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 11/97
2
Functional overview
2.1
Product description
The energy-harvesting multisensor module STM 550 provides wireless sensing functionality
without batteries. Power is provided by a connected solar cell. STM 550 transmits sensor data
using the EnOcean radio standard.
STM 550 operates fully self-powered (no batteries required) when sufficient available ambient
light (200 Lux for 6 hours per day) is available. In this configuration it is fully maintenance-
free.
For cases where sufficient ambient light is not available there is the option to mount a CR1632
backup battery.
Radio telegrams transmitted by STM 550 can be authenticated and encrypted 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 authentic-
ity of the transmitted telegrams and prevents telegram replay (retransmission of previously
transmitted telegrams).
2.2
Functional modes
STM 550 supports seven functional modes:
◼
Standard operation mode
◼
Standby (Sleep) mode
◼
Learn mode
◼
Function test mode
◼
Illumination test mode
◼
Acceleration test mode
◼
Factory reset mode
Out of the box, STM 550 will be in standby mode to conserve energy during
transport and storage. Upon initial setup, STM 550 has to be set to standard op-
eration mode by pressing the LRN button shortly as described in chapter 11.1 or
via the NFC interface as described in chapter 9.5.11