
Instruction manual for the 
SCHOTT
® 
Instruments 
Conductivity measuring cells type 
LF 513T, 613T, 713T, 713T-250,  
LF 813T, 913T, 913T-ID, 
LF 1100+, 1100T+, 4100+, 5100+, 5100T+ 
®
®
Picture of exemplary electrodes 
®
SI Analytics GmbH 
Hattenbergstrasse 10 
55122 Mainz 
Germany 
Telefon +49 (0) 6131/66 5119 
Telefax +49 (0) 6131/66 5001 
e-mail: support@si-analytics.com 
www.si-analytics.com 
Putting into operation 
The LF913 T-ID conductivity measuring cell is equipped with an 
automatic sensor detection system in the connection plug. This system 
stores the sensor type and the serial number as well as the calibration 
data. To be able to use the automatic sensor detection feature, you will 
need a measurement device supporting this function. For further 
information, please refer to the operating instructions of the 
measurement device.  
2 pole measuring cells (LF1100+,1100T+, 4100+, 5100+, 5100T+, 
513T) are delivered platinated.  
4 channel and 5 channel conductivity measuring cells (LF613T, 713T 
713T-250 and LF 813T, 913T, 913T-ID) are immediately ready for use 
and do not need to be platinumplated. 
Please check the cell constant prior to the first use. The interval of the 
next following verification will depend on the circumstances of use.  
The conductivity measuring cell (except LF4100+) has to immerse by 
a minimum of 65 mm (ring mark) in the solution to be measured. The 
measurement value may be read off as soon as the signal has 
stabilised. In the case of temperature changes, this may take up to two 
minutes.  
The detachable threaded protection cap (only PPO shaft) at the front 
end of the measurement cell (LF513T, 613T, 813T) will protect the 
glass tube with the platinum rings and determines the cell constant. 
Storage and maintenance 
The storage conditions for conductivity measuring cells may be within 
the range of a 0-50°C and 5-95% relative humidity. Any conditions 
leading to condensation of water at the plug ought to be avoided. Prior 
to any extended period of storage, the electrodes (platinum rings) of 
the measuring cell should be cleaned, if applicable (please refer 
below), and the measuring cell should be stored in its original 
cardboard box. 
Cleaning 
Thorough cleaning is particularly recommended prior to measuring low 
conductivities. To clean the device, please detach the sensor. 
Unscrew and remove the protective cap (only LF513T, 613T, 813T) of 
the mesuring cell. 
2 pole measuring cells should only be rinsed with water, if necessary 
with diluted hydrochloric acid or sodium hydroxide. After mechanical 
treatment a platination is necessary, therefore the electrode can be 
sent to SI Analytics. 
Contamination on the sensor can be removed with the following 
procedure: 
Grease or oil, carefully clean the glass part and the ring electrodes 
using warm water containing a dishwashing detergent and a sponge. 
In the case of serious contamination, you may also gently remove it 
with an abrasive powder. In the presence of lime, please place the 
parts shortly (five minutes) in acetic acid (10Vol%). To clean the 
protective cap, please use a small bottle brush or a cotton bud.  
When using acids, leaches and solvents for cleaning, please make 
sure that they are compatible with the material of the shaft! 
An optimum cleaning of the inner glass part of the LF 713 T, LF 713T250 and LF 913 T-ID conductivity measuring cells is achieved with a 
tobacco pipe cleaner. The use of acids (exception: HF!), leaches and 
solvents is uncritical for these cells. 
Exemplified check and setting of the cell constant 
To verify the cell constant, you need test solutions, for instance the  
SI Analytics ampoules set LF 995. Immerse the measuring cell, 
except the LF 4100+, in a suitable test solution by a minimum of 65 
mm, for instance in KCl 0.01 mol/l. Then keep the temperature 
constant and set the corresponding conductivity value on the 
conductometer, for instance 1.413 mS/cm at 25°C for KCl 0.01 mol/l. 
For other solutions or different temperatures, please take the 
appropriate values from the table. To minimise the measuring 
incertainty over the entire range of use, calibration should be 
performed both at low and high conductivities. The appropriate cell 
constant should be set as a function of the measurement range. 
Setting and reading off of the cell constant is done according to the 
operating instructions of the conductometer used. 
Electrical conductivity mS/cm of KCl solutions as a function of 
temperature 
                KCl concentration mol/l
Temp.(°C) 0,001 0,01 0,1 1
18 0,127 1,225 11,19 98,24 
19 0,13 1,251 11,43 100,16 
20 0,133 1,278 11,67 102,09 
21 0,136 1,305 11,91 104,02 
22 0,138 1,332 12,15 105,94 
23 0,141 1,359 12,39 107,89 
24 0,144 1,386 12,64 109,84 
25 0,147 1,413 12,88 111,8
Quality 
Each electrode must meet the strict quality requirements of final 
testing. The working life depends mainly on the usage conditions. 
Hydrofluoric acid, sodium hydroxide and hot phosphoric acid attac 
glass. 
Further information 
Further informations can be found in the laboratory cataloque of    
SI Analytics GmbH. 
Subject to technical amendment. 
    GA_LF513-613-813-913_us_T814838_090504 
 

Plug pin configuration 
4 pole conductivity cell: LF 613T, 713T, 713T-250 
5 pole conductivity cell: LF 813T, 913T, 913T-ID 
NTC 
30kΩ 
8  NTC 
6  not used 
1  NTC 
4 Current electrode 1 
Screen + 
drain wire
2  Voltage electrode 1 
5  Voltage electrode 2 
3  Current electrode LF 813T, LF 913T, 
   LF 913T-ID, 2a, 2b 
7  Screen 
Plug pin configuration 
2 pole conductivity cell: LF 513 T 
8 NTC 
NTC 
30kΩ
6  not used 
1  NTC
4  Current electrode 
Pt 1000
2  Voltage electrode 
5  Voltage electrode 
3  Current electrode 
7  Screen 
Screen + 
drain wire
Plug, front view : 
2
5
4
3
1
7 6
Plug head configuration    
Configuration 2 pole conductivity cell:  
LF 1100+, 1100T+, 4100+, 5100+, 5100T+ 
4 Pt 1000  
5 Pt 1000 
1 Current electrode 
6 Voltage electrode  
3 Voltage electrode  
2 Current electrode  
Screen + 
drain wire
SMEK 
View on top of 
electrode head 
5
3
7
4
1
6