KUKA Robot codes
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KUKA Robot Controller

Communication · Basic

Alarm KRC0426

KUKA Robot KRC0426 - KEY COMBINATION <KCP> INADMISSIBLE

This alarm indicates that the KRC controller detected simultaneous pressing of multiple keys on the KCP (KUKA Control Panel) teach pendant, which is not a valid input combination. The controller's input validation system rejected this inadmissible key combination to prevent unintended robot movements or erroneous commands that could result from multi-key conflicts.

KUKA RobotCommunicationBasic

KRC0426

KUKA Robot KRC0426 - KEY COMBINATION <KCP> INADMISSIBLE

KEY COMBINATION <KCP> INADMISSIBLE

This alarm indicates that the KRC controller detected simultaneous pressing of multiple keys on the KCP (KUKA Control Panel) teach pendant, which is not a valid input combination. The controller's input validation system rejected this inadmissible key combination to prevent unintended robot movements or erroneous commands that could result from multi-key conflicts.

Common Causes

  • Operator pressing multiple keys simultaneously on the KCP teach pendant
  • Stuck or physically damaged keys on the KCP causing contact bounce or multiple simultaneous registrations
  • Worn or defective membrane keyboard contacts creating false multi-key signals
  • Software glitch in the KCP input processing circuit or driver firmware
  • Contamination or debris under the keypad membrane affecting key isolation

Troubleshooting Steps

  1. 1Release all keys on the KCP teach pendant and press the reset/acknowledge button to clear the alarm
  2. 2Verify the operator is pressing only one key at a time and avoiding accidental multi-key contact during normal operation
  3. 3Perform a functional test of each individual key on the KCP to ensure proper isolation and no stuck keys
  4. 4Clean the KCP keypad with an appropriate contact cleaner and soft brush to remove any contaminants or debris
  5. 5If alarm recurs frequently, perform a firmware update on the KRC controller to ensure the input validation logic is current
  6. 6If problem persists, replace the KCP teach pendant as the keyboard matrix or input circuit may be defective

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