Humidity transmitter for critical climate applications – Testo 6651

Model No: Testo 6651

Testo 6651 humidity/temperature transmitter for critical climate, accuracy up to ±1.7 %RH (depends on the probe), selectable signal outputs, optional display, optional ethernet module, optional relay, 2 analog outputs

  • High system availability thanks to integrated self-monitoring and early warning
  • Ethernet, relay and analog outputs enable optimum integration into individual automation systems
  • P2A software for parametrization, adjustment and analysis saves time and money during commissioning and maintenance
  • High measuring accuracy thanks to reliable and long-term stable humidity sensor technology


Not all measurement problems can be solved with “simple” transmitters. The testo 6651 meets special challenges. When combined with the probe series testo 660x, the testo 6651 becomes the first choice in demanding air conditioning technology as well as in many other applications. Optimum adjustment concept thanks to adjustment of the entire signal chain incl. analog adjustment Ethernet, relay and analog outputs allow optimum integration into individual automation systems Self-monitoring and early warning guarantee high system availability. Calculation and presentation of the humidity parameters relative humidity absolute humidity and dewpoint. P2A software for parameterization, adjustment and analysis saves time and costs in commissioning and maintenance.

Display with multi-language display. High-quality plastic housing

Delivery Scope

  • testo 6651 humidity/temperature transmitter including instruction manual
  • Factory certificate

Note: Please keep in mind that you need an attachable probe to commission the transmitter.

* When using the Ethernet function, we recommend ordering the P2A software in order to be able to make the network settings.


Datasheet Download Instruction Manual Download

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