosubmersibleandoatingballholder
Optical dissolved oxygen sensor
DOX8HS Submersion type holder
Place an O-ring here. Adaptor for submersible
type holder
Adaptorforoatingtype
holder

Figure 5.DO72installationinYokogawaFF20tting6using the adapter K1520JN,
K1500DV or K1520JP
Adapter K1520JN /
K1500DV / K1520JP
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Figure 6. DO72 installation in FF40/
FS40tting6using the adapter K1520JN,
K1500DV or K1520JP
Figure 7. DO72 Installation in SC4A SS
owtting6using the adapter K1523JB,
K1523JD
Adapter K1520JN /
K1500DV / K1520JP
Adapter K1523JB /
K1523JD
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4. DIMENSIONS
Fig. 8. Dimensions DO72 in mm
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5. WIRING
DO72 Sensor cable connection to converter is delivered with wire pin end. For infor-
mation on DO72 sensor cable connection to FLXA402, refer to the user’s manual for
FLXA402 4-Wire Converter (IM12A01F01-02EN).
Fig. 10. D6 module terminal assignment for DO72 dissolved oxygen sensor
Table 3: Pin terminal wiring numbering
Fig. 9. Connection diagram – WU10-V-D (left) and DO72 sensor wiring details (from
FLXA402 manual - right)
Wire Pin no. VP pin Wire color Description
11 G Yellow RS485 Data (A)
12 H Green RS485 Data (B)
13 D White (Coax2 shield) GND
10 C White (Coax2 core) 7 – 30 VDC
14 S Black cable shield / probe body
Remark: Cables which are not used should be connected to any terminal of some-
where between 15 to 18.

5.1 DO72 optical DO sensor
grounding
The DO72 dissolved oxygen optical
sensor housing is made of stainless
steel with high corrosion resistance
(SUS 316 L).
However,electricpotentialdier-
ences between the DO72 and a tank
or other peripherals in the tank can
cause immediate corrosion through
electrolysis. Therefore, please
ensure to avoid electric potential
dierencesbetweenDO72andthe
surrounding environment.
We recommend always to connect
the DO72 to the protective ground
at the installation site. Assign the
device housing and cable shield to
protective ground.
Especially the length of the cable
caninuencethegroundconnec-
tion quality.
IftheDO72isinstalledinatting,
which is connected to the protective
ground, then the connection to the
ground will be established via the
PG13.5stainlesssteeltting(see
Fig. 11).
If the DO72 is installed in a tank
which is NOT connected to the
protectiveground(e.g.ttingmade
of plastic or glass), a ground con-
nection should be attached to the
DO72PG13.5tting(seeFig.12).
You can use a grounding clamp to
connect the DO72 directly to protec-
tive ground (see Fig. 13 for exam-
ple).
Fig. 11: DO72 grounding when installed
in a tank which is connected to protective
ground
Fig. 12: DO72 grounding when installed in
a tank which is NOT connected to protective
ground
Fig. 13: Example for a grounding clamp
that can be used for connecting an DO72 to
protective ground, when installed in a tank
without grounding.
PG13.5
Stainless steel thread
VP cable
shield
Green /
yellow
cable
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6. GENERAL CALIBRATION &
MAINTENANCE PROCEDURE
6.1 Pre-Calibration Input
In case the Oxygen Exchange Cap
screwed to the DO72 is connected for
thersttimeyoucanusecalibration
values of the factory pre-calibration.
Youcanndthesevaluesandsensor
constants on the Final Inspection Proto-
col (FIP, see Fig. 15) delivered with your
OEC. Use the values in the grey high-
lighted boxes of the FIP. For the detailed
setup instruction please refer to the
FLXA402 4-Wire Converter (IM12A01F01-
02EN).
6.2 DO72 two-point (Re)calibration
In case of requirement for recalibration
of DO72 use Two-point calibration in
oxygen free environment (e. g. nitrogen
5.0,1%sodiumsultesolution)anda
second calibration medium between
1 and 2 % oxygen. Best accuracy is
achieved if the calibration temperature
is about the same as the temperature
during the following measurements.
For calibrating sensor using FLXA402
analyzer please refer to section 4 of
FLXA402 user manual IM 12A01F05-
01EN.
Procedures how to prepare oxygen free
and medium environment in HUMID and
DRY calibration is described below:
• 1st Calibration Point HUMID: Oxy-
gen-free water
To prepare oxygen-free water dissolve 1
gofsodiumsulte(Na2SO3)in100mL
water.
Useasuitablevesselwithatightlytting
screw top and label it cal 0. Make sure
there is only little headspace in your ves-
sel. Due to a chemical reaction of oxygen
with the Na2SO3 the water becomes
oxygen-free.
Additionaloxygen,diusingfromair
into the water, is removed by surplus
Na2SO3.
Close the vessel with the screw top and
shake it for approximately one minute to
dissolve Na2SO3 and to ensure that the
water is oxygen-free. To prepare oxy-
gen-free water you also can use sodium
dithionite (Na2S2O4).
Fill the calibration solution cal 0 in the
vessel you have mounted the DO72 in.
Make sure the probe tip is covered com-
pletely with the liquid. To minimize the
response time, you can slightly stir the
solution.
Then follow the instructions in analyzer
calibration setting chapter respectively.
Afterrecordingtherstcalibrationpoint
removethecalibrationsolutioncal0,ll
the vessel with distilled water and stir
it for 1 minute. Repeat this procedure
at least 5 times to clean the OIM from
sodiumsulte.
For storing the calibration solution cal 0
keep the vessel closed after calibration
with a screw top to minimize oxygen
contamination. The shelf life of cal 0 is
about 24 hours provided that the vessel
has been closed with the screw top.
• 2nd Calibration Point HUMID: Air-satu-
rated water
Add 100 mL water to a suitable vessel
and label it cal 100. To obtain air-saturat-
ed water, blow air into the water using
an air-pump with a glass-frit (air stone),
creating a multitude of small air bub-
bles, while stirring the solution. After 20
minutes, switch of the air-pump and stir
the solution for another 10 minutes to
ensure that the water is not supersatu-
rated.

Fill the calibration solution cal 100 in
the vessel you have mounted the sen-
sor in. Make sure the sensor surface is
covered completely with the liquid. To
minimize the response time, slightly stir
the solution. Then follow the instructions
in analyzer calibration setting chapter
respectively.
Dry mode calibration – only for DO72-
T-120-AA-VP
• 1st Calibration Point DRY: Nitrogen-sat-
urated atmosphere
As an alternative you can use nitro-
gen-saturated atmosphere as calibration
standard cal 0. Use a commercially avail-
able test gas N2 (5.0).
Leadthegasintoavessellledwithdis-
tilled water before introducing it in the
calibrationchamberoraow-through
cell with installed DO72.
Then follow the instructions in analyzer
calibration setting chapter respectively.
• 2nd Calibration Point DRY: Water va-
por-saturated air
As an alternative you can use water-va-
por saturated air as calibration stan-
dard cal 100. Place wet cotton wool in a
suitable vessel and close the vessel with
attingscrewtoporlid.(Forinserting
the sensor into the vessel, you might
have to drill a hole in the lid.) Wait about
2 minutes to ensure that the air is water
vapor-saturated.
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6.3 Maintenance of the DO71 sensor
6.3.1 Routine inspection
Cleaning of Sensor (Oxygen exchange
cap) a visual inspection of the oxygen
exchange cap must be made whenever
the sensor is calibrated. Any dirt on the
oxygenendcapadverselyaectsyour
measurements.
If the dirt is spread over the oxygen
exchange cap, dip the oxygen exchange
cap into clean water and gently wipe
thedirtowithasoftclothorlint-free
paper.Ifthedirtdoesnotcomeo
easily, apply a neutral detergent to the
oxygen exchange cap so it can be easi-
er to remove the dirt. Wash the oxygen
exchange cap with clean water.
Before every calibration, check that the
oxygen exchange cap is not loose. If it is
loose, retighten it.
Cleaning procedure:
2% H2O2, acidic agents (HCL, H2SO4)
max. 4 – 5 % cleaning agents containing
CLO2 at room temperature.
6.3.2 Exchange of a used OEC
When replacing an OEC please make
sure to screw the new cap tightly (Fig.
14) to the probe body, so the black
O-ring is no longer visible. If the OEC is
not screwed on tightly (Fig. 15) the probe
body might get damaged by entering
liquid.
Fig. 15: O-ring visible - wrong OEC
installation
Fig. 14: Oxygen exchange cap installed
properly

Fig. 16: Example of Final inspection protocol
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IM12J06J02-00EN-P