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Optical IDS dissolved oxygen sensors

WTW sensors digital optical dissolved oxygen sensor (IDS) FDO® 925

FDO® 925 – optical oxygen sensors for applications in the lab and process, field and wastewater treatment systems - low-maintenance and quick

  • Saves time and money – low-maintenance & quick (t99 < 60s)
  • Flow-free with beveled membrane
  • Factory calibrated sensor cap with smart chip

The FDO® 925 is especially suited for lab and process thanks to its compact size. The flow-free, easy to clean beveled membrane allows it to be used in containers with low sample volumes. Also, low oxygen concentrations below 1 mg/l can be shown exactly.

Out in the field, the FDO® 925 convinces with its rapid response time and the available accessories, such as protective arming made of stainless steel or plastic. The cables are reinforced with Kevlar® and are available in various lengths, they ensure safe measurements in deep lakes or torrential rivers.

In wastewater treatment sites, the FDO® 925 shines during BSB measurements in the Karlsruhe bottle as well as during the monitoring of stationary measuring systems. In connection with the AutoRead function (monitors the stability of the sensor signal) of the MultiLine® devices, its response time can be adapted to that of the online sensor FDO® 700 IQ, which ensures comparable measured values.


Model Description Order no.
FDO® 925 Optical oxygen sensor, 1.5 fixed cable 201300
FDO® 925-3 Like above, 3 m fixed cable 201301

Technical Data

Concentration 0.00…20.00 mg/l ± 0.5 % of value
Saturation 0.0 … 200.0 %± 0.5 % of value
Partial pressure 0.0 to 400 hPa± 0.5 % of value
Temperature 0 … 50.0 °C ± 0.2 °C


Model Description Order no.
SC-FDO® 925 Replacement cap for FDO® 925 201310
FDO® Check Check/calibration container 201311
ADA FDO®/RZ Stirringn attachment, i.e. for BSB5 measurement 201312
FN FDO® Nut to attach the cap, without protective basket 201313
AS/IDS-1.5 Connecting cable for MPP IDS as well as plug head sensors, length 1.5 m 903850
AS/IDS-3 Like above, 3 m 903851
AS/IDS-6 Like above, 6 m 903852
AS/IDS-10 Like above, 10 m 903853
AS/IDS-15 Like above, 15 m 903854
AS/IDS-20 Like above, 20 m 903855
AS/IDS-25 Like above, 25 m 903856
AS/IDS-40 Like above, 40 m 903857
AS/IDS-60 Like above, 60 m 903858
AS/IDS-100 Like above, 100 m 903859
A 925-P Replacement head with existing protective basket 903838
A 925-P/K Arming for IDS –P sensors with protective basket made of POM 903839
A 925-P/S Arming for IDS –P sensors with protective basket made of stainless steel 903840
D 3Sen Flow vessel for field measurements 903842
KF 12 Karlsruhe bottle, minimum order 10 bottles 205700
TS 19 Funnel set for BSB5 determination with CellOx® 325/FDO® 925 in Winkler bottles, NS 19. 205710
FD 19/KA Fixation lid for Karlsruhe bottle KF 12 205711
FR 19 Fixation ring, recommended for measuring with Karlsruhe bottle for CellOx® 325 and FDO® 925 205712


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