23A-0031

Check FSuC Status Display

Navigate to MOD function → Safety → FSuC Status to view current load and active safety functions. Check for excessive CPU utilization or memory usage indicators.

FSuC load should typically stay below 80% during normal operation

Review Active Safety Functions

Access Setup → Safety → Function Overview to identify all active safety monitoring functions. Disable non-critical safety functions temporarily to reduce system load.

Only disable safety functions after proper risk assessment and machine lockout

Optimize Safety Program Cycle Time

Check MP7760 (Safety cycle time) and increase if set too aggressively. Typical values range from 4-12ms depending on application complexity.

Longer cycle times reduce FSuC load but may affect safety response time

Restart FSuC Service

Navigate to Setup → Safety → FSuC Control and perform a controlled restart of the safety controller to clear any memory leaks or stuck processes.

Verify Physical Connections

Check all Ethernet cables between TNC and FSuC modules. Inspect connectors for corrosion, bent pins, or loose connections. Verify LED status on network ports.

Use Cat6 or better cables for FSuC connections to ensure signal integrity

Test Network Connectivity

Access PLC → Diagnostics → Network Status to verify FSuC device appears in network topology. Check IP address assignment and ping response times.

Network response times over 10ms may indicate communication issues

Check Network Parameters

Verify MP7700 (FSuC IP address) and MP7701 (FSuC subnet mask) match the actual FSuC network configuration. Ensure no IP conflicts exist.

Document all IP addresses in your network topology for future reference

Reset Network Interface

Navigate to Setup → Network → Interface Reset and restart the TNC network interface to clear any communication buffers or stuck connections.

Check FSuC Hardware Status

Access MOD function → Diagnostics → Hardware Status and examine FSuC module indicators. Look for red status LEDs or error flags in the hardware diagnostic display.

Document the exact ID and serial numbers shown in the alarm for warranty tracking

Perform FSuC Self-Test

Navigate to Setup → Safety → Diagnostics → Self Test to run comprehensive FSuC hardware diagnostics. Review all test results for failures.

Self-test will temporarily disable safety functions - ensure machine is in safe state

Check Power Supply Voltages

Verify 24VDC supply to FSuC module using Setup → Diagnostics → Power Monitor. Ensure voltage remains stable between 22-26VDC under load.

Voltage drops during high load conditions often indicate power supply issues

Review FSuC Event Log

Access PLC → Diagnostics → FSuC Event Log to check for hardware fault entries, temperature warnings, or memory errors preceding the communication timeout.

Verify Software Versions

Check Setup → System Info → Software Versions to ensure TNC and FSuC software compatibility. Verify FSuC firmware matches TNC requirements per Heidenhain compatibility matrix.

Keep a record of working software version combinations for rollback purposes

Validate Safety Configuration

Access Setup → Safety → Configuration Check to run automatic validation of safety parameter consistency. Address any configuration conflicts or warnings.

Safety configuration changes require proper authorization and validation

Check Communication Timeout Settings

Review MP7762 (FSuC communication timeout) and MP7763 (FSuC retry count) parameters. Increase timeout values if network latency is high.

Start with 500ms timeout and adjust based on actual network performance

Restore Known Good Configuration

If available, restore a previously working FSuC configuration backup through Setup → Safety → Configuration → Restore Backup.