Practical Guide to Industrial Platform Scale Calibration

Recently updated on July 31st, 2025 at 05:41 am

What is Platform Calibration?

Platform calibration is the core maintenance technology for industrial weighing systems. It establishes an accurate mapping relationship between physical weight and sensor electrical signals by applying standardized weights with known mass. This process essentially “re-scales” the weighing instrument—prolonged heavy loading or drastic temperature changes cause microscopic deformation in the strain gauge’s metal elastomer, leading to false “zero drift” when unloaded (e.g., 0.15% baseline error from residual preload) and “linear distortion” at full capacity (a 50-ton scale may deviate by 47kg at the 30-ton range). Calibration engineers restore accuracy through three critical operations: zero calibrationeliminates residual errors from the scale’s self-weight; span adjustment modifies the AD converter gain coefficient to ensure 20kg weights display as 20.00kg rather than 19.83kg; and corner balance calibration resolves regional weighing discrepancies caused by mechanical deformation using a nine-point test, such as a 3-meter-wide platform underreporting weight by 5% in the front-left corner versus the rear-right. This is not merely numerical correction but a profound realignment of the sensor-indicator-mechanical structure trinity.

Why is Regular Calibration Essential?

Regular calibration is both a legal mandate and quality safeguard for industrial scales. GB/T 7723 mandates that Class III trade scales permit only ±50g error per 50kg capacity. Exceeding this incurs daily fines exceeding 10,000; in 2019, a port was fined 2.3 million for commercial fraud due to a 0.3% error on an uncalibrated 80-ton truck scale. Qualitatively, hidden accuracy erosion acts as insidious poison: A chemical plant suffered 0.48% negative deviation on its raw material receiving scale after six months without calibration, losing 120 tons of high-purity ethylene annually (value >1 million). More critically, calibration data exposes latent failures—when sensor output drift consistently exceeds >0.02mV/V, it often signals junction box moisture ingress or elastomer metal fatigue. A 2022 warehouse collapse investigation revealed that inaccurate weighing failed to warn of structural overload. Each calibration fortifies the foundation of operational safety and commercial integrity.

Core Value of Calibration

Regular calibration is the lifeline for precise industrial weighing. As scales endure frequent use, internal sensors gradually deviate, while temperature fluctuations and mechanical vibrations subtly degrade accuracy. Calibration transcends numerical adjustment—it represents a solemn commitment to measurement reliability, particularly for trade settlement scales where legal compliance and commercial reputation hinge on precision. Recognizing that every calibration reinforces product quality and transactional fairness is the fundamental responsibility of every operator.

（Here is a calibration video of our Stainless Steel Tube Platform Scale TYG Series for reference）

Standardized Calibration Procedure for Industrial Platform Scales

Step 1: Pre-Calibration System Preparation

Cleaning and Leveling Protocol
Wipe the platform with fiber-free cloths and pH-neutral cleaner, focusing on removing mineral dust and oil residue from gaps. Support sensor cables during cleaning to prevent crushing, maintaining >5cm bend radius. Adjust leveling feet using a dual-axis spirit level until bubbles stabilize centrally. Manually shake the platform to check stability (pass standard: ≤3mm depression at corners).
Critical Note: After cleaning, wait 30 minutes for the scale to reach ambient temperature. Steam-cleaned IP68-rated scales require 1 additional hour for drainage.

Environmental Stability Control
Deactivate fans and hydraulic equipment within 10 meters. Test ground vibration by standing a coin vertically (must remain upright for 1 minute). Temperature fluctuation must not exceed 2°C during calibration—place a recorder on the platform for real-time monitoring. Set gravity compensation by entering local acceleration codes in the indicator menu . Apply additional coefficients for elevations >500m.

Step 2: Internal Auto-Calibration

For scales with self-calibration function

• Enter calibration mode: Long press “CAL” for 3s until “CAL0” appears

• Wait for automatic zero stabilization (“——” becomes 0.00)

• Load certified weights: Place at platform center (recommended: 50% capacity)

  Use forklift with slow descent; place anti-slip rubber under weights

• Complete calibration: Enter actual weight value (e.g., 5000kg)

  Press confirm when “SAVE” flashes to store parameters

• Error handling: “Err 05” indicates weight value deviation—reverify weight certification

Step 3: External Manual Calibration

Requires service engineers

• Sensor Zero Calibration: Remove all loads, short-circuit EXC± terminals, measure mV/V output with multimeter (pass range: -0.01~+0.01mV/V)

• Linearity Correction: Apply weights incrementally (10%/30%/50%/100% capacity), record deviations at each step, adjust AD gain via potentiometer
  Case Study: A logistics center reduced 5-ton weighing error from 32kg to 1.2kg by correcting 50% point deviation

• Corner Balance Calibration: Mark nine-grid test points on platform, test each with 20% capacity weights, adjust sensor output coefficients via junction box

Service Provider Value

• Diagnose hidden faults: Sensor creep, junction box moisture

• Issue legal calibration certificates: ISO/IEC 17025 compliant

• Extended services: Historical database for component lifespan prediction

Golden Rules for Daily Maintenance

Scheduled maintenance outweighs post-failure repairs. Perform monthly four-point tests and quarterly full calibrations. Strictly observe safe load limits—internal sensor damage from dropped heavy objects is often invisible. Install dust covers in gritty environments; use stainless steel scales in corrosive workshops. Preserve calibration logs not just for audits: historical data becomes your most effective diagnostic tool when accuracy drifts.

Environmental Interference Countermeasures

Temperature is the stealthiest accuracy killer. If workshop day-night differentials exceed 10°C, perform zero calibration during shift changes. Install metal conduits for signal cables in high-EMI areas; use vibration-damping pads under scales. For persistent reading fluctuations, power off nearby equipment to identify interference sources. Critical reminder: Newly installed frequency converters often cause instability.

FAQ

Q: Causes of inaccuracy post-calibration?

• Debris trapped under platform

• Expired test weights

• Crushed sensor cables

• Electromagnetic interference from nearby equipment

Q: How to troubleshoot non-zero display?

1. Clean dust from sensor connectors

2. Adjust limit bolts for 1mm clearance

3. Test sensor impedance with multimeter (normal: ~350Ω)
   If unresolved, circuit board leakage from moisture may be the cause

Q: Weight class for general workshops?
M1-class weights suffice for 0.1% accuracy scales. Prioritize periodic recertification and prevent rust/impact damage.

Q: Calibrate newly installed scales immediately?
Yes. Transport vibrations cause initial errors. Perform three-point calibration:

1. Zero unloaded scale

2. Correct linearity with 20% capacity weight

3. Verify with 60% capacity weight
   Recalibrate after 24 hours of use.

Q: Mitigating humidity effects in rainy seasons?

• Place desiccant silica gel in junction boxes

• Execute quick zero calibration daily before operations

• For severe humidity, use indicators with automatic moisture compensation