Description

1. Pre-installation safety & ESD protocol
   Power down the controller, lock-tag the main breaker and wait 60 s for the 24 VDC rail to fall below 5 V. The board uses CMOS latches vulnerable to 30 V static; keep it in the metallised bag until mounted. Ground your wrist strap to the controller PE bar—not the door sheet metal—to avoid ground loops that ghost segments.
2. Physical mounting
   DCA26800CR-A5 snaps onto 4 × 6 mm plastic stand-offs inside the COP or LOP can. Verify stand-off height: 15 mm for 9 mm acrylic, 18 mm for 12 mm glass. Wrong height creates parallax shadows and “bleeding” digits. Use only the original M3 × 8 mm screws; longer screws bottom out and crack the 4-layer PCB. Torque to 0.4 N·m—over-tightening warps the board and opens micro-vias.
3. Connector map (print and tape inside can)
   J1 – 24 VDC input (pin 1 = +24 V, pin 2 = 0 V, pin 3 = chassis GND)
   J2 – RS-485 A/B (9600 baud, 8-N-1) address set by DIP 1-4
   J3 – Segment output (34-pin ribbon, 1A per common anode)
   J4 – Arrow & voice sync (open-collector, 24 V, 50 mA max)
   J5 – Fire-service override (active low, 4.7 kΩ pull-up)
   J6 – External gong relay (24 V, 0.5 A fuse on-board)
4. Addressing & software handshake
   Otis controllers auto-scan COP/LOP boards at power-up. Set binary address 0001 for main COP, 0010 for rear COP, 0011–1100 for LOPs. If two boards share the same address, the controller alternates between them, causing flicker every 3 s. After addressing, cycle 24 VDC; the green “COMM” LED should blink once every 2 s—steady on means address collision, off means no RS-485 bias voltage (120 Ω termination missing). Nanjing Zhuye ships each board with a 120 Ω resistor already soldered across J2; verify jumper JP1 is closed only on the last board in the chain.
5. Brightness & colour temperature calibration
   Out-of-box current is 20 mA per segment, optimised for 9 mm red acrylic. For blue or white filters, change R11 (SMD 1206) from 30 Ω to 47 Ω to avoid wash-out. Use a lux-meter 1 m straight-on: target 45 cd/m² for office, 70 cd/m² for outdoor lobby. Adjust potentiometer VR1 clockwise increases brightness 15 %; beyond that the onboard LM2596 overheats and triggers thermal shutdown.
6. Cycle-based life model
   The display itself has no moving parts, but LED phosphor degrades and electrolytic capacitors dry out. Nanjing Zhuye accelerated-life data at 85 °C/85 % RH shows 50 000 h until luminance falls to 70 % (L70). Convert hours to elevator cycles:
   Light traffic (residence, 60 trips/day, 30 s door open per trip) – 60 × 365 × 0.5 h = 10 950 h/year → replace ≈ 4.5 years.
   Medium traffic (hotel, 250 trips/day) – 45 000 h/year → replace ≈ 13 months.
   Heavy traffic (metro, 1 200 trips/day) – 219 000 h/year → replace every 6 months, or when luminance < 50 cd/m².
7. Preventive inspection schedule
   Monthly: glance check for missing segments or ghost arrows.
   Quarterly: measure 24 VDC ripple at J1; >1 Vpp indicates supply fatigue, not board fault.
   Annually: photograph the display from the same spot; compare RGB values in Photoshop—>15 % drop in red channel predicts imminent L70 failure.
   Bi-annually: open can and inspect C1 (100 µF, 35 V) for bulging; ESR > 2 Ω means order the Nanjing Zhuye capacitor kit (NY-DCA-CAP-3PCS) and change on site.
8. Replacement procedure (average 8 min)
   a) Power down, tag out.
   b) Photograph ribbon orientation before removal.
   c) Unsnap PCB, transfer plastic stand-offs if not cracked.
   d) Fit new Nanjing Zhuye board, torque screws 0.4 N·m.
   e) Restore connectors in order J3→J1→J2 to avoid spark on 24 V rail.
   f) Power up, verify address LED blink pattern.
   g) Run car to top floor and back, checking direction arrows invert correctly.
   h) Log serial number and cycle counter in maintenance book; keep packaging for R2 recycling.
9. Common field faults & quick cures
   Symptom: random segments flash when motor runs.
   Cause: missing 0 V bond between controller PE and COP can.
   Fix: run 2.5 mm² green/yellow wire, crimp ring terminal under nearest earth bolt.

10. Firmware compatibility matrix
    Boards shipped after Jan-2024 carry firmware v4.12, backward-compatible to OCSS 7.8. If your controller runs 7.5 or earlier, flash update file “DCA26800_v412.hex” via RS-485 using the free Nanjing Zhuye FlashTool (Windows 10/11). Flash time 45 s; do not interrupt power or the bootloader must be recovered with a JTAG clip.
11. Sustainability & take-back
    Nanjing Zhuye offers prepaid UPS labels inside every carton. Returned boards are stripped: gold fingers go to certified refinery, aluminium heat-spreader remelted, LEDs recovered for indium. One recycled board saves 26 kWh compared with virgin mining—enough to power the same elevator for a week.