IQ Sensor Net System IQ Sensor Net FDO® Sensor Replacement Cap

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The replacement caps for the digital WTW IQ Sensor Net FDO® sensors are calibration free and provide reliable DIN compliant results. 

Product Features
  • Long lifetime (3-5 years)
  • Easy and fast replacement
  • Automatic recognition

WTW FDO® sensors are the perfect solution for measuring dissolved oxygen. In addition to being free of calibration and flow, with their 45° membrane, they are also insensitive to air bubbles. Therefore, you will not require any additional installation equipment. The robust design of this sensors allows the use with an overpressure of up to 10 bar. The special membrane has a unique stability and thus ensures stable measured values.

The calibration free WTW IQ Sensor Net FDO® Sensor Replacement Cap has a a long lifetime of 3-5 years (depending on application). This enables sustainable operation and minimal maintenance costs. The caps are recognized by the sensor automatically and immediately. This ensures the fastest possible restart of the measurement.

The typical cap for a wastewater treatment plant is the SC-FDO® 700, with a response time ideal for treatment processes. If a faster response time is needed to to the application, the cap SC-FDO® 701 can be used.

Available Versions:

  • SC-FDO 700 replacement cap FDO® 700 IQ (SKU: 201654)
  • SC-FDO 701 replacement cap FDO® 701 IQ (SKU: 201655)


Replacement caps for FDO® sensors - WTW
Measuring range (25 °C)
O2 concentration
0 ... 20.00 mg/l (0 ... 20.00 ppm)
O2 saturation
0 ... 200.0 %
O2 concentration
0.01 mg/l (0.01 ppm)
O2 saturation
0.1 %
< 1 mg/l (ppm): ± 0.05 mg/l (ppm) > 1mg/l (ppm): ± 0.1 mg/l (ppm)
Response time at 25 °C
t90: < 150 s t95: < 200 s
Minimum flow rate
No flow required
Non-sensitive to hydrogen sulfide, chlorine, and ionogenic substances
Operational temperature
23 °F ... 122 °F (-5 °C ... +50 °C)
Allowed pH range
4 … 12 pH
PMMA, PVC, silicone
Working life
2 years guaranteed with authorized use


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