USER MANUAL
STM 550 / EMSI
–
ENOCEAN MULTISENSOR FOR IOT APPLICATIONS
© 2020 EnOcean | www.enocean.com F-710-017, V1.0
STM 550 / EMSI User Manual | v1.3 | September 2020 | Page 14/97
2.3
Reporting interval
STM 550 will transmit its status as data telegram at a regular interval, the so-called reporting
interval. By default, the reporting interval is 60 seconds, i.e. STM 550 will measure and report
its status approximately once per minute.
STM 550 is designed to apply fluctuations up to +-10% to any configured reporting interval
to increase transmission reliability and meet regulatory requirements.
If STM 550 is configured to report acceleration, then it will always report the initial accelera-
tion detection after a period without detected acceleration immediately. Likewise, if STM 550
is configured to report magnet contact status, then it will report any change in the status of
the magnet contact sensor (open -> closed or closed -> open) immediately.
2.3.1
Energy considerations
The default reporting interval of 60 seconds (one update per minute) is adjustable using the
NFC interface as discussed in the subsequent chapters. The minimum possible reporting in-
terval is 3 seconds and the maximum possible transmission interval is 65535 seconds.
Lowering the reporting interval of STM 550 will increase its power consumption since it will
measure and transmit more often. Likewise, increasing the reporting interval of STM 550 will
reduce its power consumption since it will measure and transmit less often.
To select the right reporting interval, it is essential to determine the amount of harvestable
energy. STM 550 harvests energy from the available ambient light; therefore, the available
energy is determined by intensity and availability (time) of available ambient light.
The ambient light intensity can be determined by executing an illumination test as described
in chapter 2.2.5. The ambient light availability period needs to be determined based on the
lighting scheme used for the environment where STM 550 is installed.
STM 550 is designed to provide to operate self-supplied in its default configuration (one
update every 60 seconds) based on 200 lux of ambient light available for 6 hours per day.
The minimum supported update interval for self-supplied operation based on other conditions
is summarized in Table 1 below. Sufficient margin should be added in case the light level
might change.
6 hrs / day
8 hrs / day
10 hrs / day
12 hrs / day
50 lux
Not supported
Not supported
180 s
120 s
100 lux
120 s
90 s
90 s
60 s
150 lux
90 s
60 s
60 s
45 s
200 lux
60 s
45 s
45 s
30 s
300 lux
45 s
30 s
30 s
20 s
400 lux
30 s
25 s
25 s
15 s
500 lux
25 s
20 s
20 s
15 s
Table 1
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Minimum self-supplied reporting intervals