280-04B1

Check Emergency Stop Status

Verify all E-STOP buttons are released and twisted out. Check machine status line for emergency stop indicators.

Never bypass safety circuits - resolve the root cause of safety system activation

Verify Safety Door Interlocks

Ensure all safety doors and guards are properly closed and latched. Check PLC status in MOD function for door switch states.

Use PLC status display to identify which specific interlock is preventing operation

Reset Safety System

After clearing all safety conditions, press the machine RESET button, then attempt NC Start again.

Some machines require a specific reset sequence - check machine manual for proper procedure

Check Reference Point Status

Press POS key and verify all axes show valid reference marks (no flashing coordinates). Look for 'REF' indicators in position display.

Flashing position values indicate axes without valid reference

Execute Reference Point Run

Select Manual mode, press REF key, then move each axis to its reference point using direction keys until reference mark is found.

Ensure clear path to reference positions before initiating reference run

Verify Reference Completion

Confirm all axes show solid position values and REF status is active. Switch to Program Run mode and retry NC Start.

Some machines auto-reference on power-up - check MP7500 parameter for reference behavior

Verify Program Selection

Press PGM MGT key and confirm a valid NC program is selected (highlighted). Check program name appears in status line.

Program must be syntactically correct and completely loaded before NC Start is enabled

Check Operating Mode

Ensure control is in Program Run (Full Sequence or Single Block) mode. Verify mode selector switch position matches display.

NC Start is only valid in Program Run modes, not Manual or Electronic Handwheel modes

Test Program Syntax

Use Test Run mode to verify program syntax. Press TEST key, then NC Start to check for programming errors without machine movement.

Test Run will reveal syntax errors that prevent normal program execution

Check Tool Change Status

Verify no tool change is in progress. Check TOOL CALL status in position display and ensure tool change arm is in home position.

Incomplete tool changes often require manual completion before NC Start is allowed

Verify Spindle Readiness

Check spindle status indicators. If spindle orientation is active, wait for completion or press spindle stop to cancel.

Never force spindle movement during orientation - allow automatic completion

Reset Tool Management

If tool errors persist, access TOOL table and verify current tool data. Use TOOL CALL T0 to clear active tool if necessary.

Tool length compensation errors often require manual tool measurement or table correction

Check PLC Status Display

Press MOD key, select PLC function, and review marker status. Look for blocking conditions in M markers or custom logic.

Machine builder documentation often lists specific PLC markers that control NC Start enable

Verify Machine Prerequisites

Check hydraulic pressure, coolant levels, air pressure, and other machine systems. Ensure all prerequisite conditions are met.

Do not override PLC safety logic - resolve underlying machine condition issues

Review Machine Manual

Consult machine builder documentation for specific NC Start prerequisites. Contact machine manufacturer if PLC blocking persists.

PLC program comments often explain blocking conditions - review ladder logic if accessible