CI-340 that is reading 100% humidity

CI-340 that is reading 100% humidity?

It is possible that the temperature sensor and PAR sensor are disconnected or malfunctioning. If the temperature sensor is not plugged in or malfunctioning, the unit will read 100% humidity and negative VPD Similarly, after having calibrated the unit, the PAR showing zero value indicates that the PAR sensor is either disconnected or malfunctioning.

If the PAR sensor is working correctly, you should be able to see movement in the PAR readings with a flashlight pointed at the unit from above. Note that the transpiration rate being 0 could be a result of the humidity sensors not reading properly (i.e., reading the same at the outlet as the inlet) Stomatal conductance will always be 0 if transpiration is reading 0, but if transpiration is reading a non-zero number and stomatal conductance is always reading 0 then that’s likely an issue with the leaf temp sensor.

If the unit is stuck “warming up” and will not take measurements, there is a possibility that the unit’s pump is no longer functioning properly. You can place the unit in “development mode” to confirm the pump voltage and flow and if needed.

To place the unit in development mode: Hold down the UP arrow button and then press POWER. The unit will display DEVELOPMENT MODE on the screen. Then press shift. Then press enter several times until the device powers off and back on again. The unit will display the pump voltage (VPUMP) and flow (FLOW DIFF.) with a message saying “warming up”.