How to Clean and Maintain a Total Station

Applies to: Topcon GT-1000 series, Trimble S-series, Leica TS-series, Sokkia CX-series

A total station is a precision optical and electronic instrument that spends its working life in construction environments — dust, mud, rain, vibration, and temperature extremes. Regular cleaning and maintenance extends instrument life, maintains measurement accuracy, and prevents small problems from becoming expensive repairs. Most of what a field crew can do is external maintenance — lens cleaning, hardware checks, and proper storage. Factory service handles the internal adjustments that require a controlled environment and calibration tools.

Daily After-Session Care

After every session, before returning the instrument to its case: remove visible dirt and mud from the instrument exterior with a dry brush or compressed air. Pay attention to the footscrews on the tribrach — construction site grit works into the threads and degrades smooth leveling motion over time. Wipe down the footscrews and tribrach plate with a slightly damp cloth, then dry. Replace the objective lens cap and the eyepiece cap. Do not store the instrument in its case while wet — condensation damages the optical system. Allow it to dry at room temperature before casing.

Check the instrument for impact damage: examine the objective lens for chips or cracks, look for bent or loose handles, and confirm the tribrach locking mechanism operates smoothly. Any impact hard enough to leave a mark on the case should trigger a calibration check before the next session — dropped instruments should be verified with a two-peg test (for horizontal accuracy) and a collimation check before being returned to production use.

Cleaning the Optical Surfaces

The most damage that field crews do to total stations is optical surface scratching from improper lens cleaning. Never use a paper towel, shop rag, or dry cloth on a lens surface — all of these scratch the anti-reflection coating. The correct procedure: first use a lens blower (a rubber bulb blower, not compressed air from a can — propellant residue contaminates lenses) to remove loose particles. Then, if further cleaning is needed, use a lens-grade microfiber cloth or lens tissue moistened with optical-grade lens cleaner. Wipe with light circular motion from center to edge.

The objective lens (front lens) can be cleaned as above. The eyepiece can be cleaned the same way. The laser plummet window (on the bottom of most modern instruments) should be cleaned whenever mud or dust accumulates — an obscured plummet window causes centering errors. On Leica TS instruments, the EDM (distance measuring) window on the telescope body should also be kept clean — dirt on the EDM window causes weak or erratic distance measurements.

Tribrach and Mounting Hardware Maintenance

The tribrach is the adapter between the tripod and the instrument. Tribrachs require occasional maintenance: the three footscrews should move smoothly throughout their full travel range. If footscrews are stiff, clean the threads with a soft brush, apply a small amount of the manufacturer-recommended grease (do not over-grease — excess lubricant attracts dust), and work the screw through full travel to distribute. If the optical plummet in the tribrach (on tribrachs so equipped) is foggy or misaligned, it needs cleaning or factory adjustment.

The instrument mounting lock (the lever that locks the total station to the tribrach) should hold the instrument firmly with no play. If the instrument rocks at all on the tribrach, the lock mechanism needs adjustment or the tribrach locking plate is worn — either requires bench work. Do not use a total station that is loose on the tribrach; any play introduces measurement error and risks the instrument falling.

Monthly Field Checks

Monthly maintenance for instruments in daily use: (1) perform the two-peg test to verify horizontal plane accuracy — see performing a two-peg test; (2) check the plate and circular level vials — see checking level vials; (3) verify the horizontal and vertical collimation by the face-left/face-right double measurement method described in the instrument's manual; (4) confirm the laser plummet is centered and clean.

Document these checks with dates and results. Tracking calibration over time reveals patterns — an instrument whose collimation drifts quickly likely has a loose internal component and needs service before it fails on a critical job.

Factory Service Intervals

Send total stations to an authorized service center annually for instruments in full-time daily use. Every two years is appropriate for instruments used occasionally. Factory service includes cleaning of internal optical surfaces (not accessible in the field), full angular and distance calibration, servo drive inspection on robotic instruments, and battery contact cleaning. The typical cost for Topcon GT series: $200-400. Trimble S-series: $250-450. Leica TS: $250-500. Service cost versus the cost of a failed layout session or re-work from a poorly calibrated instrument — it is almost always worth it.