KUKA Robot codes
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KUKA Robot Controller

Servo/Axis · Basic

Alarm KRC0279

KUKA Robot KRC0279 - ACKNOWLEDGE ERROR 6SC620 <axis number>

A malfunction or communication error has occurred in the Simodrive 6SC620 drive module or processor module that controls the specified robot axis. The acknowledgement handshake between KRC controller and drive electronics has failed, preventing axis operation.

KUKA RobotServo/AxisBasic

KRC0279

KUKA Robot KRC0279 - ACKNOWLEDGE ERROR 6SC620 <axis number>

ACKNOWLEDGE ERROR 6SC620 <axis number>

A malfunction or communication error has occurred in the Simodrive 6SC620 drive module or processor module that controls the specified robot axis. The acknowledgement handshake between KRC controller and drive electronics has failed, preventing axis operation.

Common Causes

  • Loose or corroded connector pins on 6SC620 drive module power or signal cables
  • Firmware version mismatch between KRC4 controller and Simodrive 6SC620 electronics
  • Defective 6SC620 power stage or processor unable to complete boot sequence
  • EMI interference or electrical noise on drive module communication bus from nearby equipment
  • Failed capacitor or power supply component on 6SC620 board causing initialization fault

Troubleshooting Steps

  1. 1Power cycle the entire KRC4 system by switching main contactor OFF for 10 seconds then ON
  2. 2Visually inspect all connector pins on 6SC620 module for corrosion, bending, or loose seating
  3. 3Check Simodrive 6SC620 firmware version in controller diagnostics and update if required via WorkVisual
  4. 4Measure DC voltage at 6SC620 power supply inputs to verify stable 24V and 48V rails
  5. 5Verify drive module diagnostic LEDs show normal status patterns per KUKA service manual
  6. 6Replace Simodrive 6SC620 module if communication error persists after firmware update and connector cleaning

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