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ErrorLib — Industrial Fault Code Library

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CPF21

Hardware Fault at Communication Start Up

Yaskawa · P1000

What does CPF21 mean?

A hardware fault related to communication circuits was detected during the drive's communication startup sequence. This can prevent the drive from establishing network communication.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Inspect the communication interface module (if applicable) within the Yaskawa P1000 AC Drive, ensuring it is correctly seated and free from visible damage or foreign objects.

  2. 2

    Verify all communication wiring connected to the drive's communication port (e.g., Ethernet, RS-485) for correct polarity, termination (if required), and integrity, checking for loose connections or physical damage.

  3. 3

    Check the drive's configured communication parameters (e.g., protocol, baud rate, network address) against the system specifications to ensure proper initialization of the communication hardware.

  4. 4

    Confirm that the drive's grounding and the communication cable shield (if used) are properly connected to prevent electrical noise or ground loops that could interfere with communication hardware startup.

Browse all codes in this manual (60)
Verified technical data. Last updated: April 2026

Related Faults

AL14Serial Communications AlarmCEMEMOBUS/Modbus Communication ErrorCPF02A/D Conversion Error
Source: Yaskawa P1000
Open Manual (Page 383)Search more codes in this manual