USER MANUAL
ETHSA / ETHSU
ENOCEAN TEMPERATURE AND HUMIDITY SENSOR
© 2022 EnOcean | www.enocean.com
F-710-017, V1.0
ETHSx User Manual | April 2022 | Page 17/27
3.7
Radio Telegram Timing
The setup of the ETHSx transmission timing reliably avoids possible collisions with data pack-
ages of other EnOcean transmitters as well as disturbances from the environment.
3.7.1
Standard Mode Transmission Timing
In Standard Mode with each transmission cycle, 3 identical subtelegrams are transmitted
within 40 ms. Transmission of a subtelegram lasts approximately 0.9 ms. The delay between
the three transmission bursts is affected at random.
Figure: Transmission timing in Standard Mode
3.7.2
Secure Mode Transmission Timing
In Secure Mode the transmission cycle is reduced to 2 identical subtelegrams that are trans-
mitted within 20 ms. This compensates the additional energy requirement of enhanced se-
curity computing and additional payload. The transmission of a subtelegram lasts approxi-
mately 1.2 ms.
3.8
Storing the Rolling code counter
For the enhanced security features a RLC counter needs to be stored in non-volatile memory.
For security reasons the RLC counter is incremented by every transmitted telegram. Together
with the CMAC the RLC ensures that messages cannot be reproduced or forged.
The RLC is stored in the Dolphin chip flash memory. To improve the endurance of the flash
memory and also the energy budget not every increment is saved to the non-volatile flash
memory. During deep sleep the RLC is stored in RAM0 memory.
0.00001
0.0001
0.001
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0.1
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Time [ms]
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