EN 12077-2:2008 Load Capacity Indicator Safety Rules
EN 12077-2:2008 — Safety Requirements for Load Capacity Indicators — specifies an accuracy of +/-5%, early warning at 90%, alarm at 100%, automatic shutdown at 105%, and self-test requirements. It is the European standard for overload limiters.
Technical Requirements
EN 12077-2 is consistent with ISO 10245-2. The indicator system comprises a lifting capacity limiter, a load moment limiter, and a display unit. Accuracy is within +/-5%. An early warning sounds at 90% of rated load, a visual and audible alarm activates at 100%, and at 105% the system cuts power to the hoisting and luffing circuits (while still permitting lowering and derricking motions). A self-test routine runs at startup to verify the sensors and display system. Sensors are rated IP65 for outdoor service. Kelude equips its cranes with load capacity indicators according to the standard, with calibration every six months to ensure accuracy remains within the +/-5% range.
Key Parameters
The load capacity indicator is one of the most critical safety devices on a crane. Its three-stage alarm mechanism gives the operator ample warning before an overload condition develops: an early warning at 90% alerts the operator that the rated load capacity is being approached; an alarm at 100% requires loading to stop immediately; and automatic shutdown at 105% forcibly cuts power to prevent overload accidents.
| Setpoint | Action |
|---|---|
| early warning | 90%– Audible and Visual Indication |
| Alarm | 100%– Buzzer and Red Lamp |
| Stop | 105%– Cut-off Hoisting / Lifting Increment Power Supply |
| Self-check | Automatic at Startup |
Inspection & Calibration
Calibrate every six months. If the deviation exceeds +/-5%, adjustment is required. Check sensor wiring connections and protective covers monthly. Verify the audible and visual alarm function on the display unit during the annual inspection.
| Inspection | Content |
|---|---|
| Sensor | Monthly Inspection |
| Display Unit | Per Annual Inspection Monthly Inspection |
| Calibration | Semi-annually |
FAQ: Load Capacity Indicator Requirements & Maintenance
Q: What are the accuracy and set-point requirements for the load capacity indicator under EN 12077-2?
A: Accuracy is ±5%. An early warning is triggered at 90% of rated load with an audible and visual alarm. At 100%, a continuous alarm sounds with a flashing red light and hoisting is automatically stopped. At 105%, the hoisting/lifting power supply is cut off (lowering remains available). The system performs a self-check automatically at startup.
Q: What is the calibration interval and what maintenance is required?
A: Calibration must be performed at least every six months. If a deviation greater than ±5% is detected, the system must be readjusted. The Load Sensor should be inspected monthly for cable connections and protection status. The display unit requires an annual inspection of the text display and the audible and visual alarm functions.
Q: How does Kelude configure its load capacity indicators?
A: Kelude Heavy Industry supplies load capacity indicators in compliance with EN 12077-2, featuring ±5% accuracy and a three-stage alarm system (90% / 100% / 105%), with calibration required every six months. The Load Sensor is rated IP65, making it suitable for outdoor environments. This configuration is standard on all cranes exported to Europe.
Q: What protection rating is required for the sensor?
A: The Load Sensor has a protection rating of IP65, providing effective dustproofing and Water Jet Proof protection against rain and dust in outdoor crane working environments. The sensor's signal cable uses shielded twisted pair cable to reduce electromagnetic interference and ensure stable signal transmission.
