Access Flow2A Manual page 16

16
The chair
The chair with a powered swivel seat can turn both 110⁰ clockwise and 110⁰ counter-clockwise, depending on the
rail and stairs. The electric motor is controlled by the electronics and the rotation is fully programmable in steps of
5⁰.
While moving, the chair is turned to the best position so that it can move up and down a narrow stairwell. At the
beginning and end of the travel the chair turns automatically to the position that provides the most room to make
stepping on and off easier.
Figure 3-7: Powered swivel seat
The desired rotation angle at any point along the rail is given by the recorded position of the carriage and the rail
data table which is programmed in the control boards memory. The required swivel angles are different for every
installed stairlift. The rotation angle is determined by an encoder. Additionally an opto coupler is used for detection
of the zero angle (reset) position (Figure 3-8). The zero position is detected when the flag has just left the opto
coupler. The motor is controlled in a feedback loop using the encoder of the swivel motor to achieve the desired
angle.
flag
Opto coupler
Figure 3-8: Swivel zero opto coupler Swivel squeeze opto coupler