SEAT & MOUNTING GP 1988615 - Caterpillar

When Precise Laser Transmitter Alignment is Needed
When the following conditions apply, the laser transmitter requires precise alignment.
The laser transmitter is being used on steep slopes (1% or over).
You are working at long distances from the laser transmitter.
The job requires high accuracy.
Illustration 1 g00995119
Laser transmitter misalignment (1) Alignment Point 2 (2) Cross Axis Point 2 (3) 1° Pointing Error (4) Alignment Point 1 (5) Cross Axis Point 1The following scenario gives you some idea of the error that can be caused by misalignment of the laser. Assume that a laser transmitter has a 1 degree misalignment to the left side of the true direction centerline. There is also a 10 m distance between the direction centerline and Cross Axis Point 2. The grade in the direction axis is 0%. Illustration 1 shows this scenario.The following table shows the errors that are associated with the misalignment.
Table 1
Distance between Cross Axis point 1 and point 2 (Meters)     Cross Axis Grade (%)     Elevation Error (Meters)    
10     2.5     .004    
30     2.5     .013    
100     2.5     .131    
10     10     .017    
30     10     .052    
100     10     .523    Precise Laser Alignment Instructions
If you need to align the laser transmitter precisely, follow the instructions below:
Set up the laser transmitter directly over a reference point (alignment point 1).
Press the power button in order to turn on the laser and allow the laser to self-level. The laser always powers up in the automatic self-leveling mode. When the head begins transmitting, the laser is level.
Use the sighting grooves on the top of the laser transmitter in order to roughly align one axis to a second alignment stake (alignment point 2).
Enter a 0% grade into both axes (grade and cross slope).
By using a grade rod and laser receiver at point 2, adjust the laser receiver until you get an on-grade reading.
Illustration 2 g00995170
Precise alignment of the laser transmitter (1) Alignment Point 2 (2) 5% Cross Slope (3) Alignment Point 1
Enter a large grade (+5.000%) into the cross slope axis. This means that the laser plane is raising to the right side of the laser transmitter. Illustration 2 shows these points.
Take a second reading at point 2.If the second reading is equal to the first reading, the axis is aligned correctly.If the second reading is above on-grade, use the clockwise button on the laser transmitter to internally rotate the axis clockwise until you get an on-grade reading again.If the second reading is below on-grade, use the counterclockwise button on the laser transmitter to internally rotate the axis counterclockwise until you get an on-grade reading again.
The laser is now aligned, and you can enter the necessary percent of grade for the appropriate axes.Note: If you are using a laser transmitter that is equipped with a remote control, there is an automatic method of precise axis alignment available. Follow the instructions for the automatic axis alignment in the Operator's Manual for the laser transmitter.