Description
FANUC A20B‑3900‑0160 — Memory/Storage Module for CNC Controllers
The A20B‑3900‑0160 is a memory module (FROM + SRAM) used in industrial FANUC CNC controller systems. It stores firmware, configuration data, and other essential digital information that the controller needs to operate.
📌 Key Details
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Part Number: A20B‑3900‑0160
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Type: Memory board/module (FROM + SRAM)
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Function:
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Contains Flash ROM (FROM) — typically 16 MB of firmware/program storage
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Contains Static RAM (SRAM) — typically 1 MB for storing runtime data and control variables
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Use: Plugs into the main controller PCB of a FANUC CNC system to hold essential software/parameters that the CNC needs to boot and run.
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Applications: Commonly used in FANUC i‑Series CNC controls including 16i, 18i, 21i, and also later 30i/31i/32i series controllers.
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Status: Often discontinued by FANUC, but available new surplus, refurbished, or repaired via aftermarket suppliers.
🧠 How It Works
This module acts as non‑volatile storage for the CNC controller’s operational software and parameters (FROM), and temporary data (SRAM) used during execution. Without it, the CNC would fail to initialize or would lose critical program and parameter data.
⚙️ Typical Installation Context
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Installed as part of the controller electronics rack, usually alongside the main CPU board, servo/axis modules, and other memory modules.
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If replacing this module, it’s important to restore machine parameters and backups to avoid loss of configuration data.