# Accuracy Check and Calibration of the Measuring Tool

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

To obtain permanently accurate results, carry out a calibration at least once a year or have the measuring tool checked by a Bosch customer service agent.

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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 in the levelling accuracy check, perform a calibration or have the measuring tool checked by a Bosch customer service agent.

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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.

1. Mount the measuring tool in a horizontal position 30 m from the wall on a tripod, or place it on a firm, level surface.
2. Switch on the measuring tool.

1. Once levelling is complete, mark the centre of the laser beam on the wall (point Ⅰ).

1. Turn the measuring tool 180° without adjusting the height.
2. Allow the measuring tool to level in.
3. Mark the centre of the laser point on the wall (point Ⅱ).

Ensure that point Ⅱ is vertically over or under point Ⅰ.

4. Rotate the measuring tool by 90° and repeat the measuring process for the other axis.

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.

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

1. Fix a plumb line to the wall.
2. Position the measuring tool in the vertical position on a firm, level surface.
3. Switch the measuring tool on and allow it to level in.
4. Set up the measuring tool so that the laser beam meets the plumb line at the exact centre of the upper end.
5. 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.

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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.

- Perform calibration of the measuring tool with extreme precision or have the measuring tool checked by a Bosch customer service agent. Inaccurate calibration leads to incorrect measuring results.

- Only start the calibration if you have to perform a calibration of the measuring tool. As soon as the measuring tool is in calibration mode, you must perform the calibration meticulously to the end in order to ensure that no incorrect measuring results are produced afterwards.

- Check the levelling accuracy after every calibration . If the deviation is outside the maximum permitted limits, have the measuring tool checked by a Bosch- customer service agent.

### X-axis and Y-axis Calibration

The GRL 600 CHV can only be calibrated using the LR 60 laser receiver, and the GRL 650 CHVG can only be calibrated using the LR 65 G. The laser receiver must be connected to the measuring tool via Bluetooth® see Establishing a connection to the remote control/laser receiver.

The positions of the measuring tool and laser receiver cannot be changed during calibration (with the exception of the alignments or rotations described). Therefore position the measuring tool on a firm, level surface and secure the laser receiver.

Calibration should be performed via the Bosch Levelling Remote App if possible. There is less likelihood of error when controlling the tool via the app. Otherwise, the measuring tool's position can be altered if buttons are pressed without due care.
For calibration without the app, the corresponding buttons on the measuring tool must be pressed. It is not possible to use the remote control during calibration.

A free measuring distance of 30 m on a firm surface is required. If no such measuring distance is possible, calibration can also be performed with lower levelling accuracy on a measuring distance of 15 m.

## To mount the measuring tool and the laser receiver for calibration:

1. Mount the measuring tool in the horizontal position 30 m or 15 m from the laser receiver on the tripod (43) or position it on a firm, level surface.
2. Secure the laser receiver at the correct height:

- Either to a wall or to another surface by means of magnets or the suspension hooks on the laser receiver,
- or to a securely fastened aid with the holder for the laser receiver.

see Attaching Using the Holder

## Aligning the measuring tool for calibration:

1. Align the measuring tool so that the X-axis indicator imprinted on the measuring tool with the "+" side is pointing to the laser receiver. For this, the X‑axis must be perpendicular to the laser receiver.

## To start calibration:

Calibration via the Bosch Levelling Remote App:

1. Switch on the measuring tool.
2. Start calibration in the app.
3. Follow the instructions in the app.

Calibration without the app:

1. Switch on the measuring tool and laser receiver.
2. Make sure that both of these are connected via Bluetooth®.
3. Press the button on the laser receiver and the button on the laser receiver simultaneously to start the calibration.
4. "CAL" will appear on the display of the laser receiver.
5. Press and hold the button on the laser receiver to cancel the calibration, if required.

## To perform calibration without the app:

1. In the menu that appears in the measuring tool display after starting calibration, select the existing distance between the measuring tool and the laser receiver.
2. Press the or button.
3. Confirm your selection with by pressing the button.

1. To confirm the selected measuring distance including the corresponding levelling accuracy (), press the button.
2. To go back to selecting the measuring distance (), press the button.

1. Align the height of the laser receiver so that the variable laser beam (8) on the laser receiver is indicated as "centred". see Direction indicators
2. Secure the laser receiver at this height.

## Calibration of the X-axis:

1. Check whether the measuring tool and laser receiver are aligned with each other, as illustrated on the display (the "+" side of the X-axis is aligned to the laser receiver).
2. Start calibration of the X-axis with by pressing the button.

1. If this step appears on the display, rotate the measuring tool 180° so that the "–" side of the X‑axis is directed at the laser receiver.

For each rotation, take care not to change the height and slope of the measuring tool.

1. Confirm the rotation with by pressing the button.
2. Calibration of the X-axis continues.

This symbol will appear on the measuring tool display if the X-axis has been successfully calibrated.

1. Continue calibration with by pressing the button.

## Calibration of the Y-axis:

1. Rotate the measuring tool 90° in the direction of the arrow so that the "+" side of the Y‑axis is directed at the laser receiver.
2. Confirm the rotation with by pressing the button.

1. If this step appears on the display, rotate the measuring tool 180° so that the "–" side of the Y‑axis is directed at the laser receiver.
2. Confirm the rotation with by pressing the button.
3. Calibration of the Y-axis continues.

This symbol will appear on the measuring tool display if the Y-axis has been successfully calibrated.

1. End the calibration of the Y-axis with by pressing the button.

This symbol confirms that the X-axis and the Y-axis have been successfully calibrated with the levelling accuracy selected at the beginning.

1. End the calibration with by pressing the button.

If the calibration has been completed successfully, the measuring tool then automatically switches itself off.

## Calibration failed:

The relevant error message will appear in the measuring tool display if calibration of the X‑axis or the Y‑axis has not been successful. "ERR" will appear on the display of the laser receiver.

1. Cancel the calibration with by pressing the button.
2. Make sure that the measuring tool and the laser receiver are aligned correctly (see description above).
3. Restart the calibration.

If calibration fails again, have the measuring tool checked by a Bosch customer service agent.

### Z-axis calibration

A free measuring distance on firm ground in front of a 10 m wall is required for the calibration.

1. Fix a plumb line to the wall.
2. Position the measuring tool on a firm, level surface.
3. Switch the measuring tool on and allow it to level in.
4. Align the measuring tool so that the laser beam is perpendicular to the wall and cuts through the plumb line.
5. Switch the measuring tool off.
6. Press and hold the button and then also press the button.
7. The measuring tool is switched on.
8. Allow the measuring tool to level in.

1. Align the laser beam so that it runs as parallel as possible to the plumb line.

1. Tilt the laser beam in the ◀ direction by pressing the button. Tilt the laser beam in the ▶ direction by pressing the button.
2. If it is not possible to align the laser beam in parallel to the plumb line, align the measuring tool to the wall more precisely and start the calibration process again.
3. If the laser beam is aligned in parallel, save the calibration with by pressing the button.

This symbol confirms that the Z-axis has been calibrated successfully. At the same time, the status indicator (12) will flash green 3 times.

1. End the calibration with by pressing the button.

1. If the calibration has been completed successfully, the measuring tool then automatically switches itself off.

This error message will appear if calibration of the Z-axis has been unsuccessful.

1. Cancel the calibration with by pressing the button.
2. Ensure that the reference vertical line is in the pivoting range of the rotation head and restart the calibration.

Make sure that the measuring tool is not moved during calibration.

If calibration fails again, have the measuring tool checked by a Bosch customer service agent.