General Information On Electromagnetic Interference - Otto Bock Skippi Plus Instructions For Use Manual

Safety
2.7.1 General information on electromagnetic interfer-
ence
„ Power wheelchairs may be susceptible to electromag-
netic interference (EMI), which is interfering electromag-
netic energy (EM) emitted from sources such as radio
stations, TV stations, amateur radio (HAM) transmitters,
two-way radios, and mobile phones.
„ The interference (from radio wave sources) can cause
the power wheelchair to release its brakes, move by it-
self, or move in unintended directions.
„ It can also permanently damage the power wheelchairs
control system.
„ The intensity of the interfering EM energy can be meas-
ured in volts per meter (V/m). Each power wheelchair
can resist EMI up to a certain intensity. This is called its
"immunity level". The higher the immunity level, the great-
er the protection. At this time, current technology is ca-
pable of achieving at least a 20 V/m immunity level,
which would provide useful protection from the more
common sources of radiated EMI.
„ There are a number of sources of relatively intense elec-
tromagnetic fields in the everyday environment. Some of
these sources are obvious and easy to avoid. Others are
not apparent and exposure is unavoidable. However, we
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believe that by following the warnings listed below, your
risk to EMI will be minimised.
„ The sources of radiated EMI can be broadly classified
into three types:
1. Hand-held portable transceivers (transmitters-receiv-
ers) with the antenna mounted directly on the trans-
mitting unit. Examples include: citizens band (CB) ra-
dios, "walkie talkie," security, fire, and police
transceivers, mobile telephones, and other personal
communication devices.
Some mobile telephones and similar devic-
NOTICE
es transmit signals while they are ON, even when
not being used.
2. Medium-range mobile transceivers, such as those
used in police cars, fire trucks, ambulances, and tax-
is. These usually have the antenna mounted on the
outside of the vehicle;
3. Long-range transmitters and transceivers, such as
commercial broadcast transmitters (radio and TV
broadcast antenna towers) and amateur (HAM) ra-
dios.
„ Because EM energy rapidly becomes more intense as
one move closer to the transmitting antenna (source), the
EM fields from hand-held radio wave sources (transceiv-
Skippi Plus