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Dissolved oxygen transmitter
Liquisys COM253

Compact field device for water, wastewater, utilities and fish farming

  • ©Endress+Hauser

Liquisys COM253 is a standard transmitter for use with COS41 and COS61 oxygen sensors. It improves your operational safety thanks to continuous plausibility, process and sensor checks. Select from numerous hardware and software modules, such as relays or fieldbus communication, to adapt it exactly to your measuring task. This modularity also allows you to upgrade the transmitter at any time. A simple menu and calibration make configuration and operation fast and easy.


  • More operational safety: Continuous process check system, customized alarm configuration, calibration plausibility check.

  • Reliable oxygen control: Current input for flow rate monitoring with controller shut off or for feedforward control.

  • Easy to operate and service: Simple single-point calibration in air, air-saturated water or in the medium, direct access for manual contact control.

  • Reduced maintenance: Automatic cleaning function (with Chemoclean) triggered by alarm or limit switch.

  • Fit for every application: Numerous extensions, e.g. P(ID) controller, timer, etc., allow for flexible adaption to all processes.

Field of application

The Liquisys COM253 transmitter works with Oxymax COS41 and Oxymax COS61 dissolved oxygen sensors in environmental applications, such as:

  • O2 control in the aeration basin

  • O2 control and monitoring of drinking water

  • Surface water monitoring

  • Process water treatment and monitoring

  • O2 control in fish farming for optimum growth conditions

Liquisys COM253 features the following protocols and interfaces:

  • 0/4...20 mA

  • HART



Features and specifications

Documents / Manuals / Software

Accessories / Spare parts

Predecessor / Successor

Predecessor: COM130, COM140, COM141, COM141S, COM151, COM240, COM240S, COM252, COM340

Success stories


Endress+Hauser Inc.
2350 Endress Place Greenwood , IN 46143 United States
Tel.: 888-363-7377
Fax: 317-535-8498
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