Guidance Control in Detail
English, Revision 07, Date: 07.03.2018
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Figure 8
Segment FIFO shifting register
2.1.1.2
Segment search
When the guidance of the vehicle is initialized, only one position of the vehicle is
known at first. To identify the currently drivable segments and to transmit them to the
central control unit, a segment search can be carried out. During the segment search,
the track controller tests all the segments stored for drivability. The segment search
can take several seconds depending on the number of segments. It is triggered by
setting bit 4 in byte 1 of CAN Box 0x194. The steering controller must be in "waiting"
mode (stand-by). On completion bit 5 in byte 1 in the CAN box 0x185 will be set (seg-
ment search completed). The positively found segments are transmitted as a segment
listing in box 0x195 to the vehicle control unit. If the „segment-search“-bit is set to 0,
the current segments will be transmittet in the segment list of box 0x195.
2.1.1.3
Specifiying the segments
The vehicle control unit specifies the segments to the steering controller via CAN bus.
For testing purposes, they can also be specified via a terminal program or the key-
board. To ensure that continual driving is possible, the connecting segment must al-
ways be known. Therefore the steering controller has a segment memory with eight
entries designed asa FIFO (First in First Out) shift register (see Figure 8 above). Seg-
ment 0 is the current segment. Segment 1 is the next segment. Segment 7 is the last
segment in the FIFO register: If the FIFO register does not have 8 segments, the rest
of the entries are filled up with 255 (Note: 0 is a valid segment number). If the vehicle
is finished with a segment, it is pushed out of the FIFO register and the next segments
move up.
