3001

Access the PLC safety program via HMI menu: [Diagnostics] > [PLC Status] > [Alarm History] to review the last triggered safety logic rung. Check for recent writes to $MRR_EMERGENCY_STOP or MD 20100 (Emergency Stop Mode) activation.

Do not bypass safety interlocks; verify physical emergency stop buttons and safety gate switches are functioning correctly before resuming operation.

Verify parameter MD 20100 (Emergency Stop Delay Time) and MD 20101 (E-Stop Ramp Time) are set correctly. Confirm that the PLC E-stop request signal has been released by checking the safety circuit status and resetting the safety logic if required.

Review the NC Start Interlock (SD 42500 - Program Start Enable) to ensure the PLC safety logic has released the start enable bit before attempting to restart the NC program.

Power-cycle the control system: switch the main breaker OFF for 10 seconds, then ON. Monitor the startup sequence and check if alarm 3001 recurs immediately after booting.

Ensure all axes are in a safe position before power cycling. Do not interrupt the startup self-test sequence.

Access [Diagnostics] > [System Information] > [NCK/PLC Coupling] and verify communication status. Check for any recent error entries in the system log (accessible via HMI > Service > System Events). Look for watchdog timeout messages or real-time violation warnings.

If the alarm persists, examine MD 10000 (Cycle Time NCK) and MD 10001 (Cycle Time PLC) to confirm both are set to supported values (typically 4-8 ms for NCK, 8-16 ms for PLC). Contact Siemens service if cycle time parameters have been modified incorrectly.

Check the axis servo status via HMI menu [Axis Control] > [Servo Status]. Verify that all axes show 'Ready' or 'Running' state and that no servo fault bits are set. Confirm motor enable signals (MD 32100 - Servo Enable) are active for all configured axes.

Review axis limit parameters MD 36100 (Software Limit +) and MD 36110 (Software Limit -) for all active axes. Verify that current axis positions (displayed in [Position] menu) are within these limits. If a limit violation is suspected, manually jog the axis back to a safe position.

Use manual jog commands carefully to avoid collision if the machine state is unknown.

Inspect parameter consistency by accessing [Diagnostics] > [Parameter Check] (if available on your HMI version) or manually cross-verify critical axis parameters: MD 32000 (Axis Type), MD 33000 (Feedback Type), and MD 37000 (Rapid Traverse Rate) against the machine documentation. Re-download the machine parameter set if inconsistencies are found.