A02B-0281-B502 is a CNC control module used in controllers manufactured by FANUC.
📌 Description
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Part Number: A02B-0281-B502
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Type: Main CPU / CNC control board
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Series: FANUC 0i-series CNC controller
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Category: CNC main control module
⚙️ Function
This module acts as the central processing unit of the CNC system. It performs:
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NC program (G-code) processing
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Axis interpolation and motion control
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Communication with servo amplifiers and spindle drives
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PMC (Programmable Machine Control) ladder execution
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Management of machine I/O signals
🧩 Where It Is Installed
The A02B-0281-B502 board is mounted inside the CNC main unit rack together with other modules such as:
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Power supply module
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Servo interface modules
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Memory / system software modules (for example A87L-0001-0173 series)
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I/O interface boards
🔧 Typical Use
This module may be replaced when:
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The CNC CPU board fails
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During control unit repair
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When upgrading or replacing the main CNC control unit
🧠 Simple Summary
👉 A02B-0281-B502 = FANUC 0i-series CNC main CPU control board module.
✔ The difference between B500 and B502 versions is usually related to hardware revision or option configuration within the same FANUC control series.


