Theory Of Operation - Life Fitness 95L Service Manual

Models 95L, 95LWEZ, and 95LE Summit Trainers

Theory of Operation

THEORY OF OPERATION
The electronic system on the Summit Trainer consists of four main functional
blocks: 1) the console, 2) HR (heart rate) telemetry, and 3) the alternator, power
control board, and load, and 4) Lifepulse™ contact HR. The following is a
description of each block:
CONSOLE
The system voltage (6-7.5Vdc) enters on connector P2 pin 3 and is used to power
the LEDs and provide a supply voltage for the 5V-regulator circuitry used to power
the microprocessor section. The keypad entry (user input), Lifepulse, and
telemetry are all managed by the microprocessor. The console sends a PWM signal
to the power control board to control the duty cycle of the load.
HR TELEMETRY
®
HR Telemetry is implemented via a Polar receiver located in the monocolumn
cover at the front of the unit. The Polar receiver connects to the console at
connector P7.
ALTERNATOR, POWER CONTROL BOARD, AND LOAD
Using the PWM signal from the console, the power control board switches the
current on and off at the load via Q1. The control board also regulates the
alternator voltage using the U1. Q3 and Q9 are used to sense the reed switch
actuation ("autostart" feature).
LIFEPULSE
The bullhorn electrodes connect to the console board at connector P4. Pins 3 and 4
are signal, pins 1 and 2 are ground.
11