KUKA Robot codes
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KUKA Robot Controller

System · Basic

Alarm KRC0412

KUKA Robot KRC0412 - UNKNOWN EXTERNAL MESSAGE (<external message number>)

An external message from the interface CPU or PSX could not be converted into a valid RCX message format. This indicates a communication protocol mismatch or corrupted data transmission between the external controller and the KRC4 control system that prevents proper message interpretation.

KUKA RobotSystemBasic

KRC0412

KUKA Robot KRC0412 - UNKNOWN EXTERNAL MESSAGE (<external message number>)

UNKNOWN EXTERNAL MESSAGE (<external message number>)

An external message from the interface CPU or PSX could not be converted into a valid RCX message format. This indicates a communication protocol mismatch or corrupted data transmission between the external controller and the KRC4 control system that prevents proper message interpretation.

Common Causes

  • Incorrect message format sent from PSX or interface CPU not matching RCX protocol specification
  • Communication cable disconnection or electromagnetic interference between external controller and KRC4
  • Firmware version mismatch between KRC4 and external messaging interface causing incompatible message structure
  • Corrupted or incomplete data packet transmission due to serial communication errors or timeout conditions
  • Invalid message number parameter outside the defined range of supported external messages in the system configuration

Troubleshooting Steps

  1. 1Verify the external message number is within the valid range defined in your system configuration documentation
  2. 2Check all communication cables between PSX or interface CPU and the KRC4 controller for loose connections or damage
  3. 3Review the message format being sent from the external controller against the RCX protocol specification in WorkVisual
  4. 4Compare firmware versions between KRC4 and external interface components to ensure compatibility
  5. 5Enable communication logging on both KRC4 and external controller to capture and analyze the malformed message data
  6. 6Contact KUKA service to verify message protocol definitions and consider upgrading firmware if necessary

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