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USER MANUAL
STM 550X / EMSIX
–
ENOCEAN MULTI-SENSOR
© 2020 EnOcean | www.enocean.com F-710-017, V1.0
STM 550x / EMSIx User Manual | v1.0 | February 2020 | Page 6/79
1
General description
This user manual describes the functionality of the family of multisensor modules STM 550x
and the family of Easyfit multisensor products EMSIx. An EMSIx Easyfit multisensor combines
an STM 550x module with a wall mount, a cover frame, a magnet and an adhesive mounting
tape into a ready to use product.
The STM 550x / EMSIx multisensor family consists of the following members:
◼
STM 550 and EMSIA using 868.3 MHz radio (main market Europe)
◼
STM 550U and EMSIU using 902.875 MHz radio (main market US / Canada)
◼
STM 550J and EMSIJ using 928.35 MHz radio (main market Japan)
The term “STM 550x” is used throughout this user manual to describe both EMSIx
Easyfit
multisensors and STM 550x multisensor modules in all frequency variants unless otherwise
noted.
1.1
Basic functionality
STM 550x is a flexible self-powered multi-sensor module family capable of measuring tem-
perature, humidity, illumination, magnet contact status and acceleration. It enables the re-
alization of energy harvesting wireless sensors for light, building or industrial control systems
communicating using the EnOcean radio standard.
STM 550x uses the same mechanical form factor as the industry standard PTM 21x modules
from EnOcean.
STM 550x implements the following sensors:
◼
Temperature
◼
Humidity
◼
Illumination
◼
Acceleration
◼
Magnet contact
STM 550x will report periodically (by default approximately every 60 seconds, configurable
via NFC) the latest measurements of these sensors. In addition, STM 550x can also report
its internal energy level and the amount of light available at the solar cell.
STM 550x will report immediately if the status (open / closed) of the magnet contact changes
or if a change in acceleration measured by the acceleration sensor exceeds a user-defined
threshold for the first time.
Radio telegrams transmitted by STM 550x can be encrypted and authenticated using AES-
128 security based on a device-unique private key and a sequence counter in accordance to
the EnOcean Alliance Security Specification. This ensures integrity, confidentiality and au-
thenticity of the transmitted telegrams and prevents telegram replay (retransmission of pre-
viously transmitted telegrams).
STM 550x is self-supplied via an integrated solar cell which generates the energy required
for its operation. For cases where ambient light is not sufficiently available, STM 550x pro-
vides the option to mount a CR1632 backup battery.