What causes Haas alarm 312?

M30 or M02 command issued while spindle is still running due to missing M05 spindle stop command earlier in the program. Program end command executed with an active G65 macro call that has not returned, leaving the macro stack unbalanced. Pending auxiliary function or M-code that did not receive completion feedback from IOCON or external device before end of program. Program contains M30 in a subroutine rather than the main program, causing incorrect nesting and control flow errors. Control software bug or memory issue preventing proper program termination sequence from executing after certain combinations of codes.

How do I fix Haas alarm 312?

1. Step 1: Review the last several blocks before the M30 or M02 to ensure M05 spindle stop and M09 coolant off are present and executed 2. Step 2: Check the program structure to verify M30 appears only at the end of the main program and not inside subroutines or macro calls 3. Step 3: Run the program in single block mode and watch the Diagnostics screen for any M-code or auxiliary outputs that remain active through program end 4. Step 4: If using macros or subroutines, verify all G65 calls have matching M99 returns and the call/return structure is properly balanced 5. Step 5: Power cycle the control to clear any memory errors and re-run the program to see if the alarm is intermittent or repeatable 6. Step 6: Update the control software to the latest available version from Haas as this alarm can occasionally be caused by specific code combination bugs that are patched in updates

Haas codes

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Haas Controller

Program/G-code · Basic · 10-20 minutes

Alarm 312

Haas 312 - PROGRAM END | Haas CNC Alarm

Alarm 312 occurs when the Haas NGC control encounters an M98 subprogram call but cannot locate the specified O-number program in active memory. The most common cause is the subprogram was never loaded into memory or was accidentally deleted. The typical fix is loading the missing subprogram into memory via the Program menu.

HaasProgram/G-codeBasic10-20 minutes

312

Haas 312 - PROGRAM END | Haas CNC Alarm

PROGRAM END

This alarm indicates the control has reached an M30, M02, or percent sign program terminator but has detected an error condition that prevents normal program end procedures from completing. The control expects certain machine states or completed actions before allowing program end, such as all axes stopped, spindle off, and coolant off. If these conditions are not met or the program structure is malformed, the alarm fires instead of executing the reset and rewind functions.

Root Cause Summary

Safety

Main program will stop

Causes and Fixes

1
Identify the missing subprogram number
Press ALARM to view the alarm details. Note the line number where execution stopped, then press PROGRAM and use the cursor to find the M98 line that caused the alarm. Record the O-number being called (e.g., M98 P1001 calls subprogram O1001).
2
Check if subprogram exists in memory
Press PROGRAM, then LIST PROG soft key. Scroll through the program list to verify if the O-number from step 1 exists in memory. If not found, the subprogram needs to be loaded.
3
Load the missing subprogram
Use DNC, USB, or network transfer to load the missing subprogram. Press PROGRAM, then appropriate transfer method (USB/DNC). Navigate to the subprogram file and transfer it to memory.
Always verify subprogram dependencies before running a main program to avoid mid-cycle stops.
4
Reset alarm and resume
Press RESET to clear alarm 312. Press CYCLE START to resume program execution from the M98 call.

DIY Feasiblehigh confidence

Call a technician if:

·Memory hardware errors preventing program storage
·Persistent alarm after confirming subprogram exists and M98 syntax is correct

Prevention

Always verify all subprograms are loaded before running main programs
Use program templates with consistent O-number schemes
Enable memory protect for critical subprograms
Maintain organized backup system for all programs and subprograms

Common Mistakes

Assuming subprograms transfer automatically with main programs
Not checking O-number syntax when copying M98 calls between programs
Deleting subprograms without checking if other programs call them
Running programs without verifying all dependencies are in memory

Related Alarms

313 314 315

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