Cirrus Powerchair Owners Handbook
Page 5 of 24
Doc Code: PCC_IFU (02/15)
PERSONAL SAFETY (CONTINUED)
The intensity of the interfering EM energy can be measured in volts per metre
(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
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 wheelchair model as shipped,
with no further modification, has an immunity level of 20 V/m without any
accessories.
There are a number of sources of relatively intensive electromagnetic 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 believe that
by following the warnings listed below, your risk to EMI will be minimized.
The source of radiated EMI can be broadly classified into three types:
1.
Hand-held portable transceivers (transmitter-receivers with the antenna
mounted directly on the transmitting unit). Examples include citizens
band (CB) radios, walkie talkies, security, fire and police transceivers,
mobile phones and other personal communication devices.
2.
Medium range mobile transceivers, such as those used in police cars, fire
engines, ambulances and taxis. 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)
radios.
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 control system of the powerchair while
using these devices. This can affect powered wheelchair movement and braking.
Therefore, the warnings listed overleaf are recommended to prevent possible
interference with the control system of the powered wheelchair. Following the
warnings listed below should reduce the chance of unintended brake release or
movement as a result of EMI:
