1151

Visual inspection of all E-stop buttons

Check main control panel E-stop, pendant E-stop, and any external E-stops for obvious pressed or stuck positions.

Do not force stuck E-stop buttons - they may have failed for safety reasons

Attempt E-stop reset sequence

Twist each E-stop button clockwise to release, then press RESET on the control panel. Check if alarm clears after each button reset.

Reset E-stops one at a time to isolate which button may be causing the issue

Test E-stop button operation

After clearing alarm, test each E-stop by pressing and releasing to verify proper mechanical operation and electrical continuity.

Machine will stop immediately when testing - ensure safe conditions

Check all door positions

Verify main enclosure doors, electrical cabinet door, and chip conveyor covers are fully closed and latched properly.

Look for door sag or misalignment that prevents proper switch engagement

Inspect door interlock switches

Examine each door switch for proper alignment with door striker plates, check for damaged switch bodies or bent actuators.

Do not bypass or defeat door interlocks - they are required safety devices

Test switch continuity

With doors closed, use multimeter to check 24VDC across switch terminals. Open and close doors to verify switch operation.

Check switch mounting screws - loose switches can cause intermittent faults

Verify wiring connections

Check wire connections at each door switch for tightness, corrosion, or damage. Follow safety circuit wiring per electrical prints.

Power down machine before checking electrical connections

Identify external safety devices

Locate all external safety devices connected to terminals TB3-1 through TB3-4 on the main control board per electrical schematic.

Check machine documentation for customer-added safety devices not shown on standard prints

Check external device power and status

Verify 24VDC power supply to external devices and check device status indicators or displays for fault conditions.

Do not disconnect safety devices while troubleshooting - this may create unsafe conditions

Test safety circuit continuity

Measure 24VDC across safety circuit at TB3 terminals with all external devices in normal operating state.

Temporarily disconnect external devices one at a time to isolate faulty device (ensure safe conditions first)

Check safety relay status indicators

Locate safety relay K7 in electrical cabinet and observe LED status indicators. Refer to relay documentation for LED meaning.

Pilz or equivalent safety relays typically have multiple LEDs showing input, output, and fault status

Verify relay input voltage

Measure 24VDC at safety relay input terminals while safety circuit is complete. Check relay coil voltage per electrical schematic.

Use proper lockout/tagout procedures when working in electrical cabinet

Test relay output contacts

With safety circuit complete and relay energized, check continuity of relay output contacts that feed the NGC control board.

Safety relay outputs typically go to main control board terminals - check electrical prints for exact locations

Replace safety relay if faulty

If relay shows fault indication or fails electrical tests, replace with identical Haas part number maintaining all wire positions.

Safety relay replacement requires qualified technician and functional safety test

Verify safety signal at control board

Measure 24VDC at main control board safety input terminals (typically TB1 or TB2) with safety circuit complete.

Compare voltage readings with electrical schematic to confirm proper signal levels

Check control board status LEDs

Observe safety-related LEDs on main control board while safety circuit is energized. Note any abnormal LED states.

Do not probe control board circuits while powered unless absolutely necessary

Contact Haas technical support

If external safety circuit tests good but control still shows Alarm 1151, contact Haas for control board diagnostics and potential replacement.

Document all test results and alarm history before calling - this helps expedite diagnosis