KONE Elevator Leveling Sensor 77U, 77N, 77S: Precision Layer Positioning for Safe & Smooth Operation

Proper Usage Methods of KONE Elevator Leveling Sensor 77U, 77N, 77S

1. Installation & Collaborative Calibration

• First, cut off the elevator power supply and ensure safety. Thoroughly clean the installation positions on the elevator car frame (corresponding to upper, middle, and lower leveling points) to remove dust, oil stains, and debris, ensuring a stable and flat mounting base for the sensors.
• Fix the three sensors firmly using matching bolts and nuts according to KONE’s standard installation positions: 77U is installed at the upper leveling position of the car, 77N at the standard leveling position (aligned with the floor), and 77S at the lower leveling position. The induction surfaces of the three sensors should be aligned with the magnetic strip installed on the guide rail, with a horizontal gap of 3–5mm (standard range). The tightening torque of the bolts should comply with KONE’s technical requirements (typically 8–12 N·m) to avoid loosening due to elevator vibration.
• Correctly connect the wiring: According to the wiring diagram provided by Nanjing Zhuye Elevatorparts and KONE, connect the signal wires and power wires of 77U, 77N, 77S to the corresponding terminals of the KONE elevator main controller respectively. Use shielded wires for signal transmission to reduce electromagnetic interference. Ensure wiring is tight and the insulation layer is intact; clearly mark the sensor models on the wires to avoid confusion and ensure accurate signal matching.
• Post-installation collaborative calibration and test run: Restore the elevator power supply, operate the elevator in inspection mode, and calibrate the three sensors collaboratively. Verify that 77U is triggered first when the car approaches the floor from above, 77N is triggered at the standard leveling position (car floor aligned with the floor), and 77S is triggered when approaching from below. Confirm that the elevator can stop stably at the floor under the joint action of the three sensors, with no overshoot or undershoot (leveling error ≤2mm). If there is a positioning deviation, adjust the installation height of the corresponding sensor in time.

2. Daily Operation & Routine Inspection

• During elevator operation, monitor the leveling status of the elevator at each floor. If the elevator stops with obvious deviation (exceeding 3mm), frequent overshoot/undershoot, door opening delay, or door opening failure at the non-leveling position, it may indicate a failure or signal abnormality of one or more sensors among 77U, 77N, 77S.
• Conduct weekly visual inspections: After cutting off the power supply, check the appearance of 77U, 77N, 77S for damage, including cracks or deformation of the metal shell, looseness of bolts and wiring terminals, and damage or aging of wires. Retighten loose fasteners in a timely manner, clean the induction surfaces of the three sensors and the matching magnetic strip with a dry, lint-free cloth, and replace damaged wiring if necessary.
• Regularly check the signal stability through the KONE elevator control system’s diagnostic function. Detect the signal output of 77U, 77N, 77S respectively to ensure they are triggered accurately and respond in a timely manner during the elevator’s lifting process. If there is signal loss, delayed response, or false triggering, trace the cause (such as loose wiring, poor contact, or magnetic strip damage) and resolve it immediately.

3. Regular Maintenance

• Every 3 months, thoroughly inspect the installation positions and gaps with the magnetic strip of the three sensors. Adjust immediately if there is deviation due to elevator vibration or structural deformation; at the same time, check the integrity of the magnetic strip and replace it if there is damage or demagnetization.
• Every 6 months, conduct a comprehensive cleaning of the three sensors and the magnetic strip. For sensors installed in harsh environments (high humidity, high dust, strong electromagnetic interference), increase the cleaning frequency. Avoid using water, alcohol, or corrosive cleaners that may damage the sensor’s shell and internal components.
• Annually, conduct a professional performance test: Use precision instruments to detect the positioning accuracy, signal response time, and anti-interference ability of 77U, 77N, 77S respectively. If the performance indicators do not meet KONE’s technical requirements, contact Nanjing Zhuye Elevatorparts for professional maintenance or replacement with original KONE sensors to ensure the consistent safety performance of the elevator’s leveling system.

Recommended Replacement Cycle of KONE Elevator Leveling Sensor 77U, 77N, 77S

1. Standard Replacement Cycle

2. Scenario-Based Cycle Adjustment

• Harsh Operating Environments: For elevators operating in high-humidity coastal regions, high-dust construction sites, high-temperature unventilated machine rooms, or areas with strong electromagnetic interference, the replacement cycle should be shortened to 3–4 years. Harsh conditions accelerate the aging of internal electronic components, corrosion of the shell, and degradation of magnetic induction performance, reducing the sensors’ reliability and collaborative accuracy.
• Low-Frequency Use Scenarios: For elevators with low usage frequency (e.g., villa elevators, small office buildings with less than 3,000 monthly operations) and stable operating environments, the replacement cycle can be appropriately extended to 6–8 years after a professional inspection by Nanjing Zhuye Elevatorparts confirms that the three sensors’ positioning accuracy, signal stability, and structural integrity are intact.

3. Immediate Replacement Conditions

• The sensor’s metal shell is severely cracked, deformed, or corroded, losing its protective function and affecting normal operation.
• The elevator has frequent leveling errors (exceeding 5mm) that cannot be eliminated by calibration, and the fault is confirmed to be caused by one or more sensor failures among 77U, 77N, 77S.
• One or more sensors have unstable signal output, missing signals, or delayed responses, leading to elevator door opening failure, delayed door opening, or incorrect stop position that cannot be resolved by maintenance.
• The sensors fail the annual performance test, and the performance indicators cannot be restored to the standard range even after maintenance.