Determining the Height of Instrument (HI)
The height of instrument (HI) is the elevation of the laser’s beam. The HI is determined
by adding the grade-rod reading to a benchmark or known elevation.
1. Set up and level the laser.
2. Attach the receiver to a grade rod and turn on the receiver.
3. Place the grade rod on a job-site benchmark (BM) or known elevation.
4. Slide the receiver up/down the grade rod until the LCD shows an on-grade reading.
5. Add the grade-rod reading to the benchmark to determine the height of instrument.
Example: Benchmark elevation = 100.23 ft (30.55 m)
On-grade rod reading = + 4.34 ft (1.32 m)
Height of instrument = 104.57 ft (31.87 m)
6. Use this HI as a reference for all other elevations.
© Trimble Engineering and Construction Division, 5475 Kellenburger Road, Dayton, Ohio 45424-1099, (937) 233-8921, FAX: (937) 233-9004
www.Trimble.com Reorder No. 1044-0930 02/02
N324
HI
Rod Reading
4.34 ft (1.32 m)
Benchmark
100.23 ft (30.55 m)
HI = Rod Reading + Benchmark
HI = 4.34 ft + 100.23 ft = 104.57 ft (1.32 m + 30.55 m = 31.87 m)
Height of Instrument (HI)
To Previous Page
Loading...
