Operation and Communication
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7.2
Operation Using Control Codes
In numerous positioning system applications, defined processes (= event) must be started at
specific positions. This means that the exact positions must be defined via code tapes for
positioning, instead of simple colored tapes. In the context of lane tracking, it is advisable to
mark branches using control codes to facilitate the control of the direction decision.
The layout of the lane can be adjusted according to the application in question. If an automated
guided vehicle must be positioned exactly, a code tape is mounted for positioning purposes
instead of the colored tape. If an event needs to start at a particular position or a direction
decision needs to be made, a control code is mounted parallel to the actual lane.
Only a specific event and the associated process then have to be programmed into the system
controller. The position in which the corresponding control code is placed next to the colored
tape or code tape for positioning does not have to be determined until final commissioning.
Even if subsequent changes are made to the layout of a system, the relevant control code is
simply moved to the new position without requiring program modifications to be made.
Control codes are short code tapes one meter in length. The control code has an encrypted
number. Control codes exist with numbers ranging from 001 to 999.
When the read head enters the range of a control code, it sets the control code flag in its output
data.
The 1-meter-long control code can be shortened. However, the minimum length should be 3
codes (60 mm). If the speed of the read head increases, a longer control code is required. If the
read head travels at maximum speed, a full-length control code of 1 meter must be positioned
next to the colored tape or code tape for positioning.
The minimum length of a control code can be calculated according to the following formula
depending on the travel speed and trigger period:
L
control code
= 60 mm + V
max
[m/s] * T
Trigger
[s] x 2
The trigger period is 40 ms.
Control codes are identified by the printed number, in this case "Control 12".
Figure 7.1
PGV-CC25-0012
The illustration shows part of control code #12
Refer to the "Accessories" chapter for order information relating to control codes.
Example!
Example calculation
The minimum length of the control code at a speed of 3 m/s and a trigger period of 40 ms is:
L
Event marker
= 60 mm + 3 m/s * 40 ms * 2 =
300 mm
