320-0016

Check PLC Interface Status

Navigate to MOD function → System Info → PLC Status to verify PLC communication state and interface card status.

Look for red status indicators or timeout messages in the PLC status display.

Verify Physical Connections

Inspect all cables between TNC and PLC interface, checking for loose connections, damaged cables, or corroded contacts on the PLC communication ports.

Power down both TNC and PLC before checking physical connections.

Test Communication Parameters

Access Setup → Machine Parameters → PLC Interface and verify baud rate, protocol settings, and timeout values match PLC configuration.

Document original settings before making changes for easy rollback.

Reset PLC Interface

Perform PLC interface reset via MOD function → Reset → PLC Interface Reset, then monitor for alarm recurrence during next strobe operation.

Review PLC Marker Assignment

Check Setup → PLC Configuration → Marker Assignment to verify the strobe output markers for the affected channel are properly defined and not conflicting.

Use the PLC marker map display to identify any overlapping assignments.

Verify Marker Access Rights

Ensure the assigned PLC markers have write permissions enabled and are not set as read-only or protected in the PLC program.

Changing marker permissions may affect other machine functions.

Test Marker Functionality

Use MOD function → PLC → Manual Marker Test to manually write test values to the problematic markers and verify successful data transfer.

Reload PLC Configuration

Backup current settings, then reload PLC configuration via Setup → PLC Configuration → Load Configuration to refresh marker assignments.

Check Channel Buffer Status

Navigate to MOD function → Channel Info → Buffer Status for the affected channel to view current buffer utilization and any overflow conditions.

Buffer utilization above 90% often indicates impending overflow issues.

Clear Channel PLC Buffer

Execute buffer clear via MOD function → Channel → Clear PLC Buffer for the specific channel showing the alarm.

Clearing buffers will reset all pending PLC operations for that channel.

Adjust Buffer Size Parameters

Access Setup → Machine Parameters → Channel Parameters and increase PLC buffer size parameters (typically MP7680-MP7689 range) for the affected channel.

Monitor Buffer Performance

Run test program with PLC strobe operations while monitoring buffer status to verify increased capacity resolves the transfer issue.

Verify PLC Program Status

Check MOD function → PLC Status → Program State to confirm PLC program is running and not in error or stopped state.

Look for specific error codes or halt conditions in the PLC status display.

Review PLC Error Log

Access Setup → PLC → Error Log to identify any PLC program errors that occurred around the time of the 320-0016 alarm.

Restart PLC Program

Stop and restart the PLC program via MOD function → PLC Control → Program Restart, then test strobe functionality.

Restarting PLC may affect other machine operations in progress.

Validate Strobe Handling Code

Review PLC program sections that handle TNC strobe inputs to ensure proper marker handling and no blocking conditions exist.