Introduction to Level Error Checking
In surveying, ensuring the accuracy of leveling equipment is essential. Performing level error checks on auto-level or leveling machines helps achieve precise results. Follow this simple step-by-step procedure to minimize potential discrepancies.
Step 1: Set Up the Level Machine
Begin by setting up your level machine correctly. Make sure it is well-leveled on firm ground. Stability is critical to avoid incorrect readings. Always double-check that the setup follows manufacturer guidelines.
Step 2: Position Staff at Equal Distances
Next, place two staff members 20 meters away from the station on opposite sides. This symmetrical setup ensures balanced readings from both targets.
Step 3: Record Initial Staff Readings from Station A
With the equipment ready at Station A, take staff readings from both Target 1 and Target 2. Record these values carefully.
Example Reading at Station A
| STATION A | Target 1 | Target 2 | Difference (T1 – T2) |
|---|---|---|---|
| For example | 120.00 cm | 186.20 cm | -66.20 cm (120.00 – 186.20) |
Calculate the difference between Target 1 and Target 2 readings. This initial value will be essential for cross-checking accuracy later.
Step 4: Shift to Station B for Verification
Move the level machine to Station B, located approximately 5 meters from one target. Maintain the total distance of 40 meters between the two staff members.
Step 5: Record Staff Readings from Station B
Take new readings from both targets at Station B. Accuracy is key during this phase.
Example Reading at Station B
| STATION B | Target 1 | Target 2 | Difference (T1 – T2) |
|---|---|---|---|
| For example | 117.7 cm | 183.90 cm | -66.20 cm (117.7 – 183.90) |
Again, calculate the difference between the two readings.
Step 6: Analyze the Level Error
Finally, the level error is determined by comparing the differences between Station A and Station B.
Formula:
Difference at Station A – Difference at Station B
= (-66.20) – (-66.20) = 0
A result of zero indicates no error. However, minor 2-3 mm discrepancies are acceptable depending on project precision.
Acceptable Error Margin
An error tolerance of 2-3 mm is generally considered acceptable. However, this range may vary based on specific project requirements or industry standards.
Click Here To See Brief Overview Of Levelling
