Accuracy Check of the Measuring Tool

The following tasks should be performed only by well-trained and qualified persons. The legalities with regard to performing an accuracy check or calibration of a measuring tool must be known.

The largest influence is exerted by the ambient temperature. In particular, temperature differences that occur from the ground upwards can refract the laser beam.

In order to minimise thermal influences resulting from heat rising from the floor, it is recommended that you use the measuring tool on a tripod. In addition, position the measuring tool in the centre of the work surface, wherever this is possible.

In addition to external influences, device-specific influences (e.g. falls or heavy impacts) can also lead to deviations. For this reason, check the levelling accuracy each time before beginning work.

If the measuring tool exceeds the maximum deviation for the measuring procedures described below, perform a calibration see Calibrating the measuring tool or have the measuring tool checked by a Bosch customer service agent.

For a reliable and precise result, it is recommended that you check the levelling accuracy on a free measuring distance of 30 m on firm ground in front of a wall. Carry out a complete measuring procedure for each of the two axes.

  • Mount the measuring tool in a horizontal position 30 m from the wall on a tripod, or place it on a firm, level surface. Switch on the measuring tool.
  • Once levelling is complete, mark the centre of the laser beam on the wall (point Ⅰ).
  • Turn the measuring tool 180° without adjusting the height. Allow it to level in and mark the centre point of the laser beam on the wall (point Ⅱ). Ensure that point Ⅱ is vertically over or under point Ⅰ.

Repeat the measuring process for the other axis. To do this, turn the measuring tool by 90° before beginning the measurement.

The maximum permitted deviation on the 30 m measuring distance is as follows: ±1.5 mm. The discrepancy d between points Ⅰ and Ⅱ must therefore amount to no more than 3 mm for each of the two measuring processes.

For this check, you will need a free measuring distance on firm ground in front of a 10-metre tall wall. Fix a plumb line to the wall.

  • Position the measuring tool in the vertical position on a firm, level surface. Switch the measuring tool on and allow it to level in.
  • Set up the measuring tool so that the laser beam meets the plumb line at the exact centre of the upper end. The discrepancy d between the laser beam and the plumb line at the lower end of the line reveals the measuring tool's deviation from the vertical.

For a 10 m high measuring distance, the maximum permitted deviation is as follows: ±1 mm. The discrepancy d must therefore be no more than 1 mm.