ABB Nitrate 8236 User manual

ISE Nitrate Monitor
8236
Instruction Manual
IM/8236_8

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. Chemicalsmustbestoredawayfromheat,protectedfromtemperatureextremesandpowderskeptdry.Normalsafehandlingprocedures
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.
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.
EN ISO 9001:2000
Cert. No. Q 05907
R
E
G
I
S
T
E
R
E
D
EN 29001 (ISO 9001)
Lenno, Italy – Cert. No. 9/90A
0255
Stonehouse, U.K.
Warning – Refer to the manual for instructions
Caution – Risk of electric shock
Protective earth (ground) terminal
Earth (ground) terminal
Direct current supply only
Alternating current supply only
Both direct and alternating current supply
The equipment is protected
through double insulation
Electrical Safety
This equipment complies with the requirements of CEI/IEC 61010-1:1993 "Safety requirements for electrical equipment for
measurement, control, and laboratory use". If the instrument is used in a manner NOT specified by the Company, the protection
provided by the instrument may be impaired.
Symbols
One or more of the following symbols may appear on the equipment labelling:
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.

1
CONTENTS
Section Page Section Page
1 INTRODUCTION ..............................................................2
1.1 Description...............................................................2
1.2 Training ....................................................................2
1.3 Location and Function of Main Components ...........2
2 INSTALLATION................................................................3
2.1 Accessories .............................................................3
2.2 Location ...................................................................3
2.3 Mounting ..................................................................3
2.4 Sampling Requirement ............................................3
2.5 Sample Connections................................................3
2.6 Connections, General ..............................................4
2.7 External Electrical Connections ...............................5
2.8 Relay Contact Protection and Interference
Suppression ..........................................................6
3SETTING UP ....................................................................7
4LIQUID HANDLING SECTION ........................................8
4.1 Principle of Operation ..............................................8
4.2 General Operation ...................................................9
5ELECTRONICS SECTION...............................................9
5.1 Electronic Layout .....................................................9
5.2 User Junction Box....................................................9
5.3 Microprocessor Unit.................................................9
5.4 Front Panel Controls..............................................10
5.5 Displays .................................................................10
5.6 L.E.D. Indication ....................................................10
6 PROGRAMMING ........................................................... 11
6.1 Normal Operation ..................................................12
6.2 Programming Pages ..............................................12
6.2.1 Operating Page 1 ....................................13
6.2.2 Operating Page 2 ....................................14
6.2.3 Security Code Page ................................15
6.2.4 Set Up Input Page ...................................16
6.2.5 Current Output Page ...............................17
6.2.6 Set Up Alarms Page ................................20
6.2.7 Set Up Clock Page ..................................22
6.2.8 Calibration User Code Page....................24
6.2.9 Set Up Temperature Control Page ..........25
6.2.10 Electrical Calibration..............................25
6.2.11 Electrical Calibration Page.....................26
7 CALIBRATION ...............................................................29
7.1 Calibration Sequence ............................................29
8 MAINTENANCE .............................................................30
8.1 Chemistry...............................................................30
8.1.1 Reagent Solution .....................................30
8.1.2 Standard Solutions ..................................30
8.1.3 Reference Salt Bridge Solution ...............30
8.2 Scheduled Servicing ..............................................30
8.2.1 Regular Visual Checks ............................30
8.2.2 Four Weekly ............................................30
8.2.3 Four Monthly ...........................................31
8.2.4 Twelve Monthly........................................31
8.2.5 Cleaning Sample Pipework .....................31
8.2.6 Consumables Spares Kit .........................32
8.2.7 Fitting the Electrode ................................32
8.2.8 Peristaltic Pump ......................................33
8.2.9 Replacement of Plumbing Tubing ...........33
8.3 Shutdown Procedure .............................................34
8.3.1 Short Term ...............................................34
8.3.2 Long Term................................................34
8.4 Unscheduled Servicing ..........................................34
8.4.1 Malfunction of the Monitor .......................34
8.4.2 Monitor Diagnostic Information................35
8.5 Refurbishing the Electrode ....................................35
8.6 Microprocessor Unit Error Messages ....................36
9 SPECIFICATION ............................................................37
10 SPARES LIST ..............................................................38
APPENDIX A – REPLACING SOFTWARE EPROM...........40
A.1 Access the Transmitter Unit ..................................40
A.2 Access the PCB ....................................................40
A.3 Removing the PCB................................................41
A.4 Changing the EPROM...........................................41
A.5 Completing the Procedure.....................................41
NOTES.................................................................................42

2
1.1 Description
The Model 8236 Nitrate Monitor is a microprocessor based
analyser using an ABB nitrate ion-selective probe. This
equipment is used for environmental water monitoring.
1.2 Training
Due to the specialised nature of the above instrument, it is
recommended that, where the end users personnel have had no
previous experience of maintaining this equipment, training be
provided by this Company.
Such training is available via the local Company in the UK, or
OverseasAgent elsewhere and may be carried out either on the
users premises or at the factory.
1.3 Location and Function of Main Components –
Fig. 1.1
Monitoring of any sample by ion-selective electrodes usually
requires certain conditioning to be performed on the sample to
allow accurate, trouble-free measurement. Such conditioning
involves regulating flow, controlling temperature and adjusting
chemical composition prior to presentation of the sample to the
point of measurement. This monitor carries out these
adjustments for each parameter in simple and easily understood
steps. The sample is presented from the user's pipework to a
constant head unit and any excess is allowed to overflow. This
allows sample, under controlled pressure conditions, to be
presented to a multi-channel peristaltic pump which proportions
sample and reagent solutions through the monitor to the mixing
point. The resulting combined solution is then temperature
controlled to remove the effects of sample and ambient
temperaturevariations.Theconditionedsolutionisthendelivered
to the flowcell, under constantly flowing conditions, where the ion
measurement takes place. This measurement is carried out
using an ion-selective sensing electrode.
The sensor generates a millivolt output which is proportional to
the ion concentration. This output is processed by the
microprocessor-based electronics section to calculate the actual
sample concentration.
To maintain optimum measurement accuracy it is necessary to
introduce standard solutions of known concentration for
calibration purposes. The monitor utilises solenoid valves to
introduce these standard solutions automatically, at
predeterminedintervals,underthecontrol of the microprocessor.
The electronics section consists of the main Microprocessor Unit
situated at the top left and a User Junction Box at the top right
behind the hinged case.
Fig. 1.1 Location of Instrument Components
1INTRODUCTION
Nitrate 8236
Calibration
Solution
Containers
Constant Head Unit
(behind case)
with Sample Inlet and
Drain Connections
Peristaltic
Pump
Case Lock
Heated
Sensor
Flow Cell
ISE,
Reference Electrode and
Temperature Sensor
Cable Entry Glands
Case Lock
Microprocessor
Unit
Hinged Case
Solenoid Valves
(behind case)
User Junction Box
(behind case)
Hinged Door
Push-to-Release
Latch

3
2.1 Accessories
1 x reagent bottle 1 x nitrate refurbishing kit
4 x calibration bottles 1 x double junction
1 x nitrate inner electrode reference electrode
1 x spares kit
2.2 Location
Themonitorshouldbeinstalledinaclean,dry,wellventilatedand
vibration-free location giving easy access, and where short
sample lines can be used. Rooms containing corrosive gases or
vapours (e.g., chlorination equipment or chlorine gas cylinders)
should be avoided. It is also advisable to have adjacent drains
neargroundlevel,sothatthewasteoutletfromthemonitorcanbe
as short as possible, together with maximum fall. Power supplies
shouldalsobe adjacent.Ambienttemperature:within therange5
to 40°C.
2.3 Mounting – Fig. 2.1
The monitor has a moulded plastic case, mounted onto a flat
metal panel. To provide access, the case is hinged on the left
hand side and has two lockable catches on the right hand to hold
the case in position in normal operation.
One keyhole slot is provided at the top of the flat panel to provide
easy mounting on a wall or framework. Two further fixing holes
areprovided atthe bottomoftheflatpanel.Allholes aredesigned
to take 8 mm bolts or studs.
Mains and signal cables are connected through cable glands in
theUser JunctionBoxon therighthandsidewith theexceptionof
the optional serial interface which connects directly into the
Microprocessor Unit. Sample and drain pipework are brought in
through the bottom of the case.
2.4 Sampling Requirement
In addition to being as close as possible to the monitor, the
sampling point must provide a thoroughly mixed representative
sample. The sample must also conform to the following
conditions:
a) Sample flow rates must be between 5 ml min–1 and
1250 ml min–1.
b) Sample temperature should be within 20 °C of the ambient
temperature and within the range 0 to 40°C.
c) Particles must be less than 10 mg l–1 and the size must not
exceed 60 µm. Above these levels it is essential that the filter
supplied is fitted in both the sample and emergency inlets.
2.5 Sample Connections – Fig. 2.2 (overpage)
The inlet and outlet pipe connections are both located at the
bottom of the case.A6 mm (1/4") hose adaptor is provided for the
sampleinletanda9 mm(3/8")hoseconnectionfor the drains. It is
recommended that the pipes used should be of inert material,
e.g., silicone rubber or p.v.c. The inlet pipe must incorporate a
shut-off valve at its upstream end, while the drain outlet pipes
should be short, venting to atmosphere as soon as possible.
2INSTALLATION
Fig. 2.1 Overall Dimensions and Mounting Details
Junction
Box
60 Top of Case
30
Sample Inlet
& Drain
Tubes
110mm minimum clearance
required for accessto locks
Fixing Centres
Moulded Case
Shown in
Open Position
780
Fixing
Centres
278
482
220
Cable
Entry
Point
188
890
Open
Position
95Max.
angle of
opening 542
235
550
Closed
Position
8mm Keyhole
Slot
8mm Fixing
Holes Top View
Edge of
Case All dimensions in mm

4
…2 INSTALLATION
2.6 Connections, General
Warnings.
•Adisconnecting device such as a switch or circuit breaker conforming to local safety standards must be fitted to the final
installation.Itmustbefittedincloseproximitytotheinstrumentwithineasyreachoftheoperatorandmustbemarkedclearly
as the disconnection device for the instrument.
•Althoughcertaininstrumentsarefittedwithinternalfuseprotection,asuitablyratedexternalprotectiondevice,e.g.a3Afuse
or miniature circuit breaker (m.c.b.), must also be fitted by the installer.
•Remove all power from supply, relay and any powered control circuits and high common mode voltages before accessing
or making any connections.
•The power supply earth (ground) must be connected to ensure safety to personnel, reduction of the effects of RFI
interference and correct operation of the power supply interference filter.
•The power supply earth (ground) must be connected to the earth (ground) stud on the junction box case – see Fig. 2.3.
•Use cable appropriate for the load currents. The terminals accept cables up to 14AWG (2.5mm2).
•The instrument conforms to Mains Power Input Insulation Category III.All other inputs and outputs conform to Category II.
•All connections to secondary circuits must have basic insulation.
•After installation, there must be no access to live parts, e.g. terminals.
•Terminals for external circuits are for use only with equipment with no accessible live parts.
•The relay contacts are voltage-free and must be appropriately connected in series with the power supply and the alarm/
control device which they are to actuate. Ensure that the contact rating is not exceeded. Refer also to Section 2.8 for relay
contact protection details when the relays are to be used for switching loads.
•Do not exceed the maximum load specification for the selected analog output range.
The analog output is isolated, therefore the –ve terminal must be connected to earth (ground) if connecting to the isolated
input of another device.
•If the instrument is used in a manner not specified by the Company, the protection provided by the equipment may be
impaired.
•All equipment connected to the instrument's terminals must comply with local safety standards (IEC 60950, EN61010-1).
Notes.
•Anearthing(grounding)–studterminalisfittedtothejunctionboxcaseforbus-barearth(ground)connection–seeFig.2.3.
•Always route signal output and mains-carrying/relay cables separately, ideally in earthed (grounded) metal conduit. Use
twisted pair output leads or screened cable with the screen connected to the case earth (ground) stud.
Ensure that the cables enter the analyzer through the glands nearest the appropriate screw terminals and are short and
direct. Do not tuck excess cable into the terminal compartment.
•Ensure that the IP65 rating is not compromised when using cable glands, conduit fittings and blanking plugs/bungs (M20
holes). The M20 glands accept cable of between 5 and 9mm (0.2 and 0.35 in.) diameter.

5
2.7 External Electrical Connections – Fig. 2.3
The external electrical connections are to be found in the User
Junction Box with the exception of the optional serial interface
which is connected directly into the Microprocessor Unit. The
cablesarepassedthroughthecableglandsontherighthandside
of the junction box which are adjacent to the internal electrical
terminals.
Caution. Slacken the terminal screws fully before making
connections.
2INSTALLATION…
Fig. 2.2 Suggested Layout
The connections are as follows:
a) Mains input 115 V or 240 V. The mains voltage is selected by
means of the voltage selector – see Fig. 2.3.
b) Currentoutputs1and 2– twoindependent currentoutputs for
external recording or control. One output is supplied as
standard, the second is supplied as an optional extra – see
Fig. 2.4 for details of current output range.
Information. Because the current output is isolated, the
negative terminal must be connected to earth (ground) if
connecting to the isolated input of another device.
c) Relay 1 and 2 – two concentration alarms.
d) Relay 3–calibrationmodeindication.Thisindicateswhenthe
instrument is off line during a calibration.
e) Relay 4 – instrument 'OUT OF SERVICE' indication. This
indicates that the monitor readings are suspect and it is in
need of attention.
f) Relay 5 – 'OUT OF SAMPLE' – indication of loss of sample.
g) Optionalserialinterface–connected intothe Microprocessor
Unit. See supplementary instruction manual for details.
Sample Inlet Pipe
(6 mm i.d.) Drain Tundish
Contaminated Drain pipe
(9 mm i.d.)
Tube wall fixing clips
N.B. Sample, drain and overflow pipework
in flexible silicone rubber or PVC
150 mm
(approx)
Monitor Case
Case Hinge Line Push-on hose connectors
Constant-head unit
250 mm (approximate) length
tubing
to allow the case
to open through 90
Overflow
Drain
Note. It is essential that all
sample pipework to the
monitor is kept as short as
possible to reduce the
effects on the sample due to
the presense of algæ which
can build up. This problem is
particularly acute in the
pipework between the filter
and the monitor because of
the small sample flow. Small
bore tubing is essential, e.g.
6 mm i.d.

6
L
N
N/C
C
N/O
N/C
C
N/O
N/C
C
N/O
N/C
C
N/O
N/C
C
N/O
+
-
+
-
RELAY
1
RELAY
2
CAL
OUT
OF
SERVICE
OUT
OF
SAMPLE
O/P 1
O/P 2
MAINS
INPUT
STD1 STD2
HEATER
230V
MainsVoltage Selector
110V to120V 220V to 240V
User
Cable
Entry
Glands
External
User
Connection
Terminals
Interconnection Cable from/to
Microprocessor Unit and Instrument
Components (wet section)
Internal
Interconnection
Cable Terminals
Solenoid Valves
and Heater
Indicators
Relay
Board
Mains
Transformer
Mains Fuse –
1A, 250V AC (T)
Cable Gland
MAINS
MAINS
F1 250V 1A (T)
PUMP
Mains 'ON'
Indicator
Mains
ON / OFF
Switch
Pump
ON / OFF
Switch
OFF
ON
OFF
ON
230V Position
220V min. to 240V max. AC
50/60Hz
115V Position
110V min. to 120V max. AC
50/60Hz
F2 5A 250V AC (F)
F3 0.5A 250V AC (T)
as shown in Fig. 2.5A. If the instrument malfunctions the value of
the RC network is too low for suppression and an alternative
value must be used. If the correct RC suppressor unit cannot be
obtained, contact the manufacturer of the switched device for
details of the RC unit required.
For d.c. applications fit a diode as shown in Fig. 2.5B. For
general applications use an alternative IN5406 type (600 V peak
inverse voltage at 3 A – part no. B7363).
Note. For reliable switching the minimum voltage must be
greater than 12 V and the minimum current greater than
100 mA.
…2 INSTALLATION
2.8 Relay Contact Protection and Interference
Suppression – Fig. 2.5
If the relays are used to switch loads on or off the relay contacts
can become eroded due to arcing. Arcing also produces radio
frequency interference (r.f.i.) which can cause instrument
malfunctions and incorrect readings. To minimize the effects of
r.f.i., arc suppression components are required; these are
resistor/capacitornetworksfor a.c.applications,ordiodes ford.c.
applications. These components can be connected either across
the load or directly across the relay contacts.
For a.c. applications the value of the resistor/capacitor network
depends on the load current and inductance that is switched.
Initially fit a 100 R/0.022 µF RC suppressor unit (part no. B9303)
Fig. 2.3 Location of User Junction Box Components
Fig. 2.4 Selecting The Current Output Range
Note.ThemainsandpumpON/OFF
switches are situated on the right
hand side of the junction box.
Caution. The AC power supply
ground cable must be connected to
the earth (ground) stud .
Caution. The protective
earth must be connected
to terminal 16.

7
2INSTALLATION
Fig. 2.5 Relay Contact Protection
NC C NO
External
DC Supply +–
Relay Contacts
Load
Diode
NC C NO
External
AC Supply LN
Relay Contacts
C
R
Load
A – AC Applications
B – DC Applications
Fig. 4.1 Nitrate Electrode
3SETTING UP
Note. Beforeproceedinganyfurther,ensurethatallswitches
are set to OFF on the right hand side of the electronics unit –
see Fig. 2.3.
a) Ensure that all external electrical and plumbing connections
have been made correctly.
b) Fillreagentandstandardsolutionbottlesandconnectthemto
the monitor. (See Section 8.1 for details of these solutions.)
c) Fit the probe according to the instructions in Section 8.2.6.
d) Connect the electrical supply and switch on.
Note.Thetemperaturecontrolled blockrequiresupto halfan
hour to reach the normal control temperature. During this
time, ‘Temp. Control Error’ is indicated on the display. Any
calibrations are prevented by the microprocessor during this
time.
e) Verify that there is an adequate supply of sample to the
monitor constant head unit.
f) Fit the pump platen on the peristaltic pumps (see Section
8.2.7) and switch the pumps on with the switch on the side of
the monitor. Ensure that the peristaltic pumps rotate, and
check that sample and reagents are being drawn into the
monitor by observing the progress of any small bubbles
present in the inlet tubes.
g) Runthemonitorfor at leastonehourtoallow the temperature
to stabilize, solutions to be pumped into the system and to
purge the air from the pipework. Check for any leaks around
the pipe connections and rectify as necessary.
h) Ifthe monitor exhibits good stability, i.e. ±2% of reading, carry
out a calibration – see Programming Page.
i) Check the condition of the sample filter and replace it if
necessary.Ensurethatnewfiltersarefittedcorrectlybytaking
note of the flow directions indicated on the filter bodies.
Output
Module 1
Link for the Current
Output required
Output Module 2
(if fitted)
Temperature Input
Module
Input
Module
Protection
Plate
Captive
Screws
0 to 1mA 0 to 10mA 0 to 20mA 4 to 20mA
18181818

8
4LIQUID HANDLING SECTION
4.1 Principle of Operation – Figs. 4.1
ThemonitorusesaNitrateIon–SelectiveElectrodeinconjunction
withadoublejunctionReferenceElectrode.TheNitrateElectrode
is a liquid membrane type sensor employing an ion–exchange
liquid in contact with the sample via a porous membrane. A
reservoir of liquid behind the membrane ensures a constant feed
ofexchanger.An inner central electrode containingagelledfilling
solutionmakesliquidcontactwiththebackofthemembrane.The
inner electrode is connected to main electronic unit via a
screened cable. It is useful to remember that the output from the
sensor is logarithmic with respect to the nitrate ion concentration.
The electro–chemical cell is completed by the reference
electrode, which generates a stable reference potential and is
also connected to the main electronic unit. It comprises a
reference element in a salt bridge container which is in contact
with an outer electrolyte via a porous ceramic junction. The outer
electrolytethencontactsthesampleviaanotherceramicjunction.
Thisdoublejunctionarrangementprotectstheinnerelementfrom
contamination.
Range of measurement can be set to any two consecutive
decades of concentration between 0.2 to 1000 mg l–1 as N or 1 to
5000 mg l–1 as NO3–.
Undertypicalcircumstances, with appropriate standardsolutions
and calibration frequencies, accuracies better than ±5% of
reading or 0.1 mg l–1 as N or 0.5 mg l–1 as NO3–whichever is the
greater, can be achieved.
Fig. 5.1 Electrical Connections Layout
4LIQUID HANDLING SECTION…
Sample
Inlet
Two Channel
Peristaltic Pump
To Electronics Section
Reference
Electrode
Electrode
Flowcell
Drain via
Constant
Head Unit
Heater Sample
Heater Coil
Nitrate
Electrode
Constant Head Unit
Sample / Calibrate
Solenoid Valves
Reagent Solution
Container
Standard
Solution 1
(Low)
Temperature
Sensor
Standard
Solution 2
(High)
SV1 SV2
Overflow
Drain
Contaminated
Drain
Out of Sample
Float Switch
From
Flowcell
Ion
Exchange
Solution
Filling
Aperture
Ion
Exchange
Solution
Bung
Gelled
Reference
Solution
Ag/AgCl
Reference
Electrode
Membrane
Washer
Body
Body Seal
Washer
End Cap
Membrane
Fig. 4.2 Flow Schematic