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SAFETY SUMMARY
CAUTION:
T IS VERY IMPORTANT THAT YOU READ THIS INFORMATION REGARDING THE POSSIBLE EFFECTS OF ELEC-
TROMAGNETIC INTERFERENCE ON YOUR POWERED WHEELCHAIR.
WARNING
Electromagnetic Interference (EMI) From Radio Wave sources
Powered wheelchairs and motorized scooters (in this text, both will be referred to as powered wheel-
chairs) may be susceptible to electromagnetic interference (EMI), which is interfering electromag-
netic energy (EM) emitted from sources such as radio stations, TV stations, amateur radio (HAM) trans-
mitters, two way radios, and cellular phones. The interference (from radio wave sources) can cause
the powered wheelchair to release its brakes, move by itself, or move in unintended directions. It can
also permanently damage the powered wheelchair's control system. The intensity of the interfering EM
energy can be measured in volts per meter (V/m). Each powered wheelchair can resist EMI up to a
certain intensity. This is called its "immunity level." The higher the immunity level, the greater the protec-
tion. 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 wheel-
chair model as shipped, with the MKIV-RII-LP controller has an unknown immunity level.
There are a number of sources of relatively intense electromagnetic fields in the everyday environ-
ment. Some of these sources are obvious and easy to avoid. Others are not apparent and exposure is
unavoidable. However, we believe that by following the warnings listed, your risk to EMI will be mini-
mized.
The sources of radiated EMI can be broadly classified into three types:
1) Hand-held Portable transceivers (transmitters-receivers with the antenna mounted directly on the
transmitting unit. Examples include: citizens band (CB) radios, "walkie talkie," security, fire, And police
transceivers, cellular telephones, and other personal communication devices.
**NOTE: Some cellular telephones and similar devices 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
taxis. These usually have the antenna mounted on the outside of the vehicle; and
3) Long-range transmitters and transceivers, such as commercial broadcast transmitters (radio and TV
broadcast antenna towers) and amateur (HAM) radios.
NOTE: Other types of hand-held devices, such as cordless phones, laptop computers, AM/FM radios, TV sets,
CD players, cassette players, and small appliances, such as electric shavers and hair dryers, so far as we know,
are not likely to cause EMI problems to your powered wheelchair.
Powered Wheelchair Electromagnetic Interference (EMI)
Because EM energy rapidly becomes more intense as one moves closer to the transmitting antenna
(source), the EM fields from hand-held radio wave sources (transceivers) are of special concern. It is
possible to unintentionally bring high levels of EM energy very close to the powered wheelchair's con-
trol system while using these devices. This can affect powered wheelchair movement and braking.
Therefore, the warnings listed are recommended to prevent possible interference with the control
system of the powered wheelchair.
SAFETY SUMMARY (CONTINUED)
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