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3. EMI/RFI
This section provides the user with basic information about the problems with EMI,
known sources of EMI and protective measures either to reduce the possibility of
exposure or to minimize the degree of exposure. This section also shows some
conditions in which unexpected or erratic wheelchair movements may occur.
CAUTION
●It is very important that you read this information regarding the
possible effects of electromagnetic interference on your powered
KARMA wheelchair.
3.1 Electromagnetic Interference From Radio Wave Sources
3.1.1 Powered vehicles may be susceptible to electromagnetic interference (EMI),
which is interfering electromagnetic energy (EM) emitted from sources such as
radio stations (Radio Frequency Interference), TV stations, amateur radio
(HAM) transmitters, two-way radios, and cellular phones. The interference
(from radio wave sources) can cause the powered vehicle to release its brakes,
move by itself, or move in unintended directions. It can also permanently
damage the powered vehicle's control system. The intensity of the interfering
EM energy can be measured in volts per meter (V/m). Each powered vehicle
can resist EMI up to a certain intensity. This amount of resistance is called its
immunity level. The higher the immunity level, the greater the protection. At
this time, current technology is capable of achieving at least a 20 V/m
immunity level, which would provide useful protection from the more
common sources of radiated EMI. This powered vehicle model, with no further
modification, has an immunity level of 20 V/m without any accessories.
3.1.2 There are a number of sources of relatively intense electromagnetic fields in
our everyday environment. Some of these sources are obvious and easy to
avoid. Others are not apparent and exposure could be unavoidable. However,
we believe that by following the warnings listed below, your risk to EMI can be
greatly minimized.
