wtw LR 925/01 User manual

OPERATING MANUAL
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LR 925/01(-P)
ULTRAPURE WATER CONDUCTIVITY MEASURING CELL
LR 925/01
LR 925/01-P

Copyright © 2016 Xylem Analytics Germany GmbH
Printed in Germany.

LR 925/01(-P) Contents
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LR 925/01(-P) - Contents
1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1 Structure and function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.2 Recommended fields of application . . . . . . . . . . . . . . . . . . . . . 4
2 Measurement / Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1 Commissioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.2 Opening and closing the IDS plug connection (LR 925/01-P) . . 6
3 Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4 What to do if .... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5 Technical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
5.1 General data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
5.2 Measuring ranges and resolution . . . . . . . . . . . . . . . . . . . . . . 11
5.3 Accuracy of the IDS measuring technique . . . . . . . . . . . . . . . 11
6 Wear parts and accessories. . . . . . . . . . . . . . . . . . . . . . . . . 12

Overview LR 925/01(-P)
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OPERATING MANUAL
1Overview
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 communi-
cation with the meter even with long connection cables. If the sensor firmware
is enhanced by WTW, it can be updated with the meter.
1.2 Recommended fields of application
Measurements in ultrapure water.
1Shaft
2Connecting head with active sensor electronics
3IDS plug (LR 925/01-P)
4Connection cable (LR 925/01)
23
4
1
LR 925/01
LR 925/01-P

LR 925/01(-P) Measurement / Operation
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2 Measurement / Operation
2.1 Commissioning
Scope of delivery Conductivity measuring cellLR 925/01(-P)
Operating manual
Preparing the
sensor for
measurement
LR 925/01 Connect the sensor to the meter.The sensor is
immediately ready to measure.
LR 925/01-P Connect the sensor to an IDS connector of the
meter. To open and close the IDS plug connection
please follow the section 2.2 OPENING AND CLOSING
THE IDS PLUG CONNECTION (LR 925/01-P).
The sensor is immediately ready to measure.
Connection cables in different lengths to connect
the LR 925/01-P sensor to the meter are listed in
chapter 6 WEAR PARTS AND ACCESSORIES.

Measurement / Operation LR 925/01(-P)
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2.2 Opening and closing the IDS plug connection (LR 925/01-P)
This section only applies to the IDS plug variant, LR 925/01-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 togeth-
er, 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

LR 925/01(-P) Cleaning
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3 Cleaning
Note
To clean the sensor, disconnect it from the instrument.
Exterior cleaning We recommend to clean the sensor thoroughly, especially before measuring
low conductivity values.
After cleaning, thoroughly rinse with deionized water and recalibrate if neces-
sary.
Aging of the con-
ductivity measur-
ing 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 war-
ranty does not cover failure caused by measuring conditions and mechanical
damage.
Disposal We recommend to dispose of the measuring cell as electronic waste.
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

What to do if ... LR 925/01(-P)
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4 What to do if ...
Error symptom Cause Remedy
No temperature or con-
ductivity display
– No connection between meter and
conductivity measuring cell
– Cable defective
– Establish connection between
meter and conductivity measuring
cell
Measurement delivers
implausible 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

LR 925/01(-P) Technical data
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5 Technical data
5.1 General data
General features Measuring principle 2-electrodes measurement
Cell constant 0.100 cm-1 ± 2 %
Temperature sensor Integrated NTC 30 (30 kat 25 °C / 77 °F)
Dimensions
(in mm)
Weight LR 925/01 Approx. 90 g (without cable)
LR 925/01-P Approx. 95 g
Materials Shaft Stainless steel 1.4571
Connection head LR 925/01: POM
LR 925/01-P: POM
Conductivity electrodes Stainless steel 1.4571
Thermistor enclosure Stainless steel 1.4571
12.0
12.0
120.0
120.0
176.0
222.8
21.7
21.7
LR 925/01:
LR 925/01-P:

Technical data LR 925/01(-P)
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Connection cable Lengths LR 925/01: 1,5 m
LR 925/01-P: 1,5 / 3 / 6 / 10 / 15 / 20 m
Diameter 4.3 mm
Smallest allowed
bend radius
Fixed installation: 20 mm
Flexible use: 60 mm
Plug type Socket, 4 pins
IDS plug
(LR 925/01-P)
Type of connection 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 resis-
tance
Sensor with connection
cable
IP 68 (2 x 105Pa or 2 bar)
Cable plug IP 67 (when plugged in)
The LR 925/01(-P) meets the requirements according to article 3(3) of the
directive, 97/23/EC ("pressure equipment directive").
Measurement con-
ditions
Conductivity measuring
range
0.01 S/cm ... 200 S/cm
Temperature range -5 ... 70 °C (100 °C) 23 ... 158 °F (212 °F)
Max. admissible overpres-
sure
2 x 105Pa (2 bar)
Minimum depth of immer-
sion
30 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 (32 ... 122 °F)

LR 925/01(-P) Technical data
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5.2 Measuring ranges and resolution
5.3 Accuracy of the IDS measuring technique
Characteristics
when delivered
Temperature responding
behavior
t99 (99 % of the final value display after)
<20s
Accuracy of the temperature
sensor
± 0.2 K
Measuring ranges,
resolution
Measured parameter Measuring range Resolution
ӕ[µS/cm] 0.01 ... 19.99
0.0 ... 199.9
0.01
0.1
ρ(resistivity) [kOhm*cm] 5,00 ... 19,99
20.0 ... 199.9
200 ... 1999
0.01
0.1
1
ρ(resistivity) [MOhm*cm] 2.00 ... 19.99
20.0 ... 199.9
0.01
0.1
T [°C] 5,0 ... + 100,0 0.1
Measured parameter Accuracy (± 1 digit)
ӕ, ρ ± 0.5 % of measured value
T [°C] ± 0.1

Wear parts and accessories LR 925/01(-P)
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6 Wear parts and accessories
Accessories for
LR 925/01-P (IDS
plug variant)
Description Model Order no.
IDS connection cable, 1,5 m AS/IDS-1.5 903 850
IDS connection cable, 3 m AS/IDS-3 903 851
IDS connection cable, 6 m AS/IDS-6 903 852
IDS connection cable, 10 m AS/IDS-10 903 853
IDS connection cable, 15 m AS/IDS-15 903 854
IDS connection cable, 20 m AS/IDS-20 903 855
Blind plug for IDS plug (sensor) BPO/IDS 900 908 371
Blind plug for IDS socket (cable) BPI/IDS 900 908 370
Further accessories are listed in the price list of the WTW catalog
"Laboratory and field instrumentation".

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82362 Weilheim
Germany
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