In the era of deep integration of Industry 4.0 and smart logistics, electronic belt scales, as core equipment for continuous bulk material measurement, have become the "industrial scales" for industries such as coal, mining, ports, and cement. From precise loading on 10,000-ton mobile ship loaders to efficient unloading with truck unloaders and full-process monitoring via belt conveyors, the dynamic weighing accuracy of belt scales directly impacts enterprise cost accounting, trade settlement, and production efficiency. However, complex operating conditions—such as high dust, strong vibrations, temperature/humidity fluctuations—as well as equipment factors like belt tension changes and sensor drift, constantly threaten measurement system stability. Statistics show that improperly maintained belt scales can exhibit annual errors exceeding 5%, leading to direct economic losses reaching millions of dollars.

Daily Maintenance Standards

Environmental Protection & Equipment Management

1. Protection Standards for Conveyors and Weighing Zones

   • Indoor equipment: Prioritize enclosed facilities to avoid weather and dust interference.
   • Outdoor scenarios (e.g., port mobile ship loaders, mining truck unloaders):
     
     • Install weatherproof shelters covering ≥12m before/after the weighing zone, with height ≥1.7m (from conveyor frame base).
     • Use 304 stainless steel frames in coastal areas for salt spray resistance.
   • Temperature/humidity control: Maintain -10°C~40°C in equipment rooms with ≤85% relative humidity (install dehumidifiers).

2. Scale Frame System Maintenance

   • Cleaning procedures:
     
     • Power off after shutdown; clean accumulated material in weighing zones using high-pressure air guns (focus on levers, idlers, and speed measurement rollers).
     • For sticky materials (e.g., wet coal), use soft brushes with anhydrous ethanol.
   • Idler maintenance:
     
     • Lubrication intervals: Every 3 months for heavy-duty applications (Mobil XHP222 grease), 6 months for light-duty.
     • Replacement criteria: Replace immediately if radial runout >0.5mm or axial movement >1mm.
   • Anti-deviation measures:
     
     • Empty belt deviation: Install V-shaped aligning idlers (35° angle) 2m outside the weighing zone.
     • Material bias: Adjust deflector plates at truck unloader discharge points for central material flow.

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17A/B Belt Scale Balancing Technical Specifications

1. Imbalance Diagnosis

   • Symptoms:
     
     • Output difference >1mV between sensors (measured unloaded).
     • Cumulative value fluctuation >±0.3%/hour (trade settlement scenarios).
   • Common causes:
     
     • Ship loader scale frame deformation due to wave impacts.
     • Loose sensor rods from frequent truck unloader start/stop cycles.

2. Balancing Procedure

   1. Power off the indicator; disconnect sensor signal cables (retain excitation wires).
   2. Measure sensor outputs (0-30mV range) with a multimeter after power-up.
   3. Example: Sensor A=12.5mV, Sensor B=13.8mV → 1.3mV difference requires adjustment.
   4. Loosen Sensor B's rod locknut; rotate counterclockwise 1/4 turn (≈0.5mV change per full turn).
   5. Recheck until voltage difference <0.1mV; tighten nuts and mark against loosening.
   6. Re-zero and perform chain code calibration verification.

Note: Monitor zero stability for 8 continuous hours post-adjustment.

For inquiries about belt scale maintenance and calibration, contact us:

• Zoomry Heavy Industry Official Website
• +86 131-6401-6717
• oversea@zoomry.cn

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Weighing Instrument Maintenance Essentials

1. Hardware Maintenance

   • Cleaning:
     
     • Housing: Use microfiber cloth with 75% medical alcohol; avoid organic solvents.
     • Internal: Clean quarterly with 0.3MPa compressed air (maintain >20cm distance from PCBs).
   • Wiring inspection:
     
     • Signal cable shield grounding resistance <1Ω; bending radius >5×cable diameter.
     • Connector contact resistance <0.1Ω (measured with Fluke 287).

2. Anti-Interference Configuration

   • Install TDK ZCAT3035-1330 filters on power inputs to suppress high-frequency harmonics.
   • Use twisted-pair shielded cables (AWG22, ≥85% shield coverage) for signal lines.

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Lightning Protection System Design

Three-Stage Protection Scheme

Level	Equipment	Installation Position
Primary	OBO V25-B/3+NPE	Main power cabinet entrance
Secondary	Phoenix Contact FLT-PS24	Instrument power input
Tertiary	Weidmuller UR20-485	Sensor signal line entrance

Grounding Requirements

• Independent ground rod: Galvanized angle steel L50×5×2500mm, buried >0.8m deep.
• Ground resistance: <2Ω in humid areas, <4Ω in dry areas (document measured values).

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Full Calibration Process

Zero Calibration Standards

1. Zeroing Procedure

   • Auto-zero (e.g., 2105 instrument):MainMenu→Calibration→ZeroCalibration→Start→Confirmafter countdown
   • Key parameters:
     
     • Test cycles: Integer belt revolutions (typically 3, verified via encoder pulses).
     • Resolution boost: Automatic 10× resolution increase (e.g., 0.1kg→0.01kg).
   • Manual zeroing scenarios:
     
     • Zero loss after mainboard replacement (requires backup parameter input).
     • Factory reset after cold start (code: FACTORY_RESET).

2. Zero Cumulative Value Calculation

   • Formula: Q max×t×allowed error rate = maximum allowable cumulative value
   • Example: (200,000kg/h ÷60)×3×0.05% = 5kg

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II. Calibration Methods

1. Material Calibration Standards

   • Minimum test load:
     
     • Take the higher value between:
       
       • Max flow rate×1 hour×2%
       • Single revolution load (L=belt length, v=speed, Q=flow):
         Single revolution load = Q×L ÷3.6v
   • Operational restrictions:
     
     • Prohibit calibration at wind speeds >Level 5 (close hatches on ship loaders).
     • Re-sample if material moisture variation >2%.

2. Chain Code Calibration

   Belt Width (mm)	Recommended Chain Code (kg/m)
   500-800	10-15
   800-1200	20-25
   1200-2000	30-40

   • Error correction formula: New interval = Original interval×(Theoretical value ÷ Displayed value)
   • Example: Theoretical=2.858t, Displayed=2.901t, Original interval=1200 → 1200×(2858÷2901)=1182

3. Hanging Weight Verification

   • Procedure:
     
     • Record calibration constant K (kg/pulse) after material calibration.
     • Hang G=50kg, run t=5 minutes, record pulse count N.
     • Error verification: Error = |G-(N×K)÷G|×100% ≤0.5%

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Data Management & Spare Parts System

Critical Parameter Archiving

Instrument Parameter Backup List

Parameter	Example Value	Storage Method
Belt Length	158.6m	CSV + physical labels
Test Cycles	3 revolutions	Encrypted database storage
Zero Value	12548	Cloud server auto-sync

Calibration Record Template

Date	Cal Type	Standard (t)	Display (t)	Error (%)	Operator
2023-08-15	Chain	2.858	2.901	+1.50	Zhang San

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Spare Parts Inventory Strategy

Core Spares List

Category	Model	Min Stock	Applicable Equipment
Weighing Instrument	SYDL2105	2 units	Ship loaders/Truck unloaders
Load Cell	HBB-10T	4 units	Belt conveyors
Speed Sensor	PLR-12R (1024P/R)	2 sets	Port handling systems

Spare Parts Testing Standards

• Sensors: Zero output <1mV; insulation resistance >5000MΩ (500V DC megohmmeter test).
• Instruments: No ERR codes during self-test; AD sampling fluctuation <3 digits (24-hour burn-in).

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Through systematic maintenance and precise calibration, belt scale measurement errors in complex scenarios like mobile ship loaders and truck unloaders can be controlled within 0.25%. Enterprises are advised to implement digital maintenance platforms integrating belt scale data with MES/ERP systems, achieving closed-loop management from equipment upkeep to trade settlement.