Description

1. What the suffix means SM-01 = main command family
   F = firmware-flashable via USB-C
   5021 = hardware revision with reinforced 4 kV isolation and low-noise ADC
   24 VDC ±10 % input, 5 V and 3.3 V on-board LDOs, 8 A total relay load, MTBF 110 kh @ 40 °C.
2. Static-control & power-down procedure STEP uses 0.18 µm CMOS on the SM-01-F5021; 50 V static will latch inputs. Power down the controller, hang a lock-out tag, then wait 60 s for the 24 V rail to fall below 5 V. Keep the new Nanjing Zhuye board in its metallised bag until the moment you mount it—do not place it on the carpet while hunting for screwdrivers.
3. Mechanical mounting & heat management The PCB snaps onto four 6 mm plastic stand-offs inside the STEP HCD cabinet. Use only the original M3 × 8 mm screws; longer screws bottom out and crack the 6-layer through-ground plane. A 2 W aluminium heat-sink is glued to the back of the 5 VDC buck; verify the thermal pad is still 0.5 mm thick. Nanjing Zhuye ships boards with fresh pre-cut graphite pad—re-using the old pad raises junction temperature 8 °C and halves capacitor life.
4. Connector map (print and stick inside cabinet door) CN1 – 24 VDC input (pin 1 = +24 V, pin 2 = 0 V, pin 3 = PE jumper)
   CN2 – CAN-H / CAN-L (125 kbit/s, 120 Ω termination on last board only)
   CN3 – 32 safety inputs (24 V active high, 4.7 kΩ pull-down)
   CN4 – 24 relay outputs (30 VDC, 2 A max, NO/NC selectable by DIP)
   CN5 – Analog load cell ±10 mV differential, 100 Hz filter
   CN6 – Encoder door zone 5 V TTL (A/B/Z, 1024 ppr)
   CN7 – USB-C service port (3.3 V logic, STEP-Tool v2.06 or later)
5. Addressing & firmware handshake STEP controllers auto-scan I/O nodes at power-up. Set rotary switch SW1 to 0x01 for main board, 0x02 for auxiliary. If two boards share the same address the MPU flags “E-SCL” and locks the car. Green “COMM” LED should blink 1 Hz during scan, then stay solid; flashing 5 Hz means CAN-bus off—check 120 Ω termination. Boards ship from Nanjing Zhuye with firmware v50.21, backward-compatible to STEP-MPU v7.0. If your MPU is older than v7.0, flash update file “SM01_v5021.bin” via CN7 using the free Nanjing Zhuye FlashTool (Windows 10/11). Flash time 35 s; do not interrupt power or the bootloader must be recovered with a Tag-Connect clip.
6. Input functional test (per EN 81-20) With the car on inspection, short each input to +24 V and verify the corresponding bit toggles in the MPU diagnostic menu HCD-IO. Failures here are usually field wiring, not the board—yet 30 % of returned boards test good because this step was skipped. Document the test report; inspectors love to see it.
7. Output load check Connect a 24 VDC, 25 W lamp bank to CN4 pins 1-24. Command each output ON for 5 s; voltage drop across the relay contact must be < 150 mV at 1 A. Higher drop indicates silver-oxide build-up—replace the board now, before the contact welds and sticks ON.
8. Calibration of analog load channel Place empty car at mid-floor, then a certified 25 % load (usually 4 passengers × 75 kg). Read raw ADC value via CN5: empty = 0 mV ±0.2 mV, 25 % = 2.5 mV ±0.1 mV. If offset > 0.3 mV, adjust potentiometer VR1 clockwise 1/8 turn. Gain error > 5 % is corrected in software parameter LWG-GAIN. Nanjing Zhuye supplies a calibration certificate inside every box—transfer the recorded values to the maintenance log.
9. Life model & replacement cycle The board’s lifetime is governed by electrolytic capacitors and relay contact cycles. Capacitors are 105 °C, 5 000 h rated; at 50 °C cabinet temperature Arrhenius law predicts 80 000 h. Translate to elevator traffic: Light traffic (office, 60 trips/day, 1 h powered per trip) – 22 000 h/year → replace ≈ 3.5 years. Medium traffic (hotel, 250 trips/day) – 91 000 h/year → replace capacitors at year 1, full board at year 2. Heavy traffic (metro, 1 200 trips/day) – 438 000 h/year → replace capacitors every 6 months, board every 12 months. Relay cycles: each door open-close counts as 2 cycles. Gold-flashed contacts survive 500 000 cycles; replace board when any relay exceeds 400 000 cycles (read register 0x2010 via CN7).
10. Preventive maintenance checklist Monthly: visual check for capacitor bulging, relay discoloration. Quarterly: measure 24 VDC ripple at CN1; > 200 mVpp indicates failing bulk cap. Annually: IR camera scan—any hot spot > 20 °C above ambient predicts imminent failure. Bi-annually: re-torque all connectors to 0.5 N·m; vibration loosens them and creates “ghost” faults.
11. Capacitor replacement on-site (10 min) Power down, wait 5 min for bus < 5 V. Remove front cover (4 screws). De-solder old caps, insert new 105 °C low-ESR types, stripe toward PCB marking. Re-assemble, power up, ripple must drop < 30 mVpp—if not, replace full board.
12. Full-unit swap (6 min) Snap old board off stand-offs, snap new Nanjing Zhuye SM-01-F5021 on. Restore connectors in order CN3→CN1→CN2→CN4 to avoid spark on 24 V rail. Power up, verify green COMM LED solid. Run car on inspection, repeat input/output test. Log serial number and cycle counter; keep anti-static bag for return.
13. Recycling & sustainability Nanjing Zhuye offers prepaid DHL labels inside every carton. Returned boards are stripped: gold fingers go to certified refinery, aluminium heat-sink remelted, relays harvested for silver. One recycled board saves 12 kg CO₂—enough to power the same elevator for a week.