Surveying Instructions with NBMG's EDM Theodolite

Setting Up an Instrument Station

1. Place tripod over marker. Loosen the leg adjustments, lengthen the legs so plate is almost at eye level, then tighten again. Center tripod over marker using plumb bob. Push legs into ground with tabs near bottom, adjusting so plate is approximately level.

2. After tripod is set in ground try not to touch or bump legs. Do not lean on tripod.

3. Loosen tripod plate mounting screw and remove plastic plate cover. Use tabs on it to hang it on the tripod.

4. Open theodolite case. Lift theodolite by top (battery) handle only, never by telescope barrel. Wipe dust from plate and theodolite base. Place theodolite on tripod plate.

5. Engage mounting screw in theodolite base. Check optical plummet and slide theodolite gently on plate to center over marker. Then tighten the mounting screw securely.

6. Loosen the azimuth and vertical angle controls. Level the theodolite by first adjusting the knurled leveling screw wheels so bull's-eye level is centered. Then rotate azimuth so horizontal level spans between two leveling screws. Turn the screws in opposite directions; the bubble will move in the direction of the left screw. Turn instrument 90 degrees and level by adjusting the third screw only. Repeat this procedure once for each pair of screws. Rotate instrument to check levels.

7. Place prism target on rod and tighten locking ring. Extend rod so prism center is within 1 cm of theodolite objective height, with rod end resting on ground and in vertical orientation (check bull's-eye level on rod). Tighten knurled brass locking sleeve on rod. Measure prism and rod heights.

8. Sight true north with brunton compass. Remember to set local declination. Identify landmark on horizon in north direction. Send rodman out 30 m in that direction. Sight rod with brunton and wave rodman to north position.

9. Remove theodolite objective lens cap and replace with sun shade. Turn theodolite to sight on rod. Lock azimuth control. Turn instrument on with switch on battery handle. Wait 1 minute, then resight on rod using fine upper azimuth adjustments. Theodolite LCD panel should read some angle. Press 0-Set button to set north azimuth. Do not disturb lower azimuth lock.

Measuring a Station

1. Rodman and surveyor each have a radio. Keep power setting on low and channel at 3. Avoid draining the batteries with unnecessary conversation.

2. Rodman walks to station, announces the station number (written on flag) to surveyor by radio, and removes prism cap. The rodman holds rod vertically (continuously checking rod level) with prism pointing at theodolite. The rodman must remain still in this position until waved off or radioed by the surveyor.

3. When waved off, rodman replaces cap on prism and walks to next station. Upon reaching the station the rodman should automatically set the rod in position for measurement and radio the station number.

4. At the theodolite, the surveyor sights on the prism, first with the sight atop the telescope, then through the telescope. The outer eyepiece ring sets telescope focus; the innermost ring focuses the crosshairs. Note the station number reported by the rodman and check for consistency as measurements progress.

5. If battery voltage is adequate, surveyor locks the angle controls and uses the fine adjustments to position the crosshairs on the prism. Note the horizontal and vertical angles, using the V/H button to switch the display between the two. Read the angles to the recorder, taking care to notice any minuses at the left side of the display.

6. Begin laser ranging by pressing the triangle button. The instrument beeps periodically when the laser is on, consuming much power. After the instrument establishes the distance, press the triangle button to read the slope distance, horizontal distance, and vertical distance. Note any minuses.

7. Press the NEZ button to read delta-y (northing), delta-x (easting), and delta-z (elevation change), record with any minuses.

8. Halt laser ranging and conserve battery power by pressing the V/H button as soon as possible.

9. Wave off or radio the rodman to continue to the next station.

10. Check the theodolite leveling and carefully adjust if necessary, while rodman walks to next station.

Taking Down an Instrument Station

1. To put away theodolite, turn power off and unlock azimuth and vertical angles. Replace sunshade with objective cap.

2. Hold theodolite by battery handle. Loosen mounting screw and lift theodolite from tripod. Rotate base so white marks line up. Place theodolite in case with objective and lower angle lock down. Close case and latch.

3. Replace tripod plate cover and tighten mounting screw. Lift tripod, bring legs together, and loosen leg adjustments. Shorten legs and retighten. Bind legs with strap.

4. Put surveyor's notes in safe place. Remove prism from rod and put in padded case. Turn off radios.

5. Charge both battery handles and both radios each night.