Description

Mitsubishi machine room elevator motherboard P1 board KCD-911A KCD-912B  Brief introduction

1. What KCD-911A Really Is

• Core: 32-bit RISC MCU, 60 MHz, 1 ms safety loop refresh
• Memory: 1 Mb FRAM + 4 Mb SDRAM—20-year data retention without battery
• Safety: dual-channel SIL-2 CPU, redundant CAN, 24 V watchdog
• Interfaces: CAN-open 125 kbit/s, RS-485, 0–10 V speed reference, incremental encoder 8,192 ppr
• I/O: 48 digital inputs, 24 relay outputs, 6 analogue channels
• Power: 24 VDC ±10 %, 2.5 A peak, 1.0 A typical
• Size: 200 × 140 × 40 mm—DIN-rail or chassis mount
• Firmware: pre-loaded V2.06; checksum matches Mitsubishi original 0x6B2A

2. Where It Is Used

• Mitsubishi NPX, NEX, GVF-L passenger elevators 1.0–2.5 m s⁻¹
• Machine-room-less (MRL) or machine-room (MR) installations
• Modernisation kits upgrading relay logic to VVVF
• Suitable for 1–64 floors, simplex or group (≤8 cars)

3. Commissioning – 20-Minute Hot Swap

1. Photograph wiring—note DIP-switch S1-5 position.
2. Remove old board—undo 4 DIN-rail clips; unplug 48-way ribbon, 6-way CAN, 4-way encoder.
3. Inspect ribbon—if bent pins >3, replace cable (Nanjing Zhuye part CB-48-400).
4. Insert KCD-911A—snap until latches click; reconnect all keyed plugs.
5. Set DIP-SW1:
   • S1-5 ON = 2 m/s, OFF = 1 m/s
   • S1-8 ON = TWIN lower car
6. Power on—green D1 blinks 2 Hz for 8 s while FRAM checksum is verified, then steady.
7. Run one full learn trip—verify encoder counts every floor.

4. Daily Operation – What the Board Actually Does

• Updates speed curve every 1 ms; jerk <0.5 m/s³—passengers feel nothing
• Auto-compensates for rope stretch; stores creep data every trip
• Built-in 24 h self-test—if encoder drift >0.5 mm, “Learn Fault” is logged
• Regenerative braking feeds 15 % of motor energy back to 24 V bus—saves battery life
• Temperature sensor derates current above 70 °C—no summer shutdowns

5. Replacement Cycle & Preventive Maintenance

• High-traffic office (>1,000 starts day⁻¹) – blow dust every 3 months, replace board every 6 years
• Residential tower (300–600 starts day⁻¹) – inspect annually, replace every 10 years
• Low-rise freight (≤200 starts day⁻¹) – inspect every 18 months, replace every 12 years

• D1 LED stays red for >5 s (internal 3.3 V rail fault)
• CAN “CPU Fault” logged ≥3 times in 30 days
• Encoder count skips >8 pulses per revolution
• FRAM checksum error 0xF0 after power dip (data corrupt)
• Safety chain opens sporadically with no external cause

6. Extending Life – 3 Pro Tips

1. Keep 24 VDC ±5 %; spikes above 30 V destroy the on-board buck converter
2. Close controller door; dust on edge connectors is the #1 killer
3. Route encoder cable away from brake resistor; radiated heat above 70 °C halves MCU life

7. Why Buy KCD-911A from Nanjing Zhuye Elevator Parts?

• Factory-new, not refurbished; passes ICT, 4-hour burn-in at 60 °C, and final functional test
• Firmware V2.06 pre-flashed; matches Mitsubishi original checksum, no teach-in required
• Anti-static aluminum bag + foam box — safe for air freight
• Dual stock: 420 pcs Nanjing, 150 pcs Dubai — next-day delivery to 65 countries
• Bundle kit: motherboard + 48-way ribbon + DIP-switch tool — 8 % discount
• 24 months warranty against drift or communication failure
• 7×24 WhatsApp/WeChat video support; average response 10 minutes

Conclusion