27002

Check PLC Interface Status

Navigate to Diagnostics > PLC > Interface Signals and examine DB31.DBX status bits for active interlocks.

Look specifically at DB31.DBX1.0 (Emergency Stop) and DB31.DBX1.1 (Feed Enable) status

Verify Safety Door Status

Check machine data MD11210 $MN_SAFE_DOOR_MASK and corresponding PLC inputs for door/guard positions.

Never bypass safety interlocks - resolve the underlying safety condition

Review PLC Program Logic

Use STEP 7 or TIA Portal to examine PLC program blocks FB1-FB3 for interlock conditions and reset requirements.

Check for latched fault conditions that require manual reset even after the physical condition is cleared

Check Channel Status

Navigate to Diagnostics > NC > Channel State and verify current channel mode and status flags.

Look for RESET_REQUIRED or CHANNEL_NOT_READY status indicators

Perform Channel Reset

Execute NC RESET via HMI or press RESET key, then check if MD20110 $MC_RESET_MODE_MASK allows proper reset.

Ensure machine is in safe position before performing reset

Verify Mode Selection

Confirm operating mode selector is in correct position and MD11320 $MN_OPMODE_MASK matches selected mode.

Mode conflicts between HMI selection and hardware selector can cause persistent read-in disable

Review Active Alarm List

Navigate to Diagnostics > Alarms > Active and identify any Class A or Class B alarms that require acknowledgment.

Sort by priority - Class A alarms always block execution until cleared

Check Drive Status

Examine Diagnostics > Drives > Status for fault conditions and verify MD36010 $MA_DRIVE_ENABLE status for each axis.

Drive faults may require power cycle or parameter reset to clear

Clear Prerequisite Alarms

Address root cause of blocking alarms first, then acknowledge using ALARM CANCEL or NC RESET as appropriate.

Some alarms require specific clearing sequence - check alarm help text for proper procedure

Check Spindle Enable Status

Verify DB31.DBX spindle enable signals and examine MD35010 $MA_SPIND_ENABLE_POS_LIMS for spindle readiness.

Spindle orientation or speed reaching commands may be pending acknowledgment

Verify M-Code Acknowledgment

Check PLC interface DB32.DBX for M-code acknowledgment signals and ensure auxiliary functions completed properly.

Tool changer or coolant system faults can prevent M-code acknowledgment

Review Function Block Status

Navigate to Diagnostics > PLC > Function Blocks and check FB2 (Spindle) and FB4 (Auxiliary) for completion status.

Use PLC variable table to monitor real-time status of auxiliary function handshake signals

Check System Memory Status

Navigate to Diagnostics > System > Memory and verify available NC memory and buffer status.

Look for memory fragmentation or buffer overflow conditions in system diagnostics

Clear Program Buffers

Execute program memory reset via Service > NC > Clear Buffers or use MD18080 $MN_MM_NUM_PREP_BLOCKS to adjust preprocessing.

Clearing buffers will lose current program position and require restart

Restart NC Kernel

Perform controlled NC restart via Service > System > Restart NC or power cycle if necessary.

Check system event log after restart for any persistent memory allocation errors