EVB90614 Melexis Inc, EVB90614 Datasheet - Page 19

• Manufacturer Part Number: EVB90614
• Description: BOARD EVAL FOR MLX90614
• Manufacturer: Melexis Inc

Specifications of EVB90614

• Sensor Type: Temperature
• Sensing Range: -40°C ~ 125°C
• Interface: SMBus (2-Wire/I²C)
• Embedded: Yes, MCU, 8-Bit
• Utilized Ic / Part: MLX90614
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Supply: -
• Sensitivity: -

5.8
with emissivity lower than 1 is measured. Most materials have an emissivity close to 1 and
a correction is not needed.
This routine can also be used to compensate for IR windows or IR lenses one wants to
place between the object and the sensor in order to protect the sensor or make changes in
the FOV. This can only be successful if one takes care to keep the window or lens at the
same temperature as the sensor.
ambient and object temperatures measurable by the thermometer, but will have the highest
accuracy at the object and ambient temperatures used during the “calibration”.
To determine the emissivity it is necessary to know the object temperature accurately.
This can be done by either using a contact thermometer or by painting part of the object
black with thin layer of high temperature paint.
measured with the MLX90614 pointing at the painted area and the emissivity can be
determined with the MLX90614 pointing at the unpainted area.
It is assumed that the MLX90614 sensor has the same temperature as the area
surrounding the object and sensor. The calculation of the emissivity correction is highly
sensitive to this temperature. The EVB can heat up the sensor 1-2degrees. For this
specific measurement it is advised to mount the sensor away from the EVB and make the
SMBus interface using connector 1) on the EVB (see figure 4.1).
The emissivity coefficient is calculated using the formula:
Where:
Tomeas - the object temperature measured from MLX90614
Ta
Toreal
The automatic emissivity correction option is available from Advanced ->Emissivity.
The “K-Emissivity correction” window appears (Fig. 5.27) inviting the user to enter the real
temperature Toreal of the object. Push OK button to start the measurement of Tomeas and
Ta and the calculation of Ke. The sensor must be looking at the object at that moment.
390129061401
Rev 004
Automatic emissivity compensation
This option allows automatic emissivity compensation in a MLX90614 when an object
.
- the ambient temperature measured from MLX90614
- the real object temperature
Ke
The emissivity compensation will be active for all
=
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Tomeas
Toreal
Fig. 5.27
4
4
−
−
Ta
Ta
4
4
The real temperature can then be
MLX90614 Evaluation board
USER MANUAL
User Manual
Jan/2008