ABB ADS420 User manual

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ABB MEASUREMENT & ANALYTICS | OPERATING INSTRUCTION | OI/ADS420-EN REV. A
ADS420
Dissolved oxygen probe
Optical dissolved oxygen probe
Measurement made easy
Introduction
The ADS420 probe is a rugged, reliable instrument
designed to deliver accurate dissolved oxygen (DO)
data across a wide measurement range, using the
latest optical technology for DO measurement.
The probe is designed for use with ABB multi-input
transmitters, such as the AWT420 and AWT440,
which feature 'hot-plugging' capability.
Hot-plugging lets new or replacement sensors to be
connected without needing to power down the
transmitter.
When used in conjunction with the optional EZClean
compressed air supply unit (connected to an ABB
adaptor nozzle or T-piece), a schedule can be
configured to provide automatic in-situ cleaning of
the probe.
For more information
Further publications and publications for the
associated AWT420 and AWT440 transmitters are
available for free download from:
www.abb.com/measurement
or by scanning this code:
Search for or click on
Data Sheet ADS420
Optical dissolved oxygen probe DS/ADS420-EN
Commissioning Instruction
AWT420
Universal 4-wire, dual-input transmitter
CI/AWT420 - EN
Operating Instruction
AWT420
Universal 4-wire, dual-input transmitter
OI/AWT420-EN
Commissioning Instruction
AWT4 40
Multi-input transmitter
CI/AWT440-EN
Operating Instruction
AWT4 40
Multi-input transmitter
OI/AWT440-EN
CWA sensor accessories
Parts list PL/ANAINST/001-EN
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ADS420
dissolved oxygen probe

2ADS420 | DISSOLVED OXYGEN PROBE | OI/ADS420-EN REV. A
Contents
1 Health & Safety ..............................3
Document symbols .................................3
Safety precautions .................................3
Potential safety hazards ............................3
ADS420 probe – electrical........................3
Safety standards ...................................3
Product symbols ...................................3
Product recycling and disposal (Europe only) ........3
Information on RoHS Directive 2011/65/EU (RoHS II) .3
Cybersecurity ..................................... 4
2 System overview ............................5
ADS420 cable attached .............................5
ADS420 cable detached.............................5
3 Calibration ..................................6
Calibrate menu.................................... 6
1-Point calibration (water-saturated air) .............7
2-Point calibration (100 % and 0 % saturation) ...... 9
Abort calibration ..................................11
Calibration timings................................11
Stability period ................................ 11
Slow probe response ........................... 11
Calibration troubleshooting – slow sensor calibration
or no response to dissolved oxygen changes ........11
4 Maintenance ...............................12
Cleaning the sensor cap ...........................12
Cleaning the optical lens...........................12
Cleaning the probe body ...........................13
Diagnostic messages ..............................13
5 Spares .................................... 14
EZLink extension cables ...........................14
Cap spare parts ...................................14
Shroud spare parts ................................14

ADS420 | DISSOLVED OXYGEN PROBE | OI/ADS420-EN REV. A 3
1 Health & Safety
Document symbols
Symbols that appear in this document are explained below:
WARNING
This symbol in conjunction with the signal word 'WARNING'
indicates a potentially dangerous situation. Failure to
observe this safety information may result in death or
severe injury.
NOTICE
The signal word ‘NOTICE’ indicates potential material
damage.
‘Note’ indicates operator tips, particularly useful information or
important information about the product or its further uses.
‘Note’ does not indicate a dangerous or harmful situation.
Safety precautions
Be sure to read, understand and follow the instructions
contained within this manual before and during use of the
equipment. Failure to do so could result in bodily harm or
damage to the equipment.
WARNING
Installation, operation, maintenance and servicing must be
performed:
• by suitably trained personnel only
• in accordance with the information provided in this
manual
• in accordance with relevant local regulations
Potential safety hazards
ADS420 probe – electrical
The probe operates on 24 V DC supplied from the transmitter.
There are no hazardous voltages present.
Safety standards
This product has been designed to satisfy the requirements of
IEC61010-1:2010 3rd edition 'Safety Requirements for
Electrical Equipment for Measurement, Control and Laboratory
Use' and complies with US NEC 500, NIST and OSHA.
Product symbols
Symbols that may appear on this product are shown below:
Direct current supply only.
This symbol identifies a risk of chemical harm and
indicates that only individuals qualified and trained to
work with chemicals should handle chemicals or
perform maintenance on chemical delivery systems
associated with the equipment.
This symbol indicates the need for protective eye
wear.
This symbol indicates the need for protective hand
wear.
Recycle separately from general waste under the
WEEE directive.
Product recycling and disposal (Europe only)
ABB is committed to ensuring that the risk of any
environmental damage or pollution caused by any of
its products is minimized as far as possible. The
European Waste Electrical and Electronic Equipment
(WEEE) Directive that initially came into force on
August 13 2005 aims to reduce the waste arising from
electrical and electronic equipment; and improve the
environmental performance of all those involved in
the life cycle of electrical and electronic equipment. In
conformity with European local and national
regulations, electrical equipment marked with the
above symbol may not be disposed of in European
public disposal systems after 12 August 2005.
NOTICE
For return for recycling, please contact the equipment
manufacturer or supplier for instructions on how to return
end-of-life equipment for proper disposal.
Information on RoHS Directive 2011/65/EU
(RoHS II)
ABB, Process Automation, Measurement & Analytics,
UK, fully supports the objectives of the RoHS II
directive. All in-scope products placed on the market
by PAMA UK on and following the 22nd of July 2017, will
be compliant to the RoHS directive, 2011/65/EU.

4ADS420 | DISSOLVED OXYGEN PROBE | OI/ADS420-EN REV. A
…1 Health & Safety
Cybersecurity
This product is designed to be connected to and to
communicate information and data via a network interface. It is
operator’s sole responsibility to provide and continuously
ensure a secure connection between the product and your
network or any other network (as the case may be). Operator
shall establish and maintain any appropriate measures (such as
but not limited to the installation of firewalls, application of
authentication measures, encryption of data, installation of
anti-virus programs, etc.) to protect the product, the network,
its system and the interface against any kind of security
breaches, unauthorized access, interference, intrusion, leakage
and/or theft of data or information. ABB and its affiliates are
not liable for damages and/or losses related to such security
breaches, any unauthorized access, interference, intrusion,
leakage and/or theft of data or information.

ADS420 | DISSOLVED OXYGEN PROBE | OI/ADS420-EN REV. A 5
2 System overview
ADS420 cable attached
ADS420 probe components (cable attached) are shown in
Figure 1:
ADS430xxxxxx
Figure 1 ADS420 probe components (cable attached)
Table 1 Probe components (cable attached)
Part Description
AEZLink™digital sensor connector
BShroud
CSensor cap (supplied unfitted in sealed factory-supplied container)
Note. The sensor cap serial number is programmed on the memory
chip inside the sensor cap.
DProbe body (including temperature sensor)
E10 m (39.3 ft) fixed cable
ADS420 cable detached
ADS420 probe components (cable detached) are shown in
Figure 2:
Figure 2 ADS420 probe components (cable detached)
Table 2 Probe components (cable detached)
Part Description
AEZLink digital sensor connector
BShroud
CSensor cap (supplied unfitted in sealed factory-supplied container)
Note. The sensor cap serial number is programmed on the memory
chip inside the sensor cap.
DProbe body (including temperature sensor)

6ADS420 | DISSOLVED OXYGEN PROBE | OI/ADS420-EN REV. A
3 Calibration
This section describes how to calibrate the probe and involves measuring the probe’s sensitivity to oxygen by exposing the probe
to water-saturated air.
Calibrations are initiated via the Cal prompt displayed on Operator pages or via the Calibrate and Advanced menu
items on the Access Level page – refer to transmitter Operating instructions OI/AWT420-EN for all transmitter menu options.
Note.
• Do not perform a calibration until the probe and transmitter are installed and ready for operation.
• Before removing the probe for calibration purposes, set the currents outputs and alarms to Hold (enabled via the Operator
Menu/Manual Hold function).
• After calibration and probe replacement, reset the currents outputs and alarms – see Calibrate menu below.
Calibrate menu
Calibrate
Menu
Exit Select
Used to calibrate the probe.
Access to the Calibrate menu is permitted via the Calibrate and Advanced levels only.
Note. During calibration, current outputs and alarms are set to Hold automatically if
Hold Outputs is enabled (see below).
Menu Comment Default
S1 (to 4) :DO Select the optical dissolved oxygen probe to calibrate.
Pro be Calibration
Calibration Type
1-Point Cal Select to perform a 1-point calibration in water-saturated air (100% saturation):
2-Point Cal Select to perform a 100 % saturation calibration in water-saturated air and a 0 %
saturation calibration in an oxygen-depleted solution, e.g. sodium sulphite
(Na2SO3).
Hold Outputs Enable/disable the Hold Outputs function. If enabled, the current outputs and
alarm functions are held during calibrations.
Enabled

ADS420 | DISSOLVED OXYGEN PROBE | OI/ADS420-EN REV. A 7
1-Point calibration (water-saturated air)
1 Using a customer-supplied calibration pot, place a wetted
sponge at the bottom of the container.
2 Ensure the probe and sensing element are completely dry. If
necessary use a paper towel to remove any water or debris
from the probe or sensing element.
3 Slide probe into calibration chamber until the sensing
element is approximately 25 mm (1 in) above water-saturated
sponge.
4 Allow 5 to 10 minutes for temperature stabilization prior to
continuing the calibration procedure.
NOTICE
• Do not leave the probe in the calibration chamber for
more than 30 minutes – this can allow condensation to
form on the surface of the sensing element, producing
false low readings after calibration.
• If condensation occurs, remove the probe, thoroughly dry
the sensing element, probe and thermistor before
performing the calibration procedure.
• Ensure the calibrations are perfomed in a vented but
enclosed chamber, to prevent pressure building up in the
container.
• Minimize ambient airflow across the sensor head during
the calibration.
5 At the transmitter perform a 1-point calibration from an
Operator page as follows:
CAL
2014–08–20
10:34:52
7.62
25 °C
ppm
Dissolved Oxygen
6 Press the key (below the Cal prompt).
The Calibrate page is displayed:
Calibrate
Menu
Exit Select
7 Press the key (below the Select prompt).
The Calibrate page is displayed with all available sensors
shown:
Calibrate
S1: DO
Back Select
8 Use the / keys to select the probe to be calibrated and
press the key (below the Select prompt).
The Calibration Type page is displayed:
S1: DO
Next Edit
Calibration Ty pe
1-Point Cal

8ADS420 | DISSOLVED OXYGEN PROBE | OI/ADS420-EN REV. A
…3 Calibration
…1-Point calibration (water-saturated air)
9 If 1-Point Cal is displayed, go to step 12.
If 1-Point Cal is not displayed, press the key
(below the Edit prompt).
The Calibration Type selection page is displayed:
Calibration Type
1-Point Cal
2-Point Cal
Cancel OK
10 Use the / keys to select 1-Point Cal and press the
key (below the OK prompt).
The Calibration Type page is displayed:
S1: DO
Next Edit
Calibration Ty pe
1-Point Cal
11 Press the key below the Next prompt).
The Calibrate/Start Span Cal? page is displayed:
Calibrate
Start Span Cal?
Place in 100 % Sat
Abort Continue
12 Press the key (below the Continue prompt).
The Calibrate page is displayed:
Calibrate
PV 98.26 %
Tmp 25.22 °C
Setting-Please Wait
Abort
13 When span calibration is complete, a results page is
displayed:
Calibrate
PV 98.98 %
Tmp 24.90 °C
Offset 0.045
Slope 1.054
Exit
In the event of a calibration failure, the message Calibration
Failed is displayed with an indication of the reason for
failure, for example ‘Result Out Of Bounds’.
14 Press the key (below the Exit prompt).
The Calibrate page is displayed:
Calibrate
S1: DO
Back Select
15 Press the key (below the Back prompt).
The Calibrate page is displayed:
Calibrate
Menu
Exit Select
16 Press the key (below the Exit prompt) to return to the
Operator page.

ADS420 | DISSOLVED OXYGEN PROBE | OI/ADS420-EN REV. A 9
2-Point calibration (100 % and 0 % saturation)
Note. This calibration procedure requires 60 mL (2.0 fl oz [US])
of fresh sodium sulphite solution.
1 Using a customer-supplied calibration pot, place a wetted
sponge at the bottom of the container.
2 Ensure the probe and sensing element are completely dry. If
necessary use a paper towel to remove any water or debris
from the probe or sensing element.
3 Slide probe into calibration chamber until the sensing
element is approximately 25 mm (1 in) above water-saturated
sponge.
4 Allow 5 to 10 minutes for temperature stabilization prior to
continuing the calibration procedure.
NOTICE
• Do not leave the probe in the calibration chamber for
more than 30 minutes – this can allow condensation to
form on the surface of the sensing element, producing
false low readings after calibration.
• If condensation occurs, remove the probe, thoroughly dry
the sensing element, probe and thermistor before
performing the calibration procedure.
• Ensure the calibrations are perfomed in a vented but
enclosed chamber, to prevent pressure building up in the
container.
• Minimize ambient airflow across the sensor head during
the calibration.
5 At the transmitter perform a 2-point calibration from an
Operator page as follows:
CAL
2014–08–20
10:34:52
7.62
25 °C
ppm
Dissolved Oxygen
6 Press the key (below the Cal prompt).
The Calibrate page is displayed:
Calibrate
Menu
Exit Select
7 Press the key (below the Select prompt).
The Calibrate page is displayed with all available sensors
shown:
Calibrate
S1: DO
Back Select

10 ADS420 | DISSOLVED OXYGEN PROBE | OI/ADS420-EN REV. A
…3 Calibration
…2-Point calibration (100 % and 0 % saturation)
8 Use the / keys to select the probe to be calibrated and
press the key (below the Select prompt).
The Calibration Type page is displayed:
S1: DO
Next Edit
Calibration Ty pe
2-Point Cal
9 If 2-Point Cal is displayed, go to step 11.
If 2-Point Cal is not displayed, press the key (below the
Edit prompt).
The Calibration Type selection page is displayed:
Calibration Type
1-Point Cal
2-Point Cal
Cancel OK
10 Use the / keys to select 2-Point Cal and press the
key (below the OK prompt).
The Calibration Type page is displayed:
S1: DO
Next Edit
Calibration Ty pe
2-Point Cal
11 Press the key below the Next prompt).
The Calibrate/Start Span Cal? page is displayed:
Calibrate
Start Span Cal ?
Place in 100 % Sat
Abort Continue
12 Press the key (below the Continue prompt).
The Calibrate page is displayed:
Calibrate
PV 98.26 %
Tmp 25.22 °C
Setting-Please Wait
Abort
13 When span calibration is complete, the Calibrate/Start Zero
Cal? page is displayed:
Calibrate
Start Zero Cal?
Place in 0 % Sat
Abort Continue
14 Remove the sponge wafer from the calibration pot.
15 Fill calibration chamber with fresh sodium sulphite solution,
leaving at least 13 mm (0.5 in) between the surface of the
sensing element and the bottom of the chamber.
16 Allow 5 to 10 minutes for temperature stabilization prior to
continuing the calibration procedure.
17 Press the key (below the Continue prompt).
The Calibrate page is displayed:
Calibrate
PV 2.31 %
Tmp 25.32 °C
Setting-Please Wait
Abort

ADS420 | DISSOLVED OXYGEN PROBE | OI/ADS420-EN REV. A 11
18 When zero calibration is complete, a results page is
displayed:
Calibrate
PV 2.31 %
Tmp 25.40 °C
Offset 0.041
Slope 0.954
Exit
19 Press the key (below the Exit prompt).
The Calibrate page is displayed:
Calibrate
S1: DO
Back Select
20 Press the key (below the Back prompt).
The Calibrate page is displayed:
Calibrate
Menu
Exit Select
21 Press the key (below the Exit prompt) to return to the
Operator page.
22 Once the calibration is complete, remove the sensor from
the chamber and rinse thoroughly to remove all of the
sodium sulphite.
Abort calibration
A calibration is aborted by pressing the key below the Abort
prompt displayed on the Calibrate pages (refer to the
transmitter Operating Instructions OI/AWT420-EN).
The Calibration Log displays the message Cal Aborted – refer
to OI/AWT420-EN for Calibration Log entries.
Calibration timings
Stability period
The temperature and concentration readings are monitored for
up to 10 minutes until a stable reading is achieved. When
stability is achieved, the calibration (slope and offset) values
are determined.
Slow probe response
If the output from the probe does not stabilize during the
Stability Period the calibration is not accepted and a Cal Failed
diagnostic is displayed, the Calibration Log is updated with a
Cal Failed message.
Calibration troubleshooting – slow sensor
calibration or no response to dissolved
oxygen changes
1 Check probe configuration/recalibrate probe.
If the fault persists:
2 Clean the sensor cap and lens – refer to Maintenance on
page 12.
If the fault persists:
3 Replace the sensor cap – refer to Spares on page 14.
If the fault persists:
4 Replace the probe.

12 ADS420 | DISSOLVED OXYGEN PROBE | OI/ADS420-EN REV. A
4 Maintenance
Cleaning the sensor cap
1 Remove the sensor from the process.
Referring to Figure 3:
2 Unscrew shroud Afrom probe body B.
3 Rinse sensor cap Cwith clean water from a spray bottle.
4 Gently wipe sensor cap Cwith a soft-bristled brush or, if
biofouling is present, a soft cloth.
If necessary, use a grease remover to remove grease.
5 Refit shroud Aby screwing it onto probe body B.
C
A
B
Figure 3 Cleaning the sensor cap
Cleaning the optical lens
1 Isolate the transmitter and remove the probe from the
process.
Referring to Figure 4:
2 Unscrew shroud Afrom probe body B.
3 Grip sensor cap Cbetween your thumb and forefinger and
carefully slide it off probe sensor D.
NOTICE
• Do not touch the end of the sensor cap C.
• Do not allow moisture or atmospheric humidity inside
sensor cap C.
• Do not wet the lens area Ewith water or any solution.
Use only the supplied lens cloth for cleaning.
4 Gently wipe optical lens Ewith a lens cloth (not supplied).
5 Refit shroud Aby screwing it securely onto probe body B.
C
B
A
D
E
Figure 4 Cleaning the optical lens

ADS420 | DISSOLVED OXYGEN PROBE | OI/ADS420-EN REV. A 13
Cleaning the probe body
Note. Make sure that the shroud Ais installed tightly before
you start to clean the probe body.
1 Isolate the transmitter and remove the probe from the
process.
Referring to Figure 5:
2 Gently scrub the shroud Aand the probe body Bwith a
soft-bristled brush or a nylon dish scrubber.
If it is necessary, use a grease remover to remove grease or
other matter from the body, or soak in vinegar and deionized
water to remove mineral deposits or extensive fouling.
Figure 5 Cleaning the probe body
Diagnostic messages
The table below shows sensor-specific icon types, diagnostic
messages and possible causes/suggested remedial action.
Note.
• The diagnostic icons in the following tables conform to
NAMUR 107.
• For transmitter-specific diagnostics messages, refer to
OI/AWT420-EN.
Diagnostic Icon NAMUR Status
Out of specification
Maintenance required
Check function
Icon Message Possible cause/suggested action
Cap Expired
(S1, S2, S3, S4)
The optical DO sensor cap has reached or
exceeded its expiry date. The sensor cap may
continue operating but its accuracy will degrade
and cannot be guaranteed to meet specification.
Replace Cap The optical DO sensor cap will reach
expiry date in 4 weeks or less.
Replace sensor cap.
Cap Removed The sensor cap has been removed.
The reading will drop to zero.
Ensure sensor cap is fitted onto the probe tip.

14 ADS420 | DISSOLVED OXYGEN PROBE | OI/ADS420-EN REV. A
5 Spares
EZLink extension cables
Part number Description
AWT4 00 9010
AWT4 00 9050
AWT4009100
AWT4 00 9150
AWT4009250
AWT4009500
1 m (3.3 ft)
5 m (16.4 ft)
10 m (32.8 ft)
15 m (49.2 ft)
25 m (82.0 ft)
50 m (164.0 ft)
Sensor cap spare parts
Part number Description
3KXA494400L0019 Sensor cap replacement kit
Shroud spare parts
Part number Description
3KXA494400L0020 Shroud replacement kit

ADS420 | DISSOLVED OXYGEN PROBE | OI/ADS420-EN REV. A 15
Acknowledgements
• EZLink is a trademark of ABB Limited.

OI/ADS420-EN Rev. A 04.2022
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ABB Measurement & Analytics
For your local ABB contact, visit:
www.abb.com/contacts
For more product information, visit:
www.abb.com/measurement
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We reserve the right to make technical changes or modify the contents of this document
without prior notice. With regard to purchase orders, the agreed particulars shall prevail.
ABB does not accept any responsibility whatsoever for potential errors or possible lack of
information in this document.
We reserve all rights in this document and in the subject matter and illustrations contained
therein. Any reproduction, disclosure to third parties or utilization of its contents – in
whole or in parts – is forbidden without prior written consent of ABB.
© ABB 2022
All rights reserved. 3KXA494400R4201