For construction machinery load moment indicator, the selection of a weight sensor must consider factors such as the equipment type, load scenario (static/dynamic), accuracy requirements, and environmental adaptability. The following is an analysis of common sensor types and their applicable scenarios:
I. Classification by Principle and Applicable Scenario
1. Strain Gauge Load Cell
Principle: A strain gauge senses the deformation of an elastic body under load and converts the weight signal into an electrical signal.
Advantages: High accuracy (0.1%-0.5% FS), meeting the core measurement requirements of torque limiters;
Wide measuring range (10kg-1000t), adaptable to construction machinery of varying tonnages;
Affordable cost, strong stability, and good vibration resistance.
Disadvantages: Not suitable for high-frequency dynamic weighing and requires proper sealing (IP67/IP68).
2. Piezoelectric Sensor
Principle: Utilizes the generation of an electric charge by a piezoelectric crystal under load, making it suitable for dynamic force measurement.
Advantages: Fast response speed (microseconds), suitable for high-frequency dynamic weighing (such as transient impact during lifting);
Compact size, suitable for integration in confined spaces (such as at the joint of a telescopic arm).
Disadvantages: Zero-point drift, unsuitable for long-term static weighing; requires a charge amplifier, resulting in high cost.
3. Capacitive Sensor
Principle: Indirectly measures weight by changing the capacitance value through changes in the spacing between the electrodes.
Advantages: Strong anti-interference ability (unaffected by temperature and magnetic fields);
Resistant to harsh environments (high temperatures and corrosive environments).
Disadvantages: Slightly lower accuracy (0.5%-1% FS) and smaller measuring range (typically <50 tons), limiting its application in large equipment.
4. Hydraulic Sensor
Principle: Infers weight by measuring changes in hydraulic system pressure (using Pascal’s law).
Advantages: Rugged construction, strong shock and overload resistance;
Can be directly integrated into hydraulic pipelines, suitable for hydraulically driven construction machinery.
Disadvantages: Accuracy is affected by hydraulic oil temperature and viscosity (with an error of approximately 1%-2% FS), requiring regular calibration.
II. Key Selection Criteria
Capacity Matching: The sensor’s capacity must be 1.2-1.5 times the actual maximum load (allowing for a safety margin). For example, a load cell for a 50t crane might have a capacity of 60-80t.
Accuracy Level:Load Moment Indicator is safety device, and sensor accuracy is recommended to be ≥0.5% FS (static) or ≥1% FS (dynamic) to avoid overload risks due to measurement errors.
III. Typical Equipment Selection Examples
| Construction Machinery Type | Force Characteristics | Recommended Sensor Type | Core Requirements |
| Truck Crane | Dynamic liftingHigh vibration | Strain gauge type (IP67) | 0.3% FS accuracy100g shock resistance |
| 塔式起重机 | Primarily staticHigh-altitude environment | Strain gauge type (corrosion-resistant) | 5-50t rangeExcellent low-temperature stability |
| Hydraulic Excavator | Transient shock loadsHydraulic drive | Hydraulic/piezoelectric type | 200% overload resistanceResponse speed <1ms |
| Mining Loader | Excessive dustFrequent heavy loads | Capacitive/hydraulic type | IP68 protection10-30t range |
SeeZol Technology comprehensively considers various aspects of construction machinery, construction environment, accuracy requirements, and budget. Our various load moment indicators can be paired with different weight sensors to meet diverse customer needs. This ensures accurate and stable weight monitoring within the load moment Indicator, providing key data support for the safe operation of construction machinery.
