D6T8L06

MEMS Thermal Sensors D6T User’s Manual MEMS Thermal Sensors A284-E1-03 Table of Contents 1 2 3 4 5 6 Overview..................................................................................................................................2 Structure (Part Configuration) ..................................................................................................2 External Dimensions ................................................................................................................2 Principles of Operation ............................................................................................................2 Product Features .....................................................................................................................3 Usage Procedure .....................................................................................................................5 6.1 Connectors .......................................................................................................................5 6.2 Example Electrical Connections .......................................................................................6 6.3 I2C Specifications .............................................................................................................8 6.4 Example Temperature Value Retrieval Program .............................................................14 6.5 Example PEC Check Routine .........................................................................................17 6.6 Clock Stretch (Wait) ........................................................................................................18 6.7 Communication Timeouts ...............................................................................................19 6.8 Surface Cover Material ...................................................................................................19 6.9 Sensor Securement ........................................................................................................20 7 FAQ .......................................................................................................................................21 8 Definition of Terms .................................................................................................................22 1 D6T MEMS Thermal Sensors User’s Manual (A284) 1 Overview This user manual describes the usage procedures, precautions, and other information regarding D6T-series MEMS Thermal Sensors. This document also serves as a supplement to the product catalog. Reference this document together with the product catalog when using this device. 2 Structure (Part Configuration) The D6T series of MEMS Thermal Sensors consists of a small circuit board onto which a silicon lens, thermopile sensor, specialized analog circuit, and logic circuit for conversion to a digital temperature value are arranged. This product only requires one connector to connect these modules. 3 Fig. 1. Exterior of Module (Reference) External Dimensions This product features a circuit board size of 14 mm x 18 mm. An even more compact size of 11.6 mm x 12 mm is also available. Refer to the product catalog for more information on mounting areas and positioning of the circuit board. Refer to Chapter 6 for more information on compatible connectors. 4 Principles of Operation The following list describes an overview of the measuring operation of the MEMS Thermal Sensors. · The silicon lens focuses radiant heat (far-infrared rays) emitted from objects onto the thermopile sensor in the module. (*1) · The thermopile sensor generates electromotive force in accordance with the radiant energy (far-infrared rays) focused on it. · The values of this electromotive force and the internal thermal sensor are measured. Then, the device calculates the measured value (temperature of the object) via an interpolation calculation that compares the measured values with an internally stored lookup table. (*2) · The measured value is output via the I2C bus, and read using a host system. (Back side) I2C connector (Interior side) Thermopile sensor Silicon lens Fig. 2. Module Configuration (*1) The D6T-1A-01/02 models use a silicon filter. (*2) D6T-1A-01/D6T-1A-02/D6T-8L-09 use a temperature conversion circuit in the ASIC to calculate measured values (temperatures of objects). D6T MEMS Thermal Sensors User’s Manual (A284) 2 5 Product Features MEMS Thermal Sensors measure the surface temperature of objects. The D6T-44L-06 model features 16 channels in a 4 x 4 arrangement. The D6T-8L-09 features a single 8-channel array. The D6T-1A-01/-02 models feature a 1-channel sensor chip. The module has been optimized by placing the specialized downstream processing circuit adjacent to the sensor chip to achieve low-noise temperature measurements. Using our MEMS Thermal Sensors as a human sensor eliminates the problems in using conventional pyroelectric sensors to detect the presence of people. Pyroelectric sensors can be used to detect movement of people based on the principle of detecting change components of infrared rays, but the measurement signal is lost during times of no movement. Conversely, Thermal Sensors continue to generate a measurement signal during times of no movement. Pyroelectric Sensor Thermal Sensor (a) Output of pyroelectric sensor (b) Output of Thermal Sensor Fig. 3. Difference Between MEMS Thermal Sensor and Pyroelectric Sensor MEMS Thermal Sensors feature a silicon lens optically designed to have specific sensitivity characteristics. Our Thermal Sensors feature the same field of view (FOV) at a maximum sensitivity of 50% as general sensors. FOV Maximum sensitivity of 50% (a) Conceptual illustration of D6T-44L-06 FOV (16-channel) (b) Conceptual illustration of single-element FOV and XY-axis sensitivity characteristics Fig. 4. Field of View (FOV) and Sensitivity Characteristics Illustrations 3 D6T MEMS Thermal Sensors User’s Manual (A284) The sensitive areas of elements are wider than the FOV-specification width. If the size of the measured object is smaller than the sensitive area of an element, the background temperature of objects other than the intended object will become a factor. Our Thermal Sensors use a reference heat source (a blackbody furnace) to correct temperature values. However, note that differences in emissivity due to composition of measured objects, surface shape, and the occupancy ratio of objects within sensitive areas all affect temperature values. Distance: Close