1. Essential 3-step operation method for beginners 
Calibration benchmark: Establishing a solid foundation for accuracy 
First, place the base of the height gauge steadily on the calibrated marble measuring platform (the flatness error of the platform should be ≤ 0.005mm/m to avoid introducing initial errors due to the unevenness of the platform). Then, slowly move the column and let the measuring head gently touch the surface of the platform. At this time, pay attention to observing the display values on the screen. Press the "zero reset" key for a long time until the reading shows 0. If it is a mechanical height gauge, rotate the differential cylinder to align the zero mark of the main scale with that of the secondary scale, and ensure the calibration is correct before starting the measurement. 
② Select the measurement points: Choose the right probe + Control the force appropriately 
Based on the shape of the measured object and the measurement requirements, select the appropriate probe: flat probe (the material is mostly hard alloy, suitable for measuring flat metal surfaces and plastic parts), pointed probe (the needle tip diameter is usually ≤ 0.5mm, suitable for measuring narrow areas such as the bottom of grooves and edge of steps), spherical probe (used for measuring arc surfaces and spherical surfaces, to avoid the probe scratching the surface of the workpiece). 
When moving the column, it is necessary to do so at a constant and slow speed to avoid the probe colliding with the workpiece due to rapid movement. When the probe approaches the highest point of the object to be measured, switch to the fine-tuning mode and let the probe gently touch the surface of the workpiece. The force should be appropriate, that is, "the probe is slightly compressed and the workpiece does not move". If the force is too large, it may cause the workpiece to deform or damage the probe. If the force is too small, it may result in inaccurate contact and the reading deviation can be more than 0.003mm. 
③ Reading data: Digital display and mechanical models each have their own techniques 
The digital display type height gauge is easy to operate. Once the display value stabilizes (usually taking 1-2 seconds to avoid fluctuations caused by vibration), you can directly read the value. Additionally, by pressing the "UNIT" key, you can switch between mm (millimeters) and in (inches) units in one click, meeting the needs of different scenarios. 
The height rule for mechanical models needs to be combined with the readings of the main scale and the secondary scale: First, read the integer part on the main scale (look at the scale on the left side of the zero mark on the secondary scale), then read the decimal part on the secondary scale (find the line where the secondary scale aligns with the scale on the main scale, and the corresponding secondary scale mark is the decimal), and the final value = main scale integer + secondary scale decimal. For example, the reading on the main scale is 25mm, the 16th line on the secondary scale aligns with the main scale, and the secondary scale accuracy is 0.001mm, then the total reading is 25.016mm. 
II. Applicable Scenarios and Efficiency Advantages 
The height gauge is widely used in various fields such as mechanical processing, electronic manufacturing, and mold production: In the mold industry, it is used to measure the depth of the mold cavity and the step difference of the parting surface to ensure the mold's closing accuracy; in the electronics industry, it is used to measure the height of components on the PCB board to avoid assembly interference caused by overly high components; in the production of automotive parts, it is used to measure the flatness of the engine cylinder block to ensure the sealing performance. 
Compared with traditional calipers, the measurement efficiency of the height gauge has been significantly enhanced - when measuring a batch of parts of the same specification, only one calibration of the reference is required. Subsequent measurements only need to repeat the "positioning - reading" steps. The measurement time for a single part is reduced from 30 seconds of the caliper to within 10 seconds, with an efficiency increase of over 3 times. At the same time, it avoids the human error caused by multiple measurements with the caliper. 
III. Common Error Avoidance Techniques 
Environmental temperature influence: The metal components of the height gauge will expand and contract due to temperature changes. If the temperature difference between the measurement environment and the calibration environment exceeds 5℃, the instrument should be placed in the measurement environment for more than 30 minutes until the temperature stabilizes before it can be used. Otherwise, an error of 0.002mm/℃ may occur. 
2. Probe wear: Regularly check the wear condition of the probe. If scratches or deformations appear on the surface of the probe, it should be replaced immediately; otherwise, it will lead to an increase in measurement errors. 
Workpiece cleaning: Before measurement, use a lint-free cloth to dip in alcohol and wipe the surface of the workpiece to remove oil stains, dust, and other impurities. Avoid allowing the impurities to lift the probe, which may affect the accuracy of the reading.