Maintenance Protocols Flashcards

Which field test is used to check the line-of-sight (collimation) error of an automatic level?

Answer: Two-peg test

The two-peg test compares elevation differences from a midpoint setup and an end setup to reveal collimation error.

When adjusting a circular (bull's-eye) bubble that runs off center after rotating the instrument 180°, how much of the error is removed with the bubble adjusting screws?

Answer: Half

Rotating 180° doubles the error, so half is corrected with the adjusting screws and the rest with the leveling screws.

A total station is moved from a 20°C truck cab to a 5°C job site. Following the common manufacturer rule of thumb, about how long should it acclimate before precise measuring?

Answer: About 30 minutes

A common guideline is roughly 2 minutes per °C of temperature difference, so a 15°C change needs about 30 minutes.

What is the recommended way to dry a total station that got wet in the rain?

Answer: Leave it out of the case at room temperature until fully dry

Air drying out of the case at moderate temperature lets moisture escape, while a closed case traps it and causes condensation.

What is the best way to clean the objective lens of a surveying instrument?

Answer: Blow off loose dust, then wipe gently with lens tissue and pure alcohol if needed

Removing grit first and then using lens tissue with a proper solvent prevents scratching the lens coatings.

After use near salt water, what should be done to a steel tape before storing it?

Answer: Wipe it clean and dry, then apply a light coat of oil

Cleaning, drying, and lightly oiling a steel tape prevents rust that can weaken it and affect readings.

Which observation reveals vertical index error in a total station?

Answer: Face-left and face-right zenith angles that do not sum to 360°

Without index error, direct and reverse zenith angles to the same point sum to exactly 360°.