T/HBJLXH 005-2022 Active

Main technical content: 1. **Calibration conditions**: - Temperature: (20 ± 5) °C; - Humidity: ≤85% RH. - Calibration equipment: - Leveling blocks: - Large blocks (125–500 mm): 8 pieces; - Large blocks (600–1000 mm): 5 pieces. 2. **Preparation before calibration**: - The standard instrument and height measuring device should be in the same room and equilibrated at temperature for at least 0.5 hours. After turning on the electronic height measuring device, preheat it according to the manufacturer's specifications (if no preheating time is specified, the preheating time should be at least 15 minutes). Before measurement, adjust the height measuring device so that the working surface of its base is essentially horizontal. Then, calibrate the display error. During measurement, the base of the height measuring device should not be moved. The external structure of the height measuring device should be intact, with no mechanical damage or deformation. All parts should interact smoothly and reliably, and the digital display or scale should not have any defects that hinder reading. The instrument should function normally. Instruments with self-calibration functions should be able to perform self-calibration normally. 3. **Calibration of display error**: - Select at least 5 height values within the measurement range of the height measuring device for calibration. Use a dedicated clamp to combine the length dimensions of the leveling blocks. Place the leveling blocks or the combined block set on the working surface of the height measuring device base. Measure the center length dimensions of the block set three times. Take the average value of the three measurements as the measured value. Subtract the actual size of the leveling blocks from the measured value to obtain the display error at that point. Calculate the display error at the measurement points of the height measuring device according to Formula (1). 4. **Ca