2D4-0000

Check PLC Connection Status

Navigate to MOD function → System Info → PLC Status to verify PLC communication state and connection parameters.

Look for 'PLC Ready' status indicator - anything else indicates communication issues

Verify Network Configuration

Access Setup → General → Network Settings and confirm PLC IP address, subnet mask, and gateway settings match your PLC configuration.

Document current settings before making changes

Test PLC Ping Response

Use Setup → Service → Network Diagnostics to ping the PLC IP address and verify physical network connectivity.

Response times over 10ms may indicate network congestion affecting script startup

Restart Communication Services

Execute MOD function → Reset → Communication Reset to reinitialize PLC communication interface without full system restart.

Verify Python Script Path

Check MP7681 PYTHON_SCRIPT_PATH parameter in Setup → Machine Parameters → Path Settings to ensure correct script file location.

Use TNC file manager to verify the script file actually exists at the specified path

Validate Script Permissions

Navigate to file location using Setup → File Management and verify Python script has execute permissions and is not corrupted.

Never edit Python scripts directly on the TNC - use proper development environment

Check Python Runtime Parameters

Verify MP7682 PYTHON_TIMEOUT and MP7683 PYTHON_BUFFER_SIZE parameters are within valid ranges (timeout: 1-300 seconds, buffer: 1024-65536 bytes).

Default timeout of 30 seconds is usually sufficient - longer timeouts may indicate script performance issues

Test Script Syntax

Use Setup → Service → Python Diagnostics to perform syntax check on the target script before attempting execution.

Check Python Service Status

Access MOD function → System Info → Services and verify 'Python Runtime Service' shows 'Running' status.

Service should auto-start on boot - manual start indicates configuration issues

Verify Python Installation

Navigate to Setup → Software Options → Python Support and confirm Python runtime is properly licensed and installed.

Python support requires specific TNC software version and license - check with machine builder

Restart Python Service

Use MOD function → Service Control → Python Service → Restart to reinitialize the Python runtime environment.

Monitor system log during restart for any Python initialization error messages

Check System Resources

Verify available memory and CPU usage in System Info - Python requires minimum 64MB free RAM and <80% CPU utilization.

Monitor PLC Variables

Use Setup → PLC → Variable Monitor to observe Python start request signals (typically V.G.PYTHON_START and V.G.PYTHON_READY variables).

Start signal should pulse high for minimum 100ms, ready signal should respond within 5 seconds

Check PLC Cycle Time

Verify PLC scan time in System Info → PLC Status is under 10ms - longer times may cause communication timeouts.

PLC cycle times over 50ms indicate serious performance issues requiring immediate attention

Review PLC Error Log

Access Setup → PLC → Error Log to identify any PLC-side errors related to Python script communication or execution requests.

Validate Handshake Sequence

Use PLC diagnostics to trace the complete handshake sequence from script start request through acknowledgment and ready confirmation.