19 D6T MEMS Thermal Sensors User’s Manual (A284)
6.7 Communication Timeouts
This sensor determines that a timeout has occurred and stops communication if low input
continues to be received on the SDA or SCL terminal for the following times.
· D6T-44L-06 : 1 sec
· D6T-1A-01/D6T-1A-02/D6T-8L-09 : 70 msec
When the sensor determines that a communication timeout has occurred, a NACK is returned
during a Write access operation. For Read access operations, the read value is set to FFFFh.
Using PEC for data checking enables the system to determine that read values are in error.
As such, we recommend using PEC data checking.
6.8 Surface Cover Material
Make sure that cover material used when installing the MEMS Thermal Sensor as part of an
assembly has sufficient radiant heat (far-infrared) transmissivity. A far-infrared transmissive
grade of high-density polyethylene (HDPE) is often used as a cover material due to being
relatively inexpensive and easy to mold. The rate of decay varies depending on cover
thickness, and so make the cover as thin as possible to reduce negative impact on detection
performance. However, if the cover is too thin, the internal sensor will be visible as illustrated
in the following photos.
None cover HDPE( t0.7 )
54.9%
H
DPE( t0.5 ) HDPE( t0.3 )
60.1%
71.5%
100%
Fig. 23. Relationship Between HDPE Thickness and Transparency (Reference)
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