28002

Check Emergency Stop Status

Navigate to HMI > Diagnostics > Safety > Emergency Stop Status to verify all E-stop buttons are released and safety gates are closed.

Never bypass emergency stop circuits for testing purposes

Verify Safety Input Wiring

Check terminal X122 on Sinamics drive for SS1 input signals (typically DI Safe 0/1). Measure 24VDC presence on safety input terminals using safety-rated multimeter.

SS1 inputs require dual-channel safety signals - both channels must be active

Reset Safety Chain

After clearing physical safety conditions, acknowledge alarm via HMI > Alarms > Acknowledge, then perform safety reset through HMI > Machine > Safety Reset or via safety PLC.

Ensure all personnel are clear of machine before safety reset

Check PROFIsafe Status

Navigate to HMI > Diagnostics > Drive > PROFIsafe to check F_Dest_Add parameter and communication status. Verify green status indicators for all safety-relevant drives.

Parameter P9601 shows PROFIsafe connection status - value 3 indicates active communication

Verify Safety Address Configuration

Check parameter P9610 (F-Dest-Address) matches SINUMERIK safety configuration. Compare with HMI > Commissioning > Drive > Safety > Address Settings.

Incorrect safety addresses can cause intermittent SS1 activation

Monitor Safety Telegram Timing

Check P9611 (F_Mon_Time) and P9612 (F_Par_Version) for proper safety monitoring time configuration. Default monitoring time should be 150ms for SINUMERIK systems.

Use STARTER software to monitor real-time PROFIsafe telegram status

Verify SS1 Parameter Settings

Check parameter P9650 (SS1 monitoring time) and P9651 (SS1 ramp-down time). Navigate to HMI > Commissioning > Drive > Safety Functions > SS1 Configuration.

Typical SS1 ramp-down time is 1-5 seconds depending on application inertia

Validate Safety Signature

Compare P9761 (calculated safety signature) with P9762 (accepted safety signature). Mismatched signatures prevent safety function activation.

Safety signature changes require complete safety validation and acceptance

Check Safety Function Enable

Verify P9601.0 (SS1 enable bit) is set to 1. Access via STARTER > Safety Integrated > Basic Functions > SS1 or HMI > Commissioning > Drive > Safety > Function Enable.

Parameter P9650 = 0 disables SS1 function entirely

Test Safety Input Modules

Check X122 terminal block safety inputs using oscilloscope to verify clean 24VDC signals without noise or voltage drops. Measure both channels of dual-channel safety inputs.

Safety inputs require <2ms switching time and >20VDC for reliable detection

Verify Safety Relay Operation

Test external safety relays feeding SS1 inputs. Check relay coil resistance and contact operation. Replace safety relays if contact bounce or delayed switching detected.

Use only safety-rated relays with appropriate SIL rating for SS1 circuits

Inspect Terminal Connections

Check X122 terminal torque specifications (0.5-0.6 Nm) and verify no loose connections. Look for corrosion or damaged terminals affecting safety signal integrity.

Use terminal marking strips to identify safety circuits clearly

Review Safety PLC Program

Access HMI > Commissioning > Safety Integrated > Program to check safety logic blocks. Look for incorrect F_SS1 function block connections or timer configurations.

Safety program modifications require safety engineer authorization

Check Safety Variable Status

Monitor safety I/O variables in HMI > Diagnostics > Safety > Variable Status. Verify safety input states match physical conditions and no stuck variables exist.

Use force tables cautiously - forcing safety variables can mask real faults

Validate Safety Program Checksum

Verify safety program integrity through HMI > Safety > Program Info > Checksum. Compare with documented safety validation checksum from commissioning records.

Corrupted safety programs must be restored from validated backup only