ABB 7651 User manual

pH/ORP Electrode System
7600 Series
Instruction Manual
IM/7650_8

ABB
The Company
We are an established world force in the design and manufacture of instrumentation for industrial
process control, flow measurement, gas and liquid analysis and environmental applications.
As a part of ABB, a world leader in process automation technology, we offer customers
application expertise, service and support worldwide.
We are committed to teamwork, high quality manufacturing, advanced technology and unrivalled
service and support.
The quality, accuracy and performance of the Company’s products result from over 100 years
experience, combined with a continuous program of innovative design and development to
incorporate the latest technology.
The UKAS Calibration Laboratory No. 0255 is just one of the ten flow calibration plants operated
by the Company, and is indicative of our dedication to quality
and accuracy.
Information in this manual is intended only to assist our customers in the efficient operation of our equipment. Use of this manual
for any other purpose is specifically prohibited and its contents are not to be reproduced in full or part without prior approval of the
Technical Publications Department.
Health and Safety
To ensure that our products are safe and without risk to health, the following points must be noted:
1. The relevant sections of these instructions must be read carefully before proceeding.
2. Warning labels on containers and packages must be observed.
3. Installation, operation, maintenance and servicing must only be carried out by suitably trained personnel and in accordance with the
information given.
4. Normal safety precautions must be taken to avoid the possibility of an accident occurring when operating in conditions of high pressure and/
or temperature.
5. Chemicals must be stored away from heat, protected from temperature extremes and powders kept dry. Normal safe handling procedures
must be used.
6. When disposing of chemicals ensure that no two chemicals are mixed.
Safety advice concerning the use of the equipment described in this manual or any relevant hazard data sheets (where applicable) may be
obtained from the Company address on the back cover, together with servicing and spares information.
EN ISO 9001:2000
Cert. No. Q 05907
EN 29001 (ISO 9001)
Lenno, Italy – Cert. No. 9/90A
0255
Stonehouse, U.K.

1
CONTENTS
1 INTRODUCTION .................................................. 2
1.1 Schematic Diagrams ........................................ 2
2.1 Checking the Code Number............................. 3
2 PREPARATION .................................................... 3
2.2 Identifying the Electrode Type .......................... 4
2.3 Checking the Cable Specification .................... 6
2.4 Cleaning Options.............................................. 6
3.1 Siting ................................................................ 6
3.1.1 Operating Limits................................. 6
3MECHANICAL INSTALLATION........................... 6
3.1.2 Operating Pressure & Temperature ... 7
3.2 Installing the System ........................................ 7
3.2.1 Models 7651, 7652, 7660 and 7661 .. 7
3.2.2 Model 7652 ........................................ 8
3.2.3 Models 7654, 7655, 7656, 7664 and
7665 ................................................... 8
3.3 Fitting Electrodes ............................................. 8
3.3.1 Removing the Sensor Holder............. 8
3.3.2 Fitting the Reference Electrode ....... 10
3.3.3 Fitting the Measuring Electrode,
and the Temperature Compensator
1750-000 (if required) ...................... 10
3.3.4 Completion Tasks ............................ 11
3.4 Fitting the Reservoir – Models 7651, 7652,
7660 and 7661 ............................................ 12
4.1 Connection to AX, 4500 and 4600 Series
Transmitters – Fig. 4.1 and Table 4.1 .......... 13
4.2 Connection to Hazardous Area Systems ....... 13
4ELECTRICAL INSTALLATION .......................... 13
4.3 Cable Termination .......................................... 14
5CALIBRATING THE SYSTEM ........................... 15
5.1 General Calibration of electrodes.................. 15
5.2 Calibration of electrodes used in high purity
water applications........................................ 15
5.2.1 Monthly Calibration .......................... 15
5.2.2 3 Monthly Calibration ....................... 15
6.1 ‘O’ Ring Seals................................................. 16
6.2 Cleaning ......................................................... 16
6ROUTINE MAINTENANCE................................ 16
6.3 Checking the Electrolyte Level....................... 16
6.4 Replacing Electrodes ..................................... 16
6.4.1 Measuring Electrodes ...................... 16
6.4.2 Reference Electrodes.................................. 17
6.5 Recommended Maintenance of the
Company’s pH Systems .............................. 17
6.6 Fault Finding .................................................. 17
6.7 Loss of Sample .............................................. 18
7.1 Models 7651, 7652......................................... 18
7.2 Models 7654, 7655, 7656............................... 18
7.3 Model 7660 (stainless steel) .......................... 18
7.4 Reservoir Spares ........................................... 18
7SPARES ............................................................. 18
NOTES..................................................................... 19
Section Page Section Page

2
1INTRODUCTION
Mains in
Relays
A – Dip System
Current Output
Relays
Current Output
Mains in
B – In-Line System
0.000
Dual Cond.
0.000
uS/cm
uS/cm
0.000
Dual Cond.
0.000
uS/cm
uS/cm
This manual describes how to install and operate 7600 Series
industrial electrode systems. These systems are suitable for use
with a variety of measuring electrodes and pH meters operating
over a wide range of pressures and temperatures.
This manual describes:
•Model 7651 – polypropylene with optional pipe and flange
fittings.
•Model 7660 – stainless steel, in-line flow system.
•Model 7661 – PVDF, 1 inch flow system.
•Model 7652 – polypropylene, 2 inch in-line system with 2 inch
BS10 Table E flange fittings.
•Model 7654 – polypropylene, 1 metre (nominal) dip system.
•Model 7664 – PVDF, 1 metre (nominal) dip system.
•Model 7655 – polypropylene, 2 metre (nominal) dip system.
•Model 7665 – PVDF, 2 metre (nominal) dip system,
•Model 7656 – polypropylene, 3 metre (nominal) dip system.
Dip systems are for use in tanks, channels, etc.
All the above models are compatible with theAX, 4500 and 4600
Series pH transmitters. They may also be used with other
instruments such as 9140, 9170 and 9180 Series, but care must
be taken when connecting the temperature compensator – see
Section 4.1 for further details.
An alternative range of systems is available for use in hazardous
areas using approved intrinsically safe transmitters – see Section
4.2.
1.1 Schematic Diagrams – Fig. 1.1
Fig. 1.1 Schematics Diagrams

3
2PREPARATION
A – 7651 (Polypropylene) B – 7660 (Stainless Steel) C – 7652 (Polypropylene)
E – 7661 (PVDF)
7654 7664
D – Polypropylene 7655 PVDF
7665 7656
2.1 Checking the Code Number – Fig. 2.1
Fig. 2.1 System Types

4
…2 PREPARATION
Fitted to all systems.
Fitted to all systems except when
model 1740 ( Redox - ORP ) is used or if
manual temperature compensation is used.
*
1750-000 Temperature Compensator
ASEABROWNBOVERI
1740-000 Platinum Metal Electrode
ASEABROWNBOVERI
1741-000 Antimony Metal Electrode
ASEABROWNBOVERI
1721-000 & 1723-000 Cone-shaped Electrodes
ASEABROWNBOVERI
1722-000 Low Resistance Electrode
ASEABROWNBOVERI
1720-000 General Purpose Electrode
ASEABROWNBOVERI
1730-000 Reference Electrode
*
ASEABROWNBOVERI
2.2 Identifying the Electrode Type –
Fig. 2.2 and Table 2.1
A pH system is only as accurate as the electrodes used to make
the measurement. To satisfy a wide range of applications, and to
meet the demands of modern processes, the Company has
produced a range of electrodes to satisfy most requirements.
Reference Electrode (1730-000) fitted to all systems – used in
a sealed electrolyte or reservoir fed system, e.g. for applications
where the conductivity of the water is less than 30 µScm-1.
General Purpose Electrode (1720-000) – suitable for most
industrial applications. Operates from 0 to 14 pH, 0 to 100°C (32
to 212 °F) and must be used when the mechanical wiper is fitted.
Low Resistance Electrode (1722-000) – low resistance
membrane electrode for low temperature. For use in the water
industrywherethesample temperature dropsbelow10°C(50°F).
Operates from 0 to 10 pH, 0 to 70°C (32 to 158°F).
Note. For conductivities less than 30 µS cm-1 a
stainless steel system is recommended.
Cone Shaped Electrode (1721-000) – heavy duty electrode
designed specifically for ultrasonic cleaning. Operates from 0 to
14 pH, 0 to 100°C (32 to 212°F).
Low Temperature Cone Electrode (1723-000) – designed for
use with ultrasonic cleaner and especially where the sample is at
low conductivity/low temperature. Operates from 0 to 10 pH, 0 to
70°C (32 to 158°F).
Platinum Electrode for Redox (ORP), (1740-000) – platinum
electrodeenablesRedox(ORP)measurementstobemadeusing
any of the electrode systems.
Antimony pH Electrode (1741-000) – designed to work in
applications when hydrofluoric acid is present.
Temperature Compensator (1750-000) – three-wire PT100
temperature compensator required to ensure high accuracy. It is
compatible with older generations of Company instruments as
well as the current models.
Note. All of these electrodes are compatible with the
AX, 4500 and 4600 Series, 9140, 9170 and 9180
Series transmitters.
Fig. 2.2 Electrode Models

5
metsySedortcelExodeR/HpseireS0067 67 XX/0XX
lairetaMdnaepyTmetsyS smetsySenelyporpyloP htiwmetsyswolF
1
/ 2 snoitcennocssecorpni1dnani snoitcennocegnalfEelbaT01SBni2htiwmetsyswolF )ni93(m1–metyspiD )ni87(m2–metsyspiD )ni811(m3–metsyspiD 1525455565
metsySleetSsselniatS htiwmetsyswolF
3
/ 8 snoitcennocssecorpTPNni 06
smetsySFDVP htiwmetsyswolF
1
/ 2 snoitcennocssecorpni1dnani )ni93(m1–metyspiD )ni87(m2–metsyspiD 164656
epyTdnahtgneLelbaCnoitcennoC noitasnepmoCerutarepmeTcitamotuAhtiW elbacoN htgnel)tf01(m3 htgnel)tf61(m5 htgnel)tf33(m01 htgnel)tf66(m02 htgnellaicepS
0
1
2
3
4
S
)PRO(xodeRroF elbacoN htgnel)tf01(m3 htgnel)tf61(m5 htgnel)tf33(m01 htgnel)tf66(m02 htgnellaicepS
0
5
6
7
8
M
sepyTrosneS rosnesoN 0
edortcelessalgesopruplla000-0271 edortceleecnereferdradnats000-0371 rotasnepmocerutarepmet001TP000-0571 retawetsaw/ssecorplairtsudnirofdednemmoceR 1
edortcelessalgecnatsiserwol000-2271 edortceleecnereferdradnats000-0371* rotasnepmocerutarepmet001TP000-0571 sretawelbatoprofdednemmoceR 2
edortcelessalgdepahsenoc000-1271 edortceleecnereferdradnats000-0371 rotasnepmocerutarepmet001TP000-0571 snoitacilppalairtsudnirofrenaelccinosartluhtiwdesueboT 3
edortcelessalgdepahsenocecnatsiserwol000-3271 edortceleecnereferdradnats000-0371* rotasnepmocerutarepmet001TP000-0571 yrassecensigninaelccinosartluerehwsretawelbatoprofdednemmoceR 4
)PRO/xodeR(edortcelemunitalP000-0471 edortceleecnereferdradnats000-0371 snoitacilppaPRO/xodeRroF 5
)Hp(edortceleynomitnA000-1471 edortceleecnereferdradnats000-0371 nitneserpsidicAciroulfordyHerehwsnoitacilppaHprofdednemmoceR elpmaseht 6
edortcelessalgerutarepmethgih000-4271 edortceleecnereferdradnats000-0371 rotasnepmocerutarepmet001TP000-0571 snoitacilppaerutarepmethgihroF 7
2PREPARATION…
Note. For 1 metre and 2 metre
dipsystemsusingmechanicalor
ultrasonic cleaning, please refer
to separate specification sheet.
Note. For ultrasonic and
mechanical cleaning in Dip
systems,refer to the appropriate
manual for electrode details.
Note. For Intrinsically Safe
systems a maximum cable
length of 5 metres is permitted.
Note. For PVDF systems, only
options 1, 5 and 7 are available.
Table 2.1 Electrode Data

6
…2 PREPARATION 3MECHANICAL INSTALLATION
Red (Measuring Electrode)
Black (Reference Electrode)
A – Redox (ORP) and Manual
Temperature Compensated Systems
Blue
(Temp. Comp.)
B – pH Systems with Automatic
Temperature Compensation
Red
(Measuring Electrode)
Black
(Reference Electrode)
Used only on
4530/40 or 9180
(Cut back on other
instruments)
2.3 Checking the Cable Specification – Fig. 2.3
Check that cable length and termination is correct for the types
of electrode system being used – see Table 2.1 and Fig. 2.3.
2.4 Cleaning Options
The following methods of cleaning are available:
•Flow powered
•Ultrasonic
•Mechanical wiping
For assembly instructions refer to the appropriate instruction
manual (part no. IM/7600–CLN).
Caution.
•Ensure that the system cable is fed through the
electrode system cover (or dip tube) before the
cable is installed. To avoid the risk of damp or
corrosive air damaging the cable plugs, connect to
the electrodes as soon as possible.
•It is essential that fitted electrodes remain wet. If
there is loss of sample the fitted electrodes remain
serviceable while there is sample in the flowcell.
This may last for about a week depending on
prevailing climatic conditions. If it appears that
electrodes are drying out, periodically check and
top up the flowcell reservoir with clean water or
buffer solution.
3.1 Siting
3.1.1 Operating Limits
Model 7651 (Flow Type)see Fig. 3.1A for details
pH range: 0 to 14
Operating temperature range: 0 to 100°C (32 to 212°F)
Maximum operating temperature: 100°C at 2.1bar (212°F
at 30psi)
Maximum operating pressure
at 25°C (77°F): 10.6bar (150psi)
Model 7652 (In-line Type)see Fig. 3.1B for details
pH range: 0 to 14
Operating temperature range: 0 to 70°C (32 to 158°F)
Maximum operating temperature: 70°C (158°F), with no
pressure
Maximum operating pressure
at 25°C (77°F): 2.6bar (37psi)
Model 7654/5/6 (Dip Type)
pH range: 0 to 14
Operating temperature range: 0 to 80°C (32 to 176°F)
Maximum operating temperature: 80°C at 2.8bar (176°F
at 40psi)
Maximum operating pressure
at 25°C (77°F): 2.8bar (40psi)
Model 7660 (Flow Type)
pH range: 0 to 14
Operating temperature range: 0 to 100°C (32 to 212°F)
Maximum operating temperature: 100°C at 2.1bar (212°F
at 30psi)
Maximum operating pressure 0.3bar (5psi)
at 25°C (77°F):
Model 7661 (Flow Type)see Fig. 3.1C for details
pH range: 0 to 14 (0 to 11 at elevated
temperatures)
Operating temperature range: 0 to 110°C (32 to 230°F)
Maximum operating temperature: 110°C at 1.7bar (230°F
at 25psi)
Maximum operating pressure
at 25°C (77°F): 6.6bar (95psi)
Model 7664/5 (Dip Type)
pH range: 0 to 14
Operating temperature range: 0 to 110°C (32 to 230°F)
Fig. 2.3 Cable Termination – Electrode Connections

7
3MECHANICAL INSTALLATION…
3
/ 8 in NPT
Female
Thread
112 mm
65 mm
approx.
A–Type 7651
B–Type7660
174 mm (6
7
/
8
in)
235 mm (9
1
/
4
in approx)
44 mm (1
3
/
4
in)
1in BSPT
Female
Thread
Optional 1in. Nom.
Bore Pipe Flanges
Drilled to BS10
Table E
1
/
2
in BSPT or
NPT Female
Thread
Bosses M10 x 1.5
Internal Thread
Top Cover
274 mm (10
3
/
4
in)
Allow about 150 mm free space above the
top cover for access and removal of the cover.
44 mm (1
3
/
4
in)
Bosses M10 x 1.5
Internal Thread
250 mm (10 in approx)
110
100
90
80
70
60
50
40
30
20
10
020 40 60 80 100
Temperature T/C
Pressure/
(psi)
Pressure/ (bar)
7
6
5
4
3
2
1
02040
60 80 100
70
60
50
40
30
20
10
0
5
4
3
2
1
Temperature T/C
Pressure/
(psi)
Pressure/ (bar)
160
140
120
100
80
60
40
20
0
10
9
8
7
6
5
4
3
2
1
02040
60 80 100
Temperature T/C
Pressure/
(psi)
Pressure/ (bar)
B–Model7652
A– Models7660&7651
C–Model7661
Maximum operating temperature: 110°C (230°F) 3.1.2 Operating Pressure & Temperature – Fig. 3.1
3.2 Installing the System
3.2.1 Models 7651, 7652, 7660 and 7661 – Figs. 3.2 & 3.5
These may be mounted in any convenient position for the pipe
connections, using flexible or rigid piping. Allow sufficient space
above the system to enable the top cap to be unscrewed and
removed and for the entire electrode holder unit to be removed
from the flowcell for calibration.
TheflowcellonModels 7651,7660and 7661 isprovidedwithtwo
threaded fixing holes to support the electrode system from a
convenientverticalsurface– seeFigs.3.2and3.5.Also,aplastic-
coated bracket (7600 960) is supplied to enable the system to be
mountedonawall(whenitisnotpossible to fit bolts from the back
of the system). This bracket has an overall dimension of 164 x
60mm(61/2x23/8in)diameteronfixing centres 140x40mm (51/2x
19/16 in), symmetrically spaced, or with two bolts 12mm (1/2in)
diameter on fixing centres 140mm (51/2in) apart.
Fig. 3.1 Operating Temperatures and Pressures Fig. 3.2 Mounting, Types 7651 and 7660

8
Adjustable flanges to various standard drilling configurations are
also available to mount dip models close to a closed tank wall.
Note. Flanges available are very diverse. Please
consult the sales office for details.
…3 MECHANICAL INSTALLATION
1000 mm (39
3
/
8
in) or 2000 mm (79
3
/
4
in) 117 mm (4
5
/
8
in)
75 mm (3 in)
71.5 mm
Dia
(2
13
/
16
in)
35 mm
(1
3
/
8
in)
50.8 mm
(2 in)
25 mm
(1in)
44 mm
(1
3
/
4
in)
64 mm
(2
1
/
2
in)
79 mm
(31/8in)
102 mm
(4 in)
4 Holes 8.0mm Dia (
5
/
16
in)
WALL MOUNTING CLAMP
pt. no. 7604 440
One clamp for 1 metre models,
two clamps for 2 and 3 metre
models. Maximum immersion depth
203 mm (8 in)
93 mm (3
11
/
16
in)
52 mm (2
3
/
64
in)
George Fischer
Flange Adaptor
Pt No.735-810-108
Two Fixing Holes
M10 x 1.5 on
44 mm (1
3
/
4
in)
Centres
70 mm (2
3
/
4
in)
222 mm (8
3
/
4
in)
Allow about 150 mm (6 in)
free space above the top
cover for access and
removal of the cover.
2 in Flange BS 10 Table E
152 mm (6 in)
198.5 mm (713/16 in)
222 mm (83/4in)
Allow about 150 mm (6 in)
free space above the top
cover for access and
removal of the cover.
3.2.2 Model 7652 – Fig. 3.3
Thisisinstalledandheldinpositionbythe2 inBS10TableEfixing
flange only.
3.2.3 Models 7654, 7655, 7656, 7664 and 7665 – Fig. 3.4
These are dip systems installed in any convenient position over
the open tank or channel.
3.3 Fitting Electrodes –
Figs. 3.6, 3.7, 3.8, 3.9 and 3.10
Note.
•Ensure that the system cable is fed through the
electrode system cover or dip tube, as applicable,
before the cable is connected.
•Secure the cable in its permanent position,
ensuring sufficient free cable at both ends for
connection to the electrodes and to the meter.
Caution. To avoid the risk of damp or corrosive air
damaging the cable plugs, connect to the electrodes
as soon as possible.
3.3.1 Removing the Sensor Holder
Note. Reservoir-fed systems: only follow instructions
with respect to Flow/In-Line systems, then refer to
Section 3.4 to fit the reservoir assembly.
Fig. 3.3 Mounting, Type 7652
Fig. 3.4 Mounting, Types 7654, 7655, 7656,7664 and 7665
Fig. 3.5 Mounting, Type 7661