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User Manual May 2019 | Page 17/28
USER MANUAL
Energy Harvesting Magnet Contact Transmitter Module
STM 320 / STM 329 / STM 320U
(Stepcode DE and later)
4.2
Transmission range
The main factors that influence the system transmission range are type and location of the
antennas of the receiver and the transmitter, type of terrain and degree of obstruction of
the link path, sources of interference affecting the receiver, and “Dead” spots caused by
signal reflections from nearby conductive objects. Since the expected transmission range
strongly depends on this system conditions, range tests should categorically be performed
before notification of a particular range that will be attainable by a certain application.
The following figures for expected transmission range are considered by using a PTM, a
STM or a TCM radio transmitter device and the TCM radio receiver device with preinstalled
whip antenna and may be used as a rough guide only:
Line-of-sight connections: Typically 30 m range in corridors, up to 100 m in halls
Plasterboard walls / dry wood: Typically 30 m range, through max. 5 walls
Ferroconcrete walls / ceilings: Typically 10 m range, through max. 1 ceiling
Fire-safety walls, elevator shafts, staircases and supply areas should be considered as
screening.
The angle at which the transmitted signal hits the wall is very important. The effective wall
thickness – and with it the signal attenuation – varies according to this angle. Signals
should be transmitted as directly as possible through the wall. Wall niches should be avoid-
ed. Other factors restricting transmission range:
Switch mounted on metal surfaces (up to 30% loss of transmission range)
Hollow lightweight walls filled with insulating wool on metal foil
False ceilings with panels of metal or carbon fiber
Lead glass or glass with metal coating, steel furniture
The distance between EnOcean receivers and other transmitting devices such as comput-
ers, audio and video equipment that also emit high-frequency signals should be at least
0.5 m.
A summarized application note to determine the transmission range within buildings is
available as download from
4.3
Connecting an external backup battery
In case there is not sufficient light available for operation with solar cell an external 3 V
Lithium backup battery can be connected to the module at the soldering pads shown below:
