Heidenhain TNC 620 Error Code 302

Heidenhain CNC Major Temperature

Model: TNC 620 | Code: 302

Applicable Systems
TNC 620

Symptoms

Drive temperature fault. The servo drive has reported an overtemperature condition.

Possible Causes

  • Drive cooling fan failure
  • Ambient temperature too high
  • Drive operating at sustained high current
  • Drive heat sink contaminated

Troubleshooting Steps

  1. Step 1: Check the equipment status and fault indicators to confirm the active fault code
    Fault indicator or HMI displays code 302 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 ambient temperature around the equipment with a thermometer
    Temperature is within the specified operating range (typically 10-40 degrees C)
  4. Step 4: Inspect cooling fan operation, airflow paths, and heat sink for dust or blockage
    Fan operating normally, airflow unobstructed, heat sink clean
  5. Step 5: Verify equipment load and duty cycle are within rated capacity
    Load and duty cycle within manufacturer specifications
  6. Step 6: Allow equipment to cool below the alarm threshold before attempting reset
    Temperature readings return to normal operating range
  7. Step 7: Reset the fault after the temperature has normalized: press RESET on the HMI
    Fault clears and equipment resumes operation

How to Reset

To reset: 1) Resolve the temperature issue (fix cooling, reduce load). 2) Wait for temperature to drop below alarm threshold. 3) Press RESET on the HMI. Caution: Repeated overtemperature degrades component lifetime.

Frequently Asked Questions

  • Q: What does fault code 302 mean on the Heidenhain TNC 620?

    Fault 302 indicates a temperature-related fault. The equipment has detected a temperature exceeding the safe operating limit. Check the cooling system, ambient temperature, and equipment loading.

  • Q: Can I continue operating the equipment with fault 302 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