Shengtai Instruments ST128 Dual-Mode Electronic Test Weight Meter for Corn (GB/T 5498–2023 Compliant)

Overview

The Shengtai Instruments ST128 Dual-Mode Electronic Test Weight Meter is engineered to comply with the latest Chinese national standard for corn—GB/T 5498–2023—and serves as a precision instrument for determining the test weight (also known as bulk density or volumetric mass) of cereal grains. Unlike conventional single-mode testers, the ST128 supports both standardized volumetric displacement and direct gravimetric measurement protocols, enabling accurate assessment across heterogeneous grain types without manual recalibration. Its core methodology follows the principle of fixed-volume weighing: a pre-calibrated 1000 mL cylinder is filled under controlled conditions (free-fall from a defined height, standardized tapping, and surface leveling), after which the mass of the contained sample is measured using a high-stability load cell integrated into a microprocessor-controlled platform. This approach ensures traceable, repeatable results aligned with internationally recognized grain quality evaluation frameworks—including ISO 7971-1:2017 (Cereals — Determination of bulk density — Part 1: Gravimetric method) and AOAC Official Method 986.19.

Key Features

• Microprocessor-based control system with real-time error diagnostics and auto-zero compensation
• Dual-mode operation: configurable for large-particle grains (e.g., maize/corn) and small-particle grains (e.g., wheat, sorghum, millet, barley) via selectable cylinder fill algorithms
• High-contrast red LED display (7-segment, 4-digit) for ambient-light robustness in laboratory and field environments
• Integrated RS-232 serial interface compliant with EIA/TIA-232 standards for bidirectional communication with Windows-based PCs
• Optional thermal line printer support (via parallel port or USB-to-serial adapter) for GLP-compliant hardcopy record generation
• Stainless-steel measuring cylinder with certified volume tolerance of ±1.5 mL at 20 °C, calibrated per ISO/IEC 17025-accredited procedures
• Low-power design (10 W nominal) suitable for continuous operation in QA/QC labs with stable AC mains supply (220 V, 50 Hz)

Sample Compatibility & Compliance

The ST128 is validated for use with intact, dry, unprocessed cereal grains meeting moisture content specifications outlined in GB 1353–2018 (Corn) and GB 1351–2008 (Wheat). It accommodates particle size distributions ranging from 1.8 mm (millet) to 9.5 mm (dent corn), with built-in firmware compensation for inter-granular void fraction variability. All mechanical and electronic components conform to GB/T 2829–2002 (Periodic inspection of periodically inspected products) and meet EMC requirements per GB/T 18268.1–2010 (Measurement, control and laboratory equipment – EMC requirements). The instrument supports audit-ready documentation workflows required under China’s Grain Quality Supervision and Inspection System (GQIS), and its measurement uncertainty profile has been verified against NIM (National Institute of Metrology, China) reference standards.

Software & Data Management

When connected to a host PC running Shengtai’s proprietary ST-DataLink v3.2 software (Windows 10/11 compatible), the ST128 enables full data traceability: timestamped measurements, operator ID logging, instrument serial number embedding, and automatic CSV export. The software enforces user-level access controls (administrator/operator modes), supports electronic signature capture, and generates audit trails compliant with GB/T 22239–2019 (Information Security Technology – Basic Requirements for Cybersecurity Level Protection). For regulated environments, optional 21 CFR Part 11 add-on modules provide electronic record authentication, change history tracking, and digital certificate integration—facilitating alignment with GMP/GLP quality systems in grain trading, feed formulation, and state reserve management facilities.

Applications

• Official grain grading and classification per national commodity standards (e.g., GB 1353–2018, GB/T 20570–2015)
• Incoming raw material inspection at flour mills, ethanol plants, and animal feed manufacturers
• Research applications in agronomy and post-harvest physiology laboratories evaluating varietal density traits
• Calibration verification of portable test weight meters used in grain elevators and procurement centers
• Supporting FAO/WFP food security assessments through harmonized bulk density reporting

FAQ

Does the ST128 require annual calibration certification?
Yes. While factory-calibrated prior to shipment, users must perform routine verification using certified reference weights (Class M2, per OIML R111) at least once per quarter. Full recalibration by an accredited metrology lab is recommended annually or after any physical impact event.

Can the ST128 be used for oilseeds or processed grains (e.g., cracked corn)?
No. The instrument is validated exclusively for whole, unbroken kernels meeting the size and shape criteria defined in GB/T 5498–2023. Oilseeds, flaked, rolled, or milled products fall outside its scope of accreditation.

Is firmware upgrade support available remotely?
Yes. Firmware updates are distributed via secure HTTPS download through Shengtai’s authorized service portal. Updates include enhanced grain-type libraries, improved temperature drift compensation, and expanded compliance reporting templates.

What is the warranty coverage for load cell replacement?
The integrated load cell is covered under the standard 12-month limited warranty. Extended coverage (up to 36 months) is available under Shengtai’s Premium Service Agreement, including on-site verification and metrological revalidation.