Operating manual
TetraCon 325
TetraCon 325/C
ba55301e03 02/2005
Standard conductivity cell
TetraCon 325 / TetraCon 325/C
Accuracy when
going to press
The use of advanced technology and the high quality standard of our
instruments are the result of continuous development. This may result in
differences between this operating manual and your instrument. Also, we
cannot guarantee that there are absolutely no errors in this manual.
Therefore, we are sure you will understand that we cannot accept any legal
claims resulting from the data, figures or descriptions.
10
Copyright
© Weilheim 2005, WTW GmbH
Reprinting - even as excerpts - is only allowed with the explicit written
authorization of WTW GmbH, Weilheim.
Printed in Germany.
TetraCon 325 / TetraCon 325/C Contents
List of contents
1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
1.1 Structure and function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
1.2 Recommended fields of application . . . . . . . . . . . . . . . . . . . . . 12
2 Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3 What to do if... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4 Technical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
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Overview TetraCon 325 / TetraCon 325/C
1 Overview
1.1 Structure and function
Structure
41, 2 3 5
1 Voltage electrode (inside, 2x)
2 Current electrode (ring, 2x)
3 Temperature sensor in a graphite enclosure
4 Shaft
5 Connection head
1.2 Recommended fields of application
l On site measurements in rivers, lakes and wastewater
l fishfarming
l Ground water measurements
l Applications in water laboratories
The TetraCon 325/C ist pa rticularly suitable for heavy chemical stress, particularly for acid media.
12
TetraCon 325 / TetraCon 325/C Cleaning
2 Cleaning
Caution
Before cleaning, disconnect the sensor from the instrument.
Cleaning A thorough cleaning is particularl y recommended for measurements of low
conductivities.
Contamination Cleaning procedure
Lime sediments Immerse in acetic acid for 5 minutes (volume
share = 10 %)
Fat/oil Clean with warm water that contains
washing-up liquid
After cleaning, thoroughly rinse with deionized water and recalibrate if
necessary.
Aging of the
conductivity
measuring cell
Disposal We recommend to dispose of the conductivity cell as electronic waste.
Normally, the conductivity measuring ce ll does not age. Special measuring
media (e.g. strong acids and ly es, organic solvents) or to o high temperatures
shorten the operational lifeti me considerably or damage the measuring cell.
The warranty does not cover cases where such conditions cause failure or
mechanical damage.
3 What to do if...
Error symptom Cause Remedy
No temperature or conductivity display
Measurement delivers
implausible conductivity
values
– No connection between
measuring instrument and sensor
– Cable defective
– Incorrect cell constant adjusted at
the measuring instrument
– Measuring range exceeded
– Contamination in the area of the
electrodes
– Electro de s damaged
– Check connection between
measuring instrument and sensor
– Check / correct the cell constant
– Observe the application range
– Clean the sensor (see section 2).
– Return the sensor
Incorrect temperature
display
– The temperature sensor was not
immersed deep enough in the
measuring solution
– Temperature sensor defective
– Observe the minimum immersion
depth
– Return the sensor
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Technical data TetraCon 325 / TetraCon 325/C
4 Technical data
General features Measuring principle Four-electrode measurement
Cell constant 0.475 cm
-1
±1.5 %
Temperature sensor integrated NTC 30 (30 k
Dimensions
162.5
(in mm)
120.0
15.3
Weight approx. 135 g
Materials Shaft Epoxy
Connection head TetraCon 325: POM
Plug connection for
DO module
Conductivity electrodes Graphite
21.7
17.5
TetraCon 325/C: PEEK
PEEK
W/ 25 °C)
Thermistor enclosure Graphite
Connection cable Lengths TetraCon 325: 1,5 / 3 / 6 / 10 / 15 / 20 m
TetraCon 325/C: 1,5 m
Diameter 6 mm
Smallest allowed
bend radius
Permanent bend: 80 mm
Single time or short time bend:50 mm
Plug type Socket, 8 pins
5
Pressure
resistance
Sensor with closed plug
connection
IP 68 (2 x 10
Pa or 2 bar)
Cable plug IP 67 (when plugged in)
The TetraCon 325 / TetraCon 325/C meets the requirements according to
article 3(3) of the 97/23/EC directive ("Pressure equipment directive").
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TetraCon 325 / TetraCon 325/C Technical data
Measurement
conditions
Storage
conditions
Characteristic data
on delivery
Conductivity measuring
mS/cm ... 2 S/cm
1
range
Temperature range -5 ... 80 °C (100 °C)
Max. allowed overpressure 2 x 105Pa (2 bar)
Minumum depth of immer-
36 mm
sion
Maximum depth of immer-
sion
Entire sensor+cable (up to 80 °C)
Sensor shaft only (=120 mm / up to 100 °C)
Operating position any
Recommended storing
in air
method
Storage temperature 0 ... 50 °C
Temperature responding
(99 % of the final value after) < 20 s
t
99
behavior
Precision of the temperature
±0.2K
sensor
Pin assignment
NTC
30 kW
8
NTC
6
not used
NTC
1
Current electrode 1
4
Voltage electrode 1
2
Voltage electrode 2
5
3
Current electrode 2
7
Shield
Plug from the front:
2
5
7
4
1
8
3
6
15
Technical data TetraCon 325 / TetraCon 325/C
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