28005

Inspect Safety Guards

Visually check all safety doors, guards, and interlocks to ensure they are fully closed and latched. Look for any debris or damage that might prevent proper closure.

Use a flashlight to check for small misalignments or wear on the latch mechanisms that might not be visible at a glance.

Ensure no personnel are inside the guarded area before closing doors to avoid entrapment.

Check HMI Safety Input Status

Access the safety diagnostics screen on the HMI or controller to identify which safety input channel is indicating an open guard. Note the specific input number or name for reference.

Take a screenshot or photo of the diagnostics screen to document the fault for future reference or escalation.

Do not attempt to bypass the safety input signal; this can lead to hazardous conditions.

Perform Safety Reset

After ensuring all guards are closed, perform a safety acknowledgment reset using the designated reset button or key switch as per the machine manual. Monitor if the SLS alarm clears.

If the reset doesn’t clear the alarm, note any additional error messages or status bits that appear during the reset attempt.

Clear the work area before resetting to prevent injury from unexpected motion.

Access Drive Parameters

Connect to the drive using STARTER or Startdrive software via a laptop or HMI interface. Navigate to the Safety Integrated parameters section.

Ensure you have the correct access level or password to view and modify safety parameters, as these are often restricted.

Do not modify safety parameters without proper authorization and documentation; incorrect settings can compromise safety.

Compare Speed Values

Check the actual speed feedback (r0063) against the configured SLS limit (p9531 for motor module). If the limit is below the typical operating speed, this is likely the cause.

Record the current parameter values before making any changes for traceability and rollback if needed.

Ensure the machine is in a safe state before accessing live data to avoid unexpected motion.

Adjust SLS Limit if Necessary

If the SLS limit is too low, consult with a safety engineer to adjust p9531 to an appropriate value based on the machine’s safety requirements and operating conditions. Perform a safety acceptance test after changes.

Document the new parameter value and update the machine’s safety documentation to reflect the change.

Incorrect adjustment of safety limits can lead to hazardous conditions; always validate with a safety test.

Power Down and Lockout

Disconnect power to the machine and follow Lockout/Tagout procedures to ensure safety before inspecting wiring. Verify zero voltage at the control cabinet.

Label all wires before disconnecting anything to avoid mix-ups during reassembly.

Failure to follow Lockout/Tagout can result in severe injury or death from electrical shock.

Inspect Wiring and Terminals

Check the wiring to the safety door switches or enabling devices at the F-DI module terminals. Look for loose connections, frayed wires, or signs of damage near moving parts or cable entries.

Use a magnifying glass to inspect small terminals for corrosion or micro-cracks that might cause intermittent faults.

Do not apply excessive force to terminals; overtightening can damage connections.

Test Voltage and Continuity

After restoring power (with proper safety precautions), use a multimeter to measure 24V on both channels of the safety input at the F-DI module. Test continuity on suspected wires when powered down to identify breaks.

If an intermittent fault is suspected, gently wiggle the wires during testing to see if the signal drops out.

Ensure all personnel are clear before restoring power for testing to avoid injury.

Check Encoder Mounting

Visually inspect the encoder mounting on the motor shaft for any looseness, misalignment, or debris that could cause slipping or incorrect readings.

Mark the encoder position with a marker before tightening to ensure it doesn’t shift during maintenance.

Ensure the machine is powered down and locked out before touching the encoder to avoid injury.

Inspect Encoder Cable

Examine the encoder cable for cuts, kinks, or poor shielding, especially near moving parts. Check connector pins for corrosion or looseness at both ends.

Look for areas where the cable might rub against machine parts during operation; add protective sleeving if needed.

Do not disconnect cables while powered; follow Lockout/Tagout procedures.

Monitor Feedback with Trace

Use the SINUMERIK or drive trace function in STARTER to capture speed feedback (r0063) and SLS status bits at a high sample rate. Look for momentary spikes or dropouts in the speed signal that trigger SLS.

Set the trace to trigger on the SLS activation bit to capture the exact moment of fault for better analysis.

Ensure the machine is in a controlled state during tracing to prevent unexpected motion.

Check Mode Selector Position

Verify the position of the mode selector switch or key switch on the control panel. Confirm if it is set to manual, teach, or setup mode, which often activates SLS by design.

Refer to the machine manual for the exact mode definitions and their associated safety functions.

Do not change modes without understanding the impact on machine operation and safety.

Review PLC Safety Logic

Access the safety PLC program or logic documentation to confirm if SLS activation is programmed for the current mode. Check if the logic matches the intended operation.

If you don’t have direct access to the PLC program, consult the machine’s safety documentation or commissioning report.

Do not modify PLC logic without proper safety validation and authorization.

Educate Operator if Necessary

If the mode is correct and SLS is active as designed, ensure the operator understands the speed limitation in this mode and adjusts operation accordingly. If incorrect, switch to the appropriate mode and test.

Post a quick reference guide near the control panel showing mode functions and speed limits for operator awareness.

Ensure all personnel are aware of mode changes to prevent unexpected behavior during operation.