Hach POLYMETRON 8398 User manual

DOC024.52.93026
POLYMETRON Model 8398
Inductive Probe
User Manual
06/2015, Edition 5

Restriction of hazardous substances (RoHS)
The European Union RoHS Directive and subsequent regulations introduced in member states and
other countries limits the use of six hazardous substances used in the manufacturing of electrical and
electronic equipment.
Currently, monitoring and control instruments do not fall within the scope of the RoHS Directive,
however Hach Lange has taken the decision to adopt the recommendations in the Directive as the
target for all future product design and component purchasing.
Note: The following only applies to exports of this product into the People’s Republic of China.
Conductivity plastic sensor
(8310, 8311, 8312) O
Conductivity stainless
steel sensor (8314, 8394) OO
Digital sensor PCB O O
Glass electrode O O
O:
X:

Inductive Probe 8398
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Table of contents
1. INTRODUCTION................................................................................................ 3
1.1 General ....................................................................................................................3
1.2 Probes......................................................................................................................3
2. OPERATING PRINCIPLE.................................................................................. 4
2.1 Conductivity reminder ..............................................................................................4
2.2 Principle of inductive technology..............................................................................5
3. TECHNICAL SPECIFICATIONS ....................................................................... 6
3.1 Specifications ...........................................................................................................6
3.2 Compliance ..............................................................................................................7
4. PROBE START-UP ........................................................................................... 7
4.1 Cable connection .....................................................................................................7
4.2 Use with a 8921 conductimeter................................................................................8
4.3 Use with a 9125 conductimeter................................................................................9
5. PROBE CALIBRATION..................................................................................... 9
6. INSTALLATION PRECAUTION ...................................................................... 11
7. ACCESSORIES ............................................................................................... 13
7.1 Probe 8398.2, 2" clamp model (08398=A=2000)...................................................13
7.2 Probe 8398.3, DIN 11851 / DN50 dairy connection model (08398=A=3000) ........14
7.3 Probe 8398.5, 1" threaded model gas ...................................................................16
8. MAINTENANCE............................................................................................... 18
9. PRECAUTIONARY LABELS........................................................................... 19
10. CHEMICAL RESISTANCE TABLE ................................................................. 20

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1. INTRODUCTION
1.1 General
The 8398 range of probes makes use of inductive technology, which is particularly
recommended for corrosive and soiling uses, making use of conductivity or
concentration measurements. The main uses are as follows:
- Determination of solution concentrations: in-place cleaning, regeneration of
resin in water processing plants, surface treatment.
- Accurate interface control in conduits: in-place cleaning in the food and
pharmaceutical industries.
- Waste water testing: industrial and town sewerage plants.
1.2 Probes
WARNING: Non-removable cable!
8398.2 8398.3 8398.5
2''clamp DN50 dairy connection 1'' Gas

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2. OPERATING PRINCIPLE
2.1 Conductivity reminder
Electrolytic conductivity refers to the ability of a liquid to conduct an electrical current (conductivity is
the opposite of resistivity). In metals, the electrical current flows by electron displacement, in liquids it
flows by ion transport. The conductivity of a solution is dependent both upon the solution’s ionic
concentration and temperature.
To obtain a solution's actual conductivity (in S.cm-1), it is necessary to multiply the
measured conductance 1/R (in S) by a coefficient dependent solely upon the
geometry of the probe and termed "cell or K constant", expressed in cm-1.
R
K
C (S.cm-1)
In order to allow the comparison between measurements made at different
temperatures, this measurement needs to be brought back to a reference
temperature (generally 25 °C). This temperature dependency can be easily
expressed in the form of relative variation in degrees Celsius. It is referred to as the
temperature coefficient (D).
C Tref = C T[1 +
D
(T - Tref)]-1
C Tref : Conductivity compensated to the reference temperature
C T : Conductivity measured at T
Tref : Reference temperature (generally 25 °C)
D
: Temperature coefficient of the solution (% / °C)
Examples:
Product Soda (NaOH)
5 %
Nitric acid (HNO3)
10 %
D: 2.01 1.45
REMARK:
1 S = 1000 mS (R = 1 :)
1 mS = 1000 μS (R = 1 k:)

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2.2 Principle of inductive technology
1 : Receiver
2 : Oscillator
3 : Cables
4 : Thermoplastic insulator
5 : Receiver
6 : Transmitter
7 : Induced current
The 8398 probes are made up of two coils that are completely insulated from the
process:
xThe primary (or transmitter) coil, supplied with alternating voltage, produces an
alternating electromagnetic field that generates an electrical current in the solution.
xThe secondary (or receiver) coil detects the size of the weak current induced by
the movement of ions in the solution.
The absence of contact between the electrical part and the solution (magnetic
coupling) provides a large number of advantages compared to the traditional
technique using metallic electrodes:
x
No polarisation and hence a broad measurement range.
xHigh chemical and mechanical resistance.
xPossibility of performing measurements in soiling products.
xPerfectly hygienic design.

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3. TECHNICAL SPECIFICATIONS
3.1 Specifications
Measurement range 0 to 2000 mS/cm
Precision r2 % of the displayed value or r0.004 mS/cm
Conductivity response < 1 s
Temperature response T 50 % = 20 s
T 90 % = 2 mn
Cell constant K = 2.35 cm-1
Roughness Ra < 0.5 μm (roughness certificate on request,
Ref.: 08398=T=1111)
Chemical resistance Our mono-block probe is made from PEEC
(poly ether ether Ketone), whose chemical
resistance is summarised in the table §9.
WARNING: PEEC is not resistant to high
concentrations of oxidative acids (nitric and
sulphuric acid > 70 %, etc.) In the case of
probe 8398.5, one must consider the other
materials in contact with the process (EPDM or
VITON gaskets, PP or 316 stainless steel
extension, etc.).
Mechanical resistance PEEC possesses a flexion temperature
(pressure: 18 bars) of approximately 300 °C.
In the case of probe 8398.5, take account of
extensions, if any.
Heat resistance PEEC is a polymer that is particularly well-
suited to sterilisation, it can therefore withstand
temperatures of 140 °C.

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3.2 Compliance
iProbes are factory tested and are delivered with a certificate of compliance with
specifications.
Models 8398.2 and 8398.3 are particularly well-suited to applications where
sanitary requirements are extremely stringent (compliance with the European food
directive 90/128/CE modified by directive 93/9/CE). Indeed, these probes do not
possess any retention zones that could allow the development of bacteria
(interstices, slits, joints, etc.) and have a roughness inferior to 0.5 μm (optional
certificate, ref. 08398=T=1111).
iThe measurement chain, made up of an 8398 probe and of our conductivity
transmitters, complies with European directives 89/336/CEE and 73/23/CEE
modified by directive 93/68/CEE.
4. PROBE START-UP
4.1 Cable connection
WARNING: Fit the DN50 clamping nut or the immersion rod onto the probe before
wiring!
Make the following connections
COND 9125 COND 8921
(channels 1 and 2)
1 : GREEN or yellow (Pt100) TEMP + 14 and 19
2 : YELLOW or green (Pt100) TEMP - 15 and 20
GND 30 and 323 : BLACK (secondary coil shielding)
4 : WHITE (secondary coil) IN 31 and 33
GND 16 and 215 : BLACK (primary coil shielding)
6 : BROWN (primary coil) OUT 17 and 22
7 : WHITE (external shielding) EXTERNAL
SHIELDING
EXTERNAL SHIELDING
REMARK: The probe is fitted as standard with 5 metres of cable. We recommend
not cutting this cable in order to avoid any connection errors. If the
length is insufficient, please order the following accessories:
xJunction box, ref.: 08335=A=6000
xCable (per metre, maximum 50 m), ref.: 150727,10000

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4.2 Use with a 8921 conductimeter
The use of a type 8398 inductive probe connected to a type 8921 2-channel
conductimeter requires that this latter be fitted with a software version greater than or
equal to the following versions:
Software Minimum
version no.
Memory reference
Standard 3.76 08921=A=6200
Concentration 1.04 08921=A=6400
Special 4.07 08921=A=6305
To install your new software version, proceed as follows:
xRemove the transmitter's front panel (4 screws).
xOn the rear of the front panel, there are two circuit boards. Remove the first of
these two circuit boards (4 screws).
xAt the rear of this printed circuit board, carefully change the integrated circuit
(EPROM) represented on the figure opposite.
xCheck that the memory has been inserted in the correct position, otherwise it
would be irreversibly damaged.
xRe-fit the front panel and initialise the instrument's default parameters using
command 900.
xReprogram the instrument to your configuration and configure command C101
(102) with Argument 2, which corresponds to the 8398 probe's cell constant,
equal to 2.35.
EPROM

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4.3 Use with a 9125 conductimeter
Set the two switches (I/K) inside the instrument to position I.
Check that the measurement type is set to inductive.
5. PROBE CALIBRATION
REMARK: For more detailed information, see the user instructions of out 9125 and
8921 transmitters. We recommend proceeding in the following order:

Set the cell constant value on your transmitter to 2.35 cm-1.

Calibrate your temperature sensor:
Submerge the probe in a solution for approximately 10 min., raise the temperature of
this solution using a thermometer (accurate to r0.1°C if possible). Set the transmitter
to process calibration mode, then adjust the temperature value.

Calibrate conductivity (two solutions)
Electrical calibration:
Perform the "electrical" calibration of the probe with a decade box, using a wire no
longer than 50 cm and with a minimum cross-section of 0.38 mm².
The resistance values to use are: ffor zero adjustment (decade box disconnected):
then 200 Ohms (default instrument value) for slope adjustment:

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REMARK: After returning to measurement mode, the value displayed by the
transmitter takes account of the cell constant and also of
temperature compensation.
Example: 200 Ohms on decade box, T = 20 °C, transmitter set for 25 °C
compensation with a coefficient of 2 %, unit mS/cm:
DISPLAY: [2.35/200]. [1 + 0.02 u(20 - 25)]-1 = 13.06 mS/cm (c.f. Ch. 2-1)
Process calibration (9125 only):
During the first calibration of the chain, process calibration must be performed at two
distinct points (probe in air, then in the control solution).
After this, calibration can be performed on a single point (control solution only).
WARNING: If you are using a 9125 with software version < 1.12, the cell
constant value must be set prior to calibration.
Any alteration of the cell constant value after calibration would cancel the
calibration for this probe (slope reset to 100 %).

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6. INSTALLATION PRECAUTION
Minimum distance between probe and conduit
When the electrical field lines are partially obstructed by a wall, the measured
conductivity is altered (increased if the wall is a conductor, decreased if it is an
insulator). With our "high performance" shielding system, 100 % of the field lines of
our probe are channelled to within less than 10 mm, thus allowing measurements to
be made without disturbance in DN65 conduits.
It is also possible to perform measurements in DN50 conduits, using our DN65 /
DN50 converging / diverging T-pieces (reference 08398=A=6000 for 8398.3 probes
and 08398=A=7000 for 8398.2 probes). These T-pieces therefore allow users to
connect to DN50 conduits, while performing their measurements in a DN65 diameter.
WARNING: In order to work optimally, the probe must be completely submerged in
the liquid. We therefore recommend the use of a U-bend tube.

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Installation direction
The opening of the probe must face the conduit's flow direction, thus avoiding the
influence of flow rate and to perform the self-cleaning of this opening. For optimal
operation, the "POLYMETRON" marking should be positioned in the conduit's flow
direction, as shown in the following figure:
o
: flow direction in the conduit

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7. ACCESSORIES
There are three probe versions, that are distinguished by the type of connector used.
7.1 Probe 8398.2, 2" clamp model (08398=A=2000)
APPLICATION: FREE FLOW
Number: Reference: Designation Installation
1 581=000=510
2" stainless steel clamp collar -
2 429=500=510 EPDM joint for 2" clamp -
6 581=100=510 2" stainless steel ferrule to weld Min. DN65
1+2+6 08398=A=0510 Kit with 2" stainless collar
+ 2" EPDM joint + 2" stainless ferrule
Min. DN65
1+2+3 08398=A=7500 Kit with 2" stainless collar
+ 2" EPDM joint + DN65 stainless
T-piece
DN65
1+2+4 08398=A=7000 Kit with 2" stainless collar + 2" EPDM
joint + DN65/50 stainless T-piece
DN50
1+2+5 08398=A=8200 Kit with 2" stainless collar
+ 2" EPDM joint + Stainless flow
chamber (inlet / outlet 1/4" NPT)
Derivation

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7.2 Probe 8398.3, DIN 11851 / DN50 dairy connection model
(08398=A=3000)
APPLICATION: FREE FLOW

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Number: Reference:
Designation Installation
1 402=400=500
Stainless steel DN50 DIN screw
2 429=600=500 EPDM DIN DN50 joint
7 429=600=501 VITON DIN DN50 joint
6 581=200=500 DIN DN50 stainless steel ferrule to weld
(H = 35 mm)
1+2+6 08398=A=0500 Kit with DN50 stainless screw + EPDM
DN50 joint + DN50 stainless ferrule to
weld (H = 35 mm)
Min. DN65
1+7+8 08398=A=5310 Kit with DN50 stainless screw + VITON
DN50 joint + PVC ferrule to glue
(H = 23 mm)
Min. DN65
1+2+9 08398=A=5320 Kit with DN50 stainless screw + EPDM
DN50 joint + PP ferrule to weld
(H = 23 mm)
Min. DN65
1+7+10 08398=A=5330 Kit with DN50 stainless screw + VITON
DN50 joint + PVDF ferrule to weld
(H = 23 mm)
Min. DN65
1+2+4 08398=A=6000 Kit with DN50 stainless screw + EPDM
DN50 joint + DN65/50 T-piece
DN50
1+2+3 08398=A=6500 Kit with DN50 stainless screw + EPDM
DN50 joint + DN65 stainless T-piece
DN65
1+2+5 08398=A=8300 Kit with DN50 stainless screw + EPDM
DN50 joint + Stainless flow chamber
(inlet / outlet 1/4" NPT)
Derivation
1+7+11 08398=A=8310 Kit with DN50 stainless screw + VITON
DN50 joint + PVC flow chamber
(inlet / outlet 1/2" gas)
Derivation
1+2+12 08398=A=8320 Kit with DN50 stainless screw + EPDM
DN50 joint + PP flow chamber
(inlet / outlet 1/2" gas)
Derivation
1+7+13 08398=A=8330 Kit with DN50 stainless screw + VITON
DN50 joint + PVDF flow chamber
(inlet / outlet 1/2" gas)
Derivation

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7.3 Probe 8398.5, 1" threaded model gas
Remark: Flanges are not supplied individually.
This model is a universal model, specially adapted to immersion measurements. it is
supplied as standard with an EPDM sheet gasket, an optional Viton joint
(ref. 08398=C=3438) is also available, along with the stainless steel 1"G screw
(402=700=010).
We propose as standard several PP and 316 L stainless steel accessories for
immersion at various depths (0.5/1/1.5/2 m):

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Reference Material Immersion (m) Flange Immersion
setting
Adapter required
08335=A=5005 PP 0.5 DN65 PVC Adjustable
08398=A=1014
(H = 150 mm)
08335=A=5010 PP 1 DN65 PVC Adjustable 08398=A=1014
08335=A=5015 PP 1.5 DN65 PVC Adjustable 08398=A=1014
08335=A=5020 PP 2 DN65 PVC Adjustable 08398=A=1014
08398=A=6005 PP 0.5 DN50 PP Fixed -
08398=A=6010 PP 1 DN50 PP Fixed -
08398=A=6015 PP 1.5 DN50 PP Fixed -
08398=A=6020 PP 2 DN50 PP Fixed -
08398=A=6605 PP 0.5 DN50 PVC Adjustable -
08398=A=6610 PP 1 DN50 PVC Adjustable -
08398=A=6615 PP 1.5 DN50 PVC Adjustable -
08398=A=6620 PP 2 DN50 PVC Adjustable -
08350=A=1105 PP 0.5 - Clip 08398=C=0300
(H = 130 mm)
08350=A=1110 PP 1 - Clip 08398=C=0300
08350=A=1115 PP 1.5 - Clip 08398=C=0300
08350=A=1120 PP 2 - Clip 08398=C=0300
08878=A=1500 STAINLESS 1.5 (*) Adjustable 08398=C=0500
(*): No flange, to be used with 08878=C=1600 support