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User Manual May 2019 | Page 24/49
USER MANUAL
Scavenger Transmitter Module
STM 330 / STM 331 STM 331U / STM 332U / STM 333U
(Stepcode DE and later)
3.9
Configuration
3.9.1
Configuration via pins
The encoding input pins have to be left open or connected to GND in correspondence with
the following connection schemes. These settings are checked at every wake-up.
Wake-up cycle time
CW_0
CW_1
Wake-up cycle time
NC
GND
1 s ±20%
GND
NC
10 s ±20%
NC
NC
100 s ±20%
GND
GND
No cyclic wake-up
Redundant retransmission
Via CP_0 and CP_1 an internal counter is set which is decreased at every wake-up signal.
Once the counter reaches zero the redundant retransmission signal is sent.
CP_0 CP_1
Number of wake-ups that
trigger a redundant retransmission
GND
NC
Every timer wake-up signal
NC
NC
Every 7
th
- 14
th
timer wake-up signal, affected at random
NC
GND
Every 70
th
- 140
th
timer wake-up signal, affected at random
GND GND
No redundant retransmission
A radio telegram is always transmitted after wake-up via WAKE pins (unless the
WAKE1 (learn button) press-release sequence is not valid).
After transmission the counter is reset to a random value within the specified in-
terval.
According to FCC 15.231a) a redundant retransmission at every timer wake-up to
determine the system integrity is only allowed in safety and security applications!
In this case the total transmission time must not exceed two seconds per hour,
which means that a combination with a 1 s wake-up cycle time is not allowed!
If applied in other (non-safety, non-security) applications a minimum of 10 s be-
tween periodic transmissions is required. In addition the device has to comply with
the lower field strength limits of 15.231e). The limited modular approval of STM
33xU is not valid in this case.
