FOOTAGE TOTALS:
SOLID FT SKIP FT
3920 626
FOOTAGE CAL NUMBER:
0.09780
* Mil calculation based on
line widths shown
All report items based on
calibration numbers.
Verify calibration frequently
to ensure correct reports.
--------------------------------
5.2 Datum Point
Datum point allows the skip timer to create a point in front of the guns that is the
target point for material.
This can be advantageous or even necessary in several situations:
➢
When bead coverage is critical when paint first turns on.
➢
For single-operator setups, where the operator is also the driver and/or cannot see the
guns.
➢
For high precision applications, so the vehicle can align with the target from the front
of the vehicle, allowing the vehicle to reach a reasonable application speed before
material is emitted from the guns.
5.2.1 The Bead Registration Concept
Beads are gravity fed and are relatively slow to reach the pavement (around 100
to 500 milliseconds depending on bead gun type and installation variables). In
comparison, high pressure paint reaches the road nearly instantaneously in
around five milliseconds.
Therefore, a properly operating skip timer will need to turn on the bead guns
before the paint guns. At 15MPH, a bead gun with 250ms total time delay turned
on electrically at the same time as a paint gun will have the beads arrive on the
ground ~5.5 feet AFTER the paint reaches the pavement. This is obviously
unacceptable in most situations.
This difference should only be corrected with time, and not with distance. If
5.5' is entered as a bead distance offset, and the vehicle subsequently is
operating at 10MPH, the beads will arrive 2.3' before the paint. This is obviously
SC-12 Road Marking Control System - Installation and Operation Manual
54
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