Heart Rate System (Hr) - Life Fitness Weekly Service Manual

Heart Rate System (HR)

Polar ® Telemetry Receiver:
The Polar Telemetry receiver used in this generation of product is the CODED telemetry receiver.
A coded telemetry receiver has the following characteristics:
• The maximum range of the transmitter is three feet (one meter).
• The initial range of the transmitter is one foot (0.3 meter).
• To establish a connection, user must stand within one foot of the receiver. It may take up to one minute to establish
successful coded communication.
• This receiver works fine with the non-coded telemetry chest strap.
• The in-chest strap battery may not be replaceable. For troubleshooting use a telemetry simulator sold by Polar.
• It is not immune to EMI - the previous version was not either.
• It does not guarantee complete protection against cross-talk, but only minimizes the chances of it happening.
NOTE: The telemetry receiver is mounted in the console bezel.
The in-console coded Polar receiver works best with the coded telemetry straps (although non coded straps are
supported as well).
The coded chest strap, after establishing a code with the telemetry receiver, sends out user's heart rate in a form of a
pulse. A non-coded chest strap sends user's heart rate in a similar fashion.
The performance of the telemetry heart rate system is dependent upon a number of factors:
• Conductivity of the signal from user's chest to the telemetry chest strap (sensors must be clean, moist, user's skin
and electrical properties must foster electrical signal conductivity).
• The condition of the chest strap battery must be good (often there is no method to check it, since this battery is not
replaceable).
• The condition of the chest strap electrodes (they must not be broken).
• Electromagnetic Interference (usual EMI suspects are: fluorescent lighting, high power lines, home appliances,
personal electronics).
• Proper grounding of the product at the power outlet.
• Proper orientation of the Polar receiver: longer side MUST be parallel to the floor.
• Proper mounting of the Polar receiver in the product. If it falls off, it will change the antenna orientation.
IMPORTANT: You must be properly grounded with an ESD strap when replacing the Polar telemetry board.
Lifepulse ™ Theory of Operation
The Lifepulse contact heart rate system is designed to sense the electrical signals originating from the heart as it beats
and, using software, compute and display the corresponding heart rate value on the console readout. The two pairs of
electrodes on the Treadmill Ergo bar (left and right) are the point of contact at which these signals are picked up and
transmitted from the body to the Lifepulse circuitry. A hands-on detect circuit monitors for a change in voltage
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