Heidenhain TNC 620 Error Code 301

Heidenhain CNC Major Communication

Model: TNC 620 | Code: 301

Applicable Systems
TNC 620

Symptoms

Drive communication fault. Communication between the NC and the servo drive has been interrupted.

Possible Causes

  • Drive bus cable disconnected or damaged
  • Drive communication module fault
  • Drive bus termination missing
  • NC communication port fault

Troubleshooting Steps

  1. Step 1: Check the equipment status and fault indicators to confirm the active fault code
    Fault indicator or HMI displays code 301 as active
  2. Step 2: Verify all electrical connections, wiring harnesses, and connector seating
    All connections secure, no corrosion, loose pins, or damaged wires
  3. Step 3: Check the communication cable continuity and connector seating at both ends
    Cable continuity confirmed, connectors fully seated with locking tabs engaged
  4. Step 4: Verify communication parameters (baud rate, node address, protocol) match network configuration
    All communication parameters match the network setup
  5. Step 5: Inspect cable for EMI interference: check routing away from high-voltage lines and motor cables
    Cable routed away from EMI sources, shielding intact
  6. Step 6: Check terminating resistors at bus endpoints if applicable (e.g., PROFIBUS, CANopen)
    Terminating resistors installed at both bus ends
  7. Step 7: Reset the fault after restoring communication: power-cycle the affected node
    Communication restores and fault clears

How to Reset

To reset: 1) Fix the communication cable or parameter issue. 2) Power-cycle the affected node. 3) Verify communication restores. Caution: Check all nodes on the bus.

Frequently Asked Questions

  • Q: What does fault code 301 mean on the Heidenhain TNC 620?

    Fault 301 indicates a communication fault. The equipment has lost communication with a connected device or network. Check the communication cables, connectors, and network parameters.

  • Q: Can I continue operating the equipment with fault 301 active?

    No. The equipment has detected a fault condition and has taken protective action (typically stopping or derating). Continuing to operate without fixing the root cause may cause further damage. Always investigate and fix the fault before resuming operation.

Related Heidenhain Fault Codes

Source: Heidenhain TNC 620 Operating Manual, Heidenhain Documentation

Category: CNC