Correction Of The Ruler Length

- Aug 10, 2018-

There are three factors affecting the measuring precision of steel tape, such as temperature, the tension of the ruler band and the error caused by the gravity of the ruler band when the measure is suspended in mid-air.

The error correction methods caused by these three factors are as follows:

1, temperature

Prerequisite: No error at 20 ℃ temperature.

Formula: Due to temperature error = Actual measured value x-ruler with expansion coefficient x (using temperature -20℃)

such as: a steel tape expansion coefficient of 0.0000115, at 10 ℃ temperature of 36m correction: 36000mmx0.0000115x (10-20) =-4.14mm

2, the length of the belt tension Prerequisite: The ruler belt does not need the tension correction in the standard tension condition.

Scaling occurs when the ruler band exceeds or falls below the standard tension.

Formula: Error caused by tension = (actual measurement of tension-standard tension) x measured distance (telescopic elastic force) X-Ruler section area)

such as: Standard tension 50N, 100N tension under 36m when the correction: (100-50) X36000mm÷ (205800x2.52) =3.47mm

3. The error caused by the weight of the ruler belt when it is suspended in mid-air for measuring

Formula: The error caused by the gravity of the ruler =-{(measured distance with unit weight x) x measured distance}÷ (24x measured tension)

For example, 100N, 36m

-{(0.000194x36000mm) x36000mm}÷ (24x measured tension) =-7.32mm

Different specifications of the steel tape to correct the parameters are different.