SR0040

Inspect Ethernet Cable Connection

Check both ends of the Ethernet cable at the CNC control and the network switch/router to ensure they are securely plugged in. Look for any bent pins or loose connectors.

Use a cable tester if available to quickly verify continuity and proper wiring.

Ensure the machine is powered down before handling cables to avoid accidental damage to the control system.

Examine Cable for Physical Damage

Inspect the entire length of the Ethernet cable for cuts, kinks, or wear that could disrupt communication. Replace the cable if any damage is found.

Keep spare Ethernet cables of appropriate length on hand for quick replacement.

Do not use damaged cables as they can cause intermittent issues.

Test with a Different Cable

Swap the current cable with a known good Ethernet cable to rule out cable-specific issues. Monitor the system for alarm recurrence after replacement.

Label cables for easy identification during future troubleshooting.

Ensure the replacement cable meets the required category (e.g., Cat5e or Cat6) for the network speed.

Access CNC Network Settings

Navigate to the network settings menu on the Fanuc CNC control to view the assigned IP address. Note down the current IP, subnet mask, and gateway settings.

Take a photo of the settings for reference in case of accidental changes.

Incorrect changes to network settings can cause further communication issues.

Check for IP Conflicts

Use a network scanning tool or manually check other devices on the network to see if any share the same IP address as the CNC control. Document any conflicts found.

Tools like Advanced IP Scanner can quickly identify all devices and IPs on the network.

Ensure you have permission to scan the network to avoid security concerns.

Reassign IP Address if Necessary

If a conflict is found, assign a unique static IP address to the CNC control that does not overlap with other devices. Restart the control to apply changes and monitor for alarm clearance.

Reserve the IP address in the router settings to prevent future conflicts.

Consult with IT staff if unsure about available IP ranges.

Check Switch/Hub Power and Status

Verify that the network switch or hub is powered on and check for activity lights corresponding to the port connected to the CNC. No lights or blinking errors indicate a potential failure.

Most switches have diagnostic LEDs—refer to the manual for specific error patterns.

Do not unplug power to the switch without notifying other users as it may disrupt network activity.

Test Different Port on Switch

Move the Ethernet cable from the CNC to a different port on the switch to rule out a specific port failure. Observe if the alarm clears after reconnection.

Mark the original port to avoid confusion during future troubleshooting.

Ensure the new port is configured similarly if VLANs or specific settings are in use.

Replace Switch if Faulty

If no ports work or the switch shows signs of failure (e.g., no power, no activity), replace it with a known good switch. Reconnect all devices and test communication.

Keep a spare switch on hand for critical systems to minimize downtime.

Backup switch configurations if applicable before swapping.

Monitor Network Traffic

Use network monitoring tools or router logs to check for high traffic or bandwidth usage during the time of the alarm. Look for spikes that correlate with the error.

Free tools like Wireshark can help analyze traffic if no built-in monitoring is available.

Avoid running unnecessary scans during peak operation times.

Identify High-Traffic Devices

Determine if other devices or processes on the network are consuming excessive bandwidth (e.g., large file transfers). Temporarily reduce their activity if possible.

Work with IT to prioritize CNC traffic using Quality of Service (QoS) settings.

Do not disable critical systems without authorization.

Optimize Network Usage

If congestion is confirmed, schedule non-critical network activities during off-peak hours or segment the network to isolate CNC communication. Test if the alarm persists after adjustments.

Consider a dedicated network segment for CNC machines to avoid interference.

Network changes may require IT department approval.

Check Firewall Settings on CNC

Access the CNC control’s network settings to see if an internal firewall is enabled and blocking Ethernet communication. Note any restricted ports or protocols.

Refer to the Fanuc manual for default communication ports used by the system.

Do not disable firewalls without understanding the security implications.

Review Network Firewall Rules

Work with IT to check if the network firewall is blocking traffic to or from the CNC’s IP address. Look for rules that might restrict specific ports or protocols.

Common ports for Fanuc systems include 8193 for FOCAS communication—ensure they are open.

Incorrect firewall changes can expose systems to security risks.

Test with Firewall Temporarily Disabled

If permitted, temporarily disable the firewall on the CNC or network to test if communication resumes. Re-enable it after testing and create exceptions if needed.

Document any changes made to firewall settings for future reference.

Only disable firewalls in a controlled environment and for a short duration.