Documentation HG G-73650ZD | English, Revision 05 | Date: 09.03.2017 | www.goetting-agv.com
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Chapter 2: Basic Principles of Track Guidance
the number of segments. It is requested when the navigation controller is in the mode „Idle“
and bit 1 in byte 1 of the CAN Box Table 36 on page 114 is set to 1 (Segment Search Re-
quest).
While the segment search is active bit 1 in byte 1 in the CAN box Table 26 on page 105 will
be set (segment search active). On completion bit 2 in byte 1 of CAN Box, table 26 on page
107 is set (segment search finished). The drivable segments are collected in the CAN box
Table 26 on page 105 and transmitted to the vehicle control. When the bit "Segment Search
Request" is reset, the current segments of the navigation controller will again be sent in CAN
box Table 26 on page 105. This works analogously for the Feldbus telegram.
Additionally all drivable segments are permanently transmitted. The time it takes to identify
all drivable segments depends on the segment size and number. It can easily take some sec-
onds. The segment search must not be requested, as described above, but runs constantly
in the background. However, the list provided is only reliable after a few seconds of stand-
still.
2.5.2.3 Selection of Segments
The segments are chosen by the PLC and then sent to the navigation controller via the CAN
bus. For testing purposes the segments can alternatively be entered using a terminal pro-
gram or the keypad. To ensure that continual driving is possible the following segment must
always be known. Therefore the navigation controller has a segment memory with eight en-
tries in the for of a FIFO (First in First Out) shifting register (see image and tables below).
Figure 14
Segment FIFO shifting register
Segment
Segment
Segment
Support Point
Support Point
Support Point
Support Point
Segment
Segment
Segment
Segment
Track
Segment FIFO
shifting register
Completed
segments
Segments to
be driven
Segment
Segment
Segment
Segment
Segment
Segment
Register
No.
0
1
2
3
4
5
6
7