- Provisions on Verification Cycle: According to the "Metrology Law of the People's Republic of China" and the "Metrological Verification Regulations for Non-automatic Weighing Instruments" (JJG 539-2016):
- Commercial Weighing Instruments (for trade settlement): Verified once every six months to ensure the accuracy of weighing data and compliance with overseas trade metrological regulations (such as the EU Measuring Instruments Directive MID), avoiding customer claims caused by accuracy issues.
- Industrial Weighing Instruments (for production management): Verified once a year to meet the internal production management needs of enterprises and ensure the accuracy of inventory and consumption data, adapting to the quality management systems of overseas factories (such as ISO 9001).
- Special Scenarios (such as explosion-proof and high-temperature environments): The verification cycle can be shortened to 3-6 months according to the equipment usage frequency and accuracy change; weighbridges in harsh overseas environments such as chemical industry and mines need to increase the verification frequency to ensure safety and accuracy.
- Selection of Verification Agencies:
- Official Agencies: Local metrology testing institutes (institutes), which are legal metrology agencies, and the verification results have legal effect; such as the National Metrology Institute (NMI) in the EU and the National Institute of Standards and Technology (NIST)-recognized agencies in the United States, which can provide English verification certificates for overseas trade and compliance audits.
- Verification Process:
- Make an Appointment in Advance: Contact the verification agency 1-2 weeks in advance to determine the verification time and location (overseas customers need to provide detailed addresses and contact information, and communicate in English); inform the weighbridge model, capacity, and usage scenario to facilitate the agency's preparation of standard weights and equipment.
- Equipment Preparation: Clean the weighbridge to ensure its appearance is intact and functions are normal (such as normal instrument display and no sensor failures), prepare the equipment manual (English version) and the previous verification certificate (if any) to facilitate the verifier's understanding of the equipment.
- On-site Verification: Verifiers use standard weights (such as 100kg and 200kg, complying with OIML standards) to conduct loading tests, calibrate the accuracy (error ≤ 0.1%), and record data (English record forms); the test content includes zero calibration, linear error test, repeatability test, etc.
- Issue Certificate: After passing the verification, the "Metrological Verification Certificate" (English version, including the verification agency's qualification, equipment information, and error data) is issued; if it fails, rectification (such as adjusting the corner error of the junction box and replacing sensors) is required before re-verification until it passes.
- Certificate Storage: The verification certificate should be properly kept for enterprise annual inspections, trade dispute evidence, and overseas customer audits (such as ISO certification audits); it is recommended to scan and archive (English electronic version) for easy remote submission of audit materials.
