Bosch GLM 50-23 G Professional Laser Measure

Robert Bosch Power Tools GmbH, 70538 Stuttgart, GERMANY

www.bosch-pt.com

Introduction

This manual provides instructions for the safe and reliable operation of the Bosch GLM 50-23 G Professional laser measure. It covers features, operation, safety precautions, and technical specifications.

Product Overview

The GLM 50-23 G Professional is a digital laser measure designed for measuring distances, lengths, heights, spacings, and inclinations, as well as for calculating areas and volumes. It is suitable for indoor use.

Key Components:

(1) Memory key [★]
(2) Function key [Func]
(3) Minus key / Left key [-]
(4) Display
(5) Measure key [▲]
(6) Plus key / Right key [+]
(7) Basic settings key [★]
(8) Power switch / Return key [3]
(9) Lanyard loop
(10) Laser warning label
(11) Serial number
(12) Battery compartment cover latch
(13) Battery compartment cover
(14) 1/4" tripod thread
(15) Receiver lens
(16) Laser beam outlet
(17) Belt clip
(18) Belt clip screw
(19) Laser target plate
(20) Laser viewing glasses
(21) Tripod
(22) Lanyard
(23) Protective bag

Safety Precautions

Read all instructions carefully before operating the measuring instrument.
Do not stare into the laser beam or the reflected laser beam. Do not point the laser beam at people or animals.
If the laser beam enters the eye, consciously close the eye and move the head away from the beam.
Do not modify the laser device.
Laser viewing glasses (accessory) are not to be used as protective eyewear or sunglasses.
Only qualified specialists should repair the measuring instrument using original spare parts.
Keep children away from the laser measuring instrument.
Do not use the measuring instrument in potentially explosive atmospheres (e.g., in the presence of flammable liquids, gases, or dust).
Ensure the laser warning label remains legible.

Operation

Turning On/Off

To turn on the measuring instrument and laser, briefly press the measure key (5) [▲].
To turn on the measuring instrument without the laser, briefly press the power switch/return key (8) [3].
To turn off the measuring instrument, press and hold the power switch/return key (8) [3].

Measurement Functions

The instrument defaults to length measurement upon first startup. Subsequent startups will default to the last used measurement function.

To select a different measurement function, press the function key (2) [Func]. Use the plus/right key (6) [+] or minus/left key (3) [-] to select the desired function, and press the function key (2) [Func] or measure key (5) [▲] to activate it.

Length Measurement

Select length measurement. Briefly press the measure key (5) [▲] to activate the laser. Briefly press the measure key (5) [▲] again to perform the measurement. The result will appear at the bottom of the display.

Continuous Measurement:

In continuous measurement mode, the instrument can be moved relative to the target. The measurement value is updated every 0.5 seconds.

Min/Max: Continuously displays the minimum or maximum measured value.
Large Font: Displays the measured value in a larger font for better readability.
Measuring Tape: Displays the distance from the measurement marker. The reference is not the edge of the instrument.

Briefly press the measure key (5) [▲] to interrupt continuous measurement. The current measurement value is displayed at the bottom of the display. Pressing the measure key (5) [▲] again will restart continuous measurement.

Continuous measurement automatically switches off after 4 minutes.

Area Measurement

Select area measurement. Measure width and length sequentially, similar to length measurement. The laser beam remains active between measurements. The line segment being measured flashes in the area measurement display.

The first measurement value is displayed at the top of the display. After two measurements, the area is automatically calculated and displayed at the bottom of the display.

Volume Measurement

Select volume measurement. Measure width, length, and depth sequentially, similar to length measurement. The laser beam remains active during the three measurements. The line segment being measured flashes in the volume measurement display.

After the third measurement step, the instrument automatically calculates and displays the volume. The final result is displayed at the bottom of the display.

Indirect Distance Measurement

Indirect distance measurement offers three measurement functions to determine different line segments.

Indirect Height Measurement (See Figure G):

Select indirect height measurement. Ensure the measuring instrument is at the same height as the lower measurement point. Tilt the measuring instrument around the reference plane and measure line segment "1" (displayed in red on the screen).

After measurement, the result for the calculated line segment "X" is displayed in the result line (d). The measurement values for line segment "1" and angle "α" are located in the measurement value line (c).

Double Indirect Height Measurement (See Figure H):

The measuring instrument can indirectly measure all line segments on a plane perpendicular to the instrument.

Select double indirect height measurement. Measure line segments "1" and "2" in the same sequence as length measurement.

After measurement, the result for the calculated line segment "X" is displayed in the result line (d). The measurement values for line segments "1", "2", and angle "α" are located in the measurement value line (c).

Indirect Length Measurement (See Figure I):

Select indirect length measurement. Ensure the measuring instrument is at the same height as the measurement point. Tilt the measuring instrument around the reference plane and measure line segment "1" as in length measurement.

Wall Area Measurement (See Figure J)

Wall area measurement is used to calculate the total area of several walls with the same height but different lengths.

Select wall area measurement. Measure the height of the space, similar to length measurement. The measurement value is displayed in the upper measurement value line. The laser remains active.

Then measure the length of the first wall, L₁. The area is automatically calculated and displayed in the result line (d). The last measured length value is displayed in the lower measurement value line (c). The laser remains active.

Now measure the length of the second wall, L₂. The measurement value in the measurement value line (c) is added to the length L₁. The sum of the two lengths (displayed in the middle measurement value line (c)) is multiplied by the stored height H. The total area is displayed in the result line (d).

You can measure any number of additional lengths Lx, which will be added automatically and then multiplied by the height H. The prerequisite for indirect area calculation is that the first measured length (in this case, the height of the space) is the same for all sub-areas.

Stakeout Function (See Figure K)

The stakeout function measures a defined length repeatedly. These lengths can be transferred to a surface, for example, to cut workpieces to the same length or to build dry-wall constructions. The adjustable minimum length is 0.1 m, and the maximum length is 50 m.

Note: In the stakeout function, the distance to the marker is displayed on the screen. The reference is not the edge of the instrument.

Select the stakeout function. Use the plus/right key (6) [+] or minus/left key (3) [-] to set the desired length. Press the measure key (5) [▲] to start the stakeout function and slowly move away from the starting point.

The measuring instrument continuously measures the distance to the starting point. The defined length and the current measurement value are displayed. Arrows at the bottom or top indicate the minimum distance to the next or previous marker.

The coefficient on the left indicates how many times the defined length has been reached. The green measurement value indicates a length that has reached a marker. If the reference value exceeds the display, the blue measurement value indicates the actual value.

Incline Measurement / Digital Level

Select incline measurement / digital level. The instrument automatically switches between the two modes.

The digital level is used to check the horizontal or vertical alignment of a target (e.g., washing machine, refrigerator). If the incline exceeds 3 degrees, the sphere in the display turns red.

Incline measurement is used to measure slopes or inclines (e.g., stairs, railings, when fitting furniture, or laying pipes). The left side of the measuring instrument serves as the reference surface for incline measurement.

Stored Values Display

The value of each measurement or the final result is automatically stored.

Up to 30 values (measured values or final results) can be displayed.

Select the storage function []. The upper part of the display shows the number of the stored value, the lower part shows the corresponding stored value, and the left side shows the corresponding measurement function.

Press the plus/right key (6) [+] to scroll forward through the stored values. Press the minus/left key (3) [-] to scroll backward through the stored values.

The earliest value is in memory position 1, the latest in position 30 (when all 30 storage spaces are occupied). When another value is stored, the earliest value is always deleted.

Deleting Stored Values

To delete a specific stored value, select the value (see "Stored Values Display", page 23). First, press the power switch/return key (8) [3], then confirm with the function key (2) [Func].

To delete all stored values, press the basic settings key (7) [*], select the function, then press the plus/right key (6) [+] and confirm with the function key (2) [Func].

Add/Subtract Values

Measured values or final results can be added or subtracted.

Adding Values

The following example describes adding areas:

Determine the area according to the chapter "Area Measurement" (see "Area Measurement", page 20).

Press the plus/right key (6) [+]. The calculated area and the "+" symbol are displayed.

Press the measure key (5) [▲] to start the next area measurement. After the second measurement according to the chapter "Area Measurement" (see "Area Measurement", page 20), the second area measurement result is displayed at the bottom of the screen. To display the final result, press the measure key (5) [▲] again.

Note: For length measurements, the final result is displayed immediately.

To exit the addition calculation, press the function key (2) [Func].

Subtracting Values

To perform a numerical subtraction, press the minus/left key (3) [-]. Subsequent operations are similar to adding values.

Deleting Measured Values

Briefly press the power switch/return key (8) [3] to delete the last measured value in all measurement functions. Repeatedly pressing the power switch/return key (8) [3] briefly will delete measured values in reverse order.

Work Tips

General Instructions

Do not cover the receiver lens (15) and the laser beam outlet (16) during measurement.
Do not move the measuring instrument during measurement (exception: continuous measurement function and incline measurement). Place the measuring instrument on a fixed support surface or base as much as possible.

Factors Affecting Measurement Range

The measurement range depends on the ambient lighting conditions and the reflectivity of the target surface. In case of strong ambient light, use the laser viewing glasses (20) (accessory) and the laser target plate (19) (accessory), or shade the target surface to better see the laser beam.

Factors Affecting Measurement Results

Errors in measurement are unavoidable on different surfaces due to physical principles. For example:

Transparent surfaces (e.g., glass, water)
Reflective surfaces (e.g., polished metal, glass)
Porous surfaces (e.g., insulating materials)
Textured surfaces (e.g., rough plaster walls, natural stone)

Use the laser target plate (19) (accessory) on these surfaces if necessary. Incorrect aiming at the target point can also lead to incorrect measurements.

Additionally, air layers with temperature differences and indirect reflections can affect the measurement values.

Incline Measurement Accuracy Check and Calibration (See Figure L)

Periodically check the accuracy of the incline measurement. This can be done by a comparative measurement. Place the measuring instrument on a flat surface and measure the incline. Rotate the measuring instrument by 180° and measure the incline again. The difference between the displayed values should not exceed 0.3°.

If there are larger deviations, the measuring instrument must be recalibrated. Select this in the settings and follow the instructions on the display.

After significant temperature changes and after collisions, it is recommended to check the accuracy and recalibrate the measuring instrument if necessary. After a temperature change, wait for the measuring instrument to stabilize before calibrating.

Distance Measurement Accuracy Check

You can check the accuracy of the measuring instrument as follows:

Select a precisely known, constant measurement distance, approximately 3 to 10 meters (e.g., room width, doorway). The measurement should be taken under good conditions, i.e., indoors and with a smooth, reflective target surface.
Perform 10 continuous measurements of the distance.

Under good conditions, the deviation between a single measurement and the average value over the entire measurement distance should be a maximum of ±4 mm. Keep a measurement log for future reference to check the instrument's accuracy.

Using the Tripod (Accessory)

A tripod is particularly useful for longer distances. Mount the measuring instrument using the 1/4" thread (14) onto a tripod (21) or the quick-release plate of a commercially available camera tripod. Tighten the fixing screw of the quick-release plate. Adjust the measurement reference plane in the settings (see "Selecting the Reference Plane (See Figure A)", page 18).

Using the Belt Clip (Accessory) (See Figure M)

The belt clip (17) allows you to conveniently hang the measuring instrument on your belt.

Troubleshooting

If measurements cannot be performed correctly, the "Error" message will appear on the display. Restart the measurement.

The measuring instrument continuously monitors its functions. If a malfunction is detected, the display will only show the icon next to the text, and the measuring instrument will automatically switch off. In this case, please return the measuring instrument to your dealer for service by Bosch customer service.

Maintenance and Service

Maintenance and Cleaning

Keep the measuring instrument clean at all times.
Do not immerse the instrument in water or other liquids.
Wipe off dirt from the instrument using a damp, soft cloth. Do not use any cleaning agents or solvents.
Handle the receiver lens (15) with the same care as you would a pair of glasses or a camera lens.
If the instrument is damaged or requires servicing, send the measuring instrument to an authorized Bosch customer service center.

Customer Service and Application Advice

The Bosch customer service department answers questions regarding repair, maintenance, and spare parts for Bosch products. Exploded views and information on spare parts can also be found at: www.bosch-pt.com

The Bosch application advice team is happy to help with any questions regarding Bosch products and their accessories.

When ordering spare parts or inquiring about them, always provide the 10-digit item number from the machine's type plate.

China Mainland

Bosch Power Tools (China) Co., Ltd.

No. 567 Bin Kang Road, Binjiang District

Hangzhou, Zhejiang Province, China

Disposal

Dispose of the measuring instrument, batteries/rechargeable batteries, accessories, and packaging in an environmentally friendly manner.

Do not dispose of the measuring instrument or batteries/rechargeable batteries in household waste.

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