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Frequently Asked Wireless
Receiver Questions
What is the life expectancy of the
battery?
The battery life is expected to be 1.5+
years depending on the environment in
which the sensor is installed. The
sensor is designed to minimize the
frequency of communication while
maintaining space temperature control.
The sensor transmits on demand, such
as when the temperature changes, the
On/Cancel button is pushed, or the
thumbwheel is turned. The more
frequently the sensor transmits its
information the shorter the battery life.
A sensor in an entry will transmit the
temperature swing every time the door
opens but a sensor in an interior office
will transmit much less frequently.
The battery life of wireless zone
sensors is primarily due to the number
of times that the sensor reports to the
receiver. The sensor "senses" the
temperature every 10 seconds. The
maximum time a sensor will go without
reporting to the receiver is 420 seconds.
The minimum time the sensor will go
before reporting is 30 seconds.
Obviously, the more times the sensor
reports to the receiver, the shorter the
battery life will be.
What causes the sensor to report it's
"sensed" readings? There are two
things that cause the sensor to report:
1) changes or adjustments to the
thumbwheel set point, and 2)
temperature fluctuations greater than 1
degree F . The more the sensor reports,
the shorter the battery life will be. To
reduce the number of reports and thus
increase the battery life, avoid placing
the sensor in locations where
temperatures frequently fluctuate. Trane
recommends avoiding placing the
sensor in locations where "drafting" is
an issue such as lobby's, walkways, and
near computers. Also, sensors should
be placed at least at eye level to reduce
the effects of "drafts" created by people
walking by.
VAV-SVX01B-EN
Trouble
Analysis
What if I have other wireless systems
such as for security systems or
telephones? Can they interfere?
Trane Wireless VAV Systems apply
spread spectrum technology to
accomplish wireless communication.
Spread spectrum technology enhances
system security and allows the system
to operate in the same environment as
other systems using the same frequen-
cies. Upon reception, the receiver
"unspreads" the signal and reads the
information. Any receiver that does not
have a matching encoding sequence
can not unspread the signal and sees
the transmission as RF noise. This
spreading and unspreading enhances
the security of the system and its ability
to operate in the same environment as
other systems using the same frequen-
cies.
The sensor simultaneously broadcasts
identical information over two separate
frequencies (911 and 918 MHz) with a 5
MHz bandwidth, making interference
even less likely.
What about interference due to
building construction?
The spread spectrum technology is
very good at finding a way through the
building. However, if a building or an
area is enclosed in metal, the signal will
most likely not find a clean path to the
receiver. A large metal plane is the most
detrimental source of interference and
will most likely block the signal.
The signal will also have problems
penetrating steel reinforced concrete.
This means that unless there is a large
opening in the floor the signal may not
pass from floor to floor and a receiver
should be used on each floor. If a
system is configured using the
minimum amount of receivers and the
transmissions are getting lost the
obvious fix is to add a receiver.
Are there any environmental concerns?
The major environmental concern,
regarding batteries is mercury. The
battery that Trane uses contains no
mercury and thus is considered
environmentally friendly.
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