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The digital module EE894 measures carbon dioxide (CO2), relative humidity (RH), temperature (T) and ambient pressure (p). Temperature and pressure compensation ensures high CO2 measurement accuracy under changing environmental conditions. Very small dimension and the I2C or E2 interface facilitate the design-in.

The dual wavelength NDIR technology with auto-calibration is particularly long-term stable and insensitive to contamination. A multiple point CO2 and T factory adjustment leads to excellent CO2 measurement accuracy over the entire T working range. The pressure compensation minimizes the impact of altitude and ambient pressure variations onto the CO2 readings.

The measured data, with a range of up to 1% CO2, is available on the I²C or the E2 digital interface. Small dimensions and electrical connection via contact pins, edge card socket or pads facilitate the design-in.

An optional kit for the E2 interface facilitates easy configuration of the module and the adjustment of the CO2, RH, T and p measurement. The CO2 measurement interval can be set according to the application requirements; by this the average current consumption can be reduced to 420 μA, ideal for battery-operated devices.

Key features

  • Dual wavelength NDIR CO2 working principle
  • Measuring range up to 10,000ppm
  • Auto-calibration for excellent long term stability
  • Temperature and pressure compensation
  • High insensitivity to pollution
  • Easy user configuration and adjustment
  • Very low current consumption
  • Miniature size

Typical Applications

  • Demand controlled ventilation
  • Building automation
  • Data loggers and hand helds
  • Wireless transmitters

Technical data

  • 0...2000 ppm
    0...5000 ppm
    0...10000 ppm

    Measuring range CO2
  • ±(50 ppm +2% of mv)
    ±(50 ppm +3% of mv)
    ±(100 ppm +5% of mv)

    Accuracy CO2 at 25 °C (77 °F) and 1013 mbar (14.69 psi)
  • 0…95 % RH (non condensing)

    Measuring range Relative Humidity
  • typ. ± 3 % RH

    Accuracy Relative Humidity at 25 °C (77 °C) and 20...80% RH
  • 700…1100 mbar (10.15...15.95 psi)

    Measuring range Pressure
  • typ. ± 2 mbar

    Accuracy Pressure at 25 °C (77 °C) and 20...80% RH
  • -40…60 °C (-40...140 °F)

    Measuring range Temperature
  • typ. ± 0.5 °C (± 0.9 °F)

    Accuracy Temperature at 25 °C (77 °F)
  • I²C or E2

    Digital interface
  • 4.75-7.5V DC

    Supply

Product inquiry

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FAQ

  • What is the difference between E2 and I²C interface?

    I²C a standardized on-board serial interface between one controller and multiple devices using data and clock line. For details about I²C, please see NXP UM10204 I²C-bus specification and user manual, Rev. 6, 4 April 2014.

    E2 is a serial interface designed by E+E with unique command structure as well as reduced clock speed comparted to I²C. For more details about please see E2 Interface Specification

  • Which is the maximum cable length of E2 interface?

    The maximum cable length depends on the product, clock speed and pull-up resistor, and can be up to 10m. For detail please see E2 interface for humidity probes/modules

  • Which is the maximum cable length of I²C interface?

    I²C is an on-board interface, with bus lines up to 10cm. For longer bus please see the NXP wiring pattern.

  • How many E+E devices can be connected on one bus to a controller with E2 interface?

    Only one E+E device can be connected to the E2 interface of a controller.

  • How many E+E devices can be connected on one bus to a controller with i²C interface?

    Each I²C devices does have it's own ID by series, as long as this ID is unique in the bus this module or component could get built into the bus.

  • What is the difference between a 2 wire and a 3 wire current output?

    Transmitter with "two-wires" technology receive the power from the process, and the signal is carry on return wire (closed current loop). With technology "three-wires" the power supply is separate from current output: 2 wires are the power supply and third carry the signal.