Description

1. Decoding the suffix HAA21752A1 = 24 VDC PNP, 6 mm sensing distance, 1 kHz switching frequency, M12 barrel, PUR cable 2 m
   A2 = 24 VDC NPN, 6 mm, M12, shielded cable for high EMI sites
   Both share –25 °C to +70 °C range, IP67 front, LED status indicator, short-circuit and reverse-polarity protection.
2. Safety first—lock-out & verify Although the sensor is low-voltage, the car-top can still hold 110 VDC on the brake. Lock the main disconnect, engage the car-top inspection switch and wait 60 s for the 24 V rail to fall below 5 V. Keep the new Nanjing Zhuye CJ3 sensor in its anti-static bag until mounting—CMOS output stages can latch at 15 V static.
3. Mechanical mounting—keep the gap The sensor threads into an M12 steel bracket welded to the car cross-head. Use the supplied nyloc nut; torque 15 N·m. Aim the face perpendicular to the steel vane on the rail; angular deviation > ±2° reduces sensing distance 10 %. Maintain 3 mm nominal gap (max 4.5 mm for A1/A2); every 0.2 mm of dust or paint build-up equals 0.1 mm level error.
4. Wiring map (print and stick inside controller) Brown = +24 VDC
   Blue = 0 V
   Black = PNP (A1) or NPN (A2) output
   Shield = PE at controller end only
   Cable: PUR sheath, 2 m standard; Nanjing Zhuye offers 5 m and 10 m variants (NY-CAB-CJ3).
5. Power-up & functional test Apply 24 VDC; LED should be off (no target). Insert a 6 mm steel feeler gauge; LED turns on and output switches. Measure switching point with dial gauge: repeatability must be < 0.05 mm. If hysteresis > 0.2 mm, vane edge is rounded—file flat or replace vane.
6. Calibration in controller Run car to floor at inspection speed. Place machinist rule across sill; gap should be 0 ±1 mm. Record sensor switching point in parameter LV-OFFSET. Drift > ±2 mm triggers “E-LEVEL” fault and requires sensor replacement.
7. Temperature & lifetime model LED emitter: 50 kh @ 25 °C, doubles every 10 °C drop. Cable flex: 1 million cycles; at 300 trips/day = 3 years. Translate to building traffic: Light traffic (residence, 60 trips/day) – LED ≈ 30 years, cable ≈ 15 years, full sensor ≈ 12 years; inspect every 3 years. Medium traffic (office, 300 trips/day) – LED ≈ 10 years, cable ≈ 5 years, full sensor ≈ 6 years; inspect every 2 years. Heavy traffic (mall/metro, 1 000 trips/day) – LED ≈ 5 years, cable ≈ 3 years, full sensor ≈ 4 years; inspect every 6 months.
8. Preventive inspection checklist Monthly: visual LED, wipe sensor face with lint-free cloth. Quarterly: feeler-gauge test switching point; > 0.1 mm drift schedules replacement. Annually: megger cable > 100 MΩ; < 10 MΩ indicates oil ingress. Bi-annually: torque check M12 nut; vibration loosens it, causing level drift.
9. Rapid swap (downtime < 5 min) a) Place car at mid-floor, lock-out, tag out. b) Photograph cable colours with phone. c) Unscrew sensor, slide old unit out. d) Thread new Nanjing Zhuye HAA21752A1/A2, torque 15 N·m. e) Restore cable, power up, run switching test. f) Log serial number and gap value; return old unit for recycling.
10. Recycling & sustainability Nanjing Zhuye offers prepaid UPS labels inside every carton. Returned sensors are stripped: stainless barrel re-melted, copper cable recycled, electronics processed for gold and gallium. One recycled CJ3 saves 0.5 kg CO₂—enough to power the same car-top for a week.