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TECHNOGYM RUN Technical Service Guide
Rev. 1.0
3.8.1 BELT MOTOR ENCODER
In its simplest form, two parts can be distinguished:
•
the body, which is the fixed part, that houses the electric/electronic components (sensors,
circuits, etc.);
•
the rotor, which is the rotating part, that normally ends with a shaft to be connected to the
axis.
The electric output signals transmit the information relative to the position or movement of the rotor
with respect to the body.
In the relative encoders, the electric output signals are proportional to the movement of the rotor
with respect to the body, simple circuits can read and view the speed and acceleration of the relat-
ed axis, but not its instantaneous position.
The encoder is not an absolute type, which means that it does not indicate the exact position but
the speed. The encoder permits the drive to control the movement of the belt.
3.8.2 BELT MOTOR CONTROL
The CPU board (HK) communicates the set training profiles to the drive via the RS-485 serial com-
munication.
The drive puts the motor in motion by sending it a variable frequency sinusoidal voltage: as the
frequency varies, also the speed of the motor and therefore the speed of the tread belt varies.
During movement, the drive constantly controls the motor, monitoring the absorbed current. If prob-
lems are detected (undervoltage, over current, inverter SW and/or HW problems, etc.), it interrupts
the movement of the motor and generates an alarm signal towards the CPU board (HK).
Furthermore, to protect the motor from over-temperature problems, a thermal breaker has been
inserted in the motor that checks that the temperature does not exceed the threshold of the com-
ponent's range; if this threshold is exceeded, the NC contact opens, generating an inverter error,
the inverter stops the motor. This condition is detected by the drive as the opening of an external
NC-type contact. In that case, the drive interrupts the motor movement and sends an alarm signal
to the CPU board (HK).
3.8.3 INVOLVED SIGNALS
To summarise, the following signals are involved with the control:
•
RS-485 signal: It is a digital signal exchanged by the drive and CPU board (HK).
•
Variable frequency VAC signal: this is the alternating variable frequency voltage generated
by the drive to power the motor. As the frequency increases, the motor speed increases.
•
ENCODER signal: encoder frequency.
•
THERMAL PROBE signal: The motor is equipped with a thermal probe that has a normally
closed contact. When the temperature threshold is exceeded, the contact opens and caus-
es the motor to stop.
TSG-00284-EN- Uncontrolled copy if printed
- 35 -
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