Xylem WTW TetraCon 925 User manual

OPERATING MANUAL
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TetraCon®925 (/C)(-P)
CONDUCTIVITY CELL
TetraCon®925
TetraCon®925-P
TetraCon®925/C
OPERATING MANUAL

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TetraCon®925
2
Copyright © 2015, WTW GmbH
Reproduction in whole - or even in part - is prohibited without the
express written permission of WTW GmbH, Weilheim.
Printed in Germany.
For the most recent version of the manual, please visit
www.WTW.com.

TetraCon®925 (/C)(-P) Contents
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Contents
1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.1 Structure and function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.2 Recommended fields of application . . . . . . . . . . . . . . . . . . . . . . 5
2 Measuring / Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.1 Commissioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.2 Opening and closing the IDS plug connection
(TetraCon®925-P) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3 Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4 What to do if... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5 Technical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
5.1 General data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
5.2 Measuring ranges, resolution, accuracy . . . . . . . . . . . . . . . . . . 11
5.3 Accuracy of the IDS measuring technique . . . . . . . . . . . . . . . . 11
6 Wear parts and accessories . . . . . . . . . . . . . . . . . . . . . . . . . 12

Contents TetraCon®925 (/C)(-P)
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TetraCon®925 (/C)(-P) Overview
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1 Overview
1.1 Structure and function
Structure
Automatic sensor
recognition
The sensor electronics with the stored sensor data is in the connecting head.
The data include, among other things, the sensor type and series number.
With each calibration, the calibration data is written in the sensor and the
calibration history is recorded. The data is recalled by the meter when the
sensor is connected and is used for measurement and for measured value
documentation. Storing the calibration data in the sensor ensures that the
correct cell constant is automatically used if the sensor is operated with
several meters.
The digital transmission technique guarantees the failure-free
communication with the meter even with long connection cables. If the sensor
firmware is enhanced by WTW, it can be updated via the meter.
1.2 Recommended fields of application
On site measurements in rivers, lakes and wastewater
Fish farming
Ground water measurements
Applications in water laboratories
1Voltage electrode (inside, 2x)
2Current electrode (ring, 2x)
3Temperature sensor in graphite enclosure
4Shaft
5Connecting head with active electronics
6Connection cable (TetraCon®925(/C))
7IDS plug (TetraCon®925-P)
41, 2 3 5
6
7
TetraCon 925(/C)
®
TetraCon 925-P
®

Measuring / Operation TetraCon®925 (/C)(-P)
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Due to the use of high performance PEEK material for the connection
technology TetraCon®925/C has an improved chemical resistance,
especially in acid media (eg. As electroplating baths).
NOTE
Concentrated or strong oxidizing acids and organic solvents can
damage or destroy the sensor.
2 Measuring / Operation
2.1 Commissioning
Scope of delivery Conductivity measuring cellTetraCon®925 (/C)(-P)
Operating manual
Preparing the
sensor for
measurement
TetraCon®925(/C) Connect the sensor to the meter.
The sensor is immediately ready to measure.
TetraCon®925-P Connect the sensor to a free IDS sensor plug-in
position of the multi parameter probe or to an IDS
connection of the meter. To open and close the
IDS plug-in position please note the section 2.2
OPENING AND CLOSING THE IDS PLUG CONNECTION
(TETRACON®925-P).
The sensor is immediately ready to measure.
Connection cables in different lengths to connect
the TetraCon®925-P sensor to the meter are listed
in chapter 6 WEAR PARTS AND ACCESSORIES.

TetraCon®925 (/C)(-P) Measuring / Operation
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2.2 Opening and closing the IDS plug connection
(TetraCon®925-P)
This section only applies to the IDS plug variant, TetraCon®925-P.
Opening the plug
connection
If necessary, clean the plug connection
Open the locking device (step 1)
Use your thumb and index finger to press the clips of the connector
together, and pull the connector out of the plug (step 2).
Closing the plug
connection
Make sure that the plug connection is completely dry and clean.
Align the guidance of the connector with the groove in the plug and insert
the connector in the unlocked plug until it catches (step 3).
Close the locking device (step 4).
2
4
3
1
Plug connection
closed and locked
Guidance
Groove

Cleaning TetraCon®925 (/C)(-P)
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3 Cleaning
NOTE
Prior to cleaning, disconnect the sensor from the meter.
Outside cleaning We recommend to clean the sensor thoroughly, especially before measuring
low conductivity values.
After cleaning, thoroughly rinse with deionized water and recalibrate if
necessary.
Aging of the
conductivity
measuring cell
Normally, the conductivity measuring cell does not age. Special measuring
media (e.g. strong acids and bases, organic solvents) or temperatures that
are too high may considerably reduce its lifetime or lead to damage. The
warranty does not cover failure caused by measuring conditions and
mechanical damage.
Disposal We recommend to dispose of the measuring cell as electronic waste.
4 What to do if...
Contamination Cleaning procedure
Lime sediments Immerse in acetic acid for 5 minutes (volume
share = 10 %)
Fat/oil Clean with warm water that contains wash-
ing-up liquid
Error symptom Cause Remedy
No temperature or conductivity
display
– No connection between meter
and conductivity measuring
cell
– Cable defective
– Establish connection
between meter and
conductivity measuring
cell
Measurement delivers implausi-
ble conductivity values
– Measuring range exceeded
– Contamination in the area of
the electrodes
– Electrodes damaged
– Make sure the correct
sensor is being used for
the application
– Clean the conductivity
measuring cell (see
section 3).
– Return the sensor
Incorrect temperature display – The temperature sensor is not
immersed deep enough in the
measuring solution
– Temperature sensor
defective
– Observe the minimum
immersion depth
– Return the conductivity
measuring cell

TetraCon®925 (/C)(-P) Technical data
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5 Technical data
5.1 General data
General features Measuring principle Four-electrodes measurement
Cell constant 0.475 cm-1 ±1.5 %
Temperature sensor Integrated NTC 30 (30 kat 25 °C / 77 °F)
Dimensions
(in mm)
Weights TetraCon®925(/C) 60 g (without cable)
TetraCon®925-P 65 g
Materials Shaft Epoxy
Connection head TetraCon®925(-P):POM
TetraCon®925/C:PEEK
Conductivity electrodes Graphite
Thermistor enclosure Graphite
Connection cable Lengths TetraCon®925:1,5 / 3 m
TetraCon®925-P:
1,5 / 3 / 6 / 10 / 15 / 25 / 40 / 60 / 100 m
TetraCon®925/C:1,5 m
Diameter 4.3 mm
120,0
120,0
176,0
222,8
15,3
15,3
21,7
21,7
TetraCon 925(/C):
®
TetraCon 925-P:
®

Technical data TetraCon®925 (/C)(-P)
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Smallest allowed
bend radius
Fixed installation:20 mm
Flexible use:60 mm
Plug type Socket, 4 pins
IDS plug
(TetraCon®925-P)
Connection type 4-pole, watertight plug connection with lock,
reverse polarity protected
Materials Synthetic materials: Glass fiber reinforced
Noryl, TPU, TPC-ET, POM, PEEK, PBT
O-ring: FPM
Contacts gold-plated
Pressure
resistance
Sensor with connection
cable
IP 68 (2.5 x 105Pa or 2.5 bar)
Cable plug
(TetraCon®925)
IP 67 (when plugged in)
The TetraCon®925 (/C)(-P) meets the requirements according to article
3(3) of the directive, 97/23/EC ("pressure equipment directive").
Measurement
conditions
Conductivity measuring
range
1 S/cm ... 2 S/cm
Temperature range -5 ... 70 °C (100 °C) (23 ... 158 °F (212 °F))
Max. admissible overpres-
sure
TetraCon®925(/C):2,5 x 105Pa (2,5 bar)
TetraCon®925-P:1 x 106Pa (10 bar)
Minimum depth of immer-
sion
36 mm
Maximum depth of immer-
sion
(at temperature)
Whole sensor + cable up to 70 °C (158 °F)
Sensor shaft only (=120 mm) up to 100 °C
(212 °F)
Operating position Any
Storage conditions Recommended storing
method
In air
Storage temperature 0 ... 50 °C
Characteristic data
on delivery
Temperature responding
behavior
t99 (99 % of the final value display after)
<20s
Accuracy of the temperature
sensor
± 0,2 K