What causes Haas alarm 1311?

Power was cycled or E-stop was pressed while machine was not at home position, causing loss of absolute position reference. Encoder battery voltage has dropped below minimum threshold and machine was powered off, losing absolute encoder position data. Parameter changes related to home position, encoder scaling, or axis configuration were made requiring the axis to be re-homed. Servo amplifier was replaced or encoder cable was disconnected while power was on, corrupting position data in MOCON memory. MOCON board battery is failing or discharged, causing loss of stored home position data during power-down.

How do I fix Haas alarm 1311?

1. Step 1: Press POWER UP button and allow all axes to complete their home cycle automatically, verify each axis homes without error 2. Step 2: Check encoder battery voltage in Diagnostics page, should read above 3.0 VDC, replace battery if below 2.8 VDC 3. Step 3: If specific axis will not home, manually jog axis away from home switch then back to verify home switch is functioning 4. Step 4: Verify home switch operation in Diagnostics Switches page while manually pressing each axis home switch 5. Step 5: Check MOCON board battery voltage at battery terminals, should be 3.0-3.6 VDC, replace if low or install new CR2032 battery 6. Step 6: If alarm persists after successful homing, check for loose connections on MOCON board or corrupted parameters requiring factory reset

axismd.ai

Haas Controller

Servo/Axis · Basic · 5-20 minutes

Alarm 1311

Haas Alarm 1311 - Axis Home Required

Alarm 1311 fires when the Haas NGC control loses confidence in absolute axis position reference, requiring a zero return cycle to re-establish machine coordinates. This typically occurs after power loss without battery backup, servo faults, E-stop conditions, or encoder feedback issues that invalidate the control's position data.

HaasServo/AxisBasic5-20 minutes

1311

Haas Alarm 1311 - Axis Home Required

Axis Home Required

Root Cause Summary

Alarm 1311 fires when the Haas NGC control loses confidence in absolute axis position reference, requiring a zero return cycle to re-establish machine coordinates. This typically occurs after power loss without battery backup, servo faults, E-stop conditions, or encoder feedback issues that invalidate the control's position data.

Safety

Ensure all personnel are clear of machine envelope before initiating home cycle - axes will move at rapid traverse speed to travel limits without collision detection.
Do not reach into machine during homing sequence - rapid axis motion to home switches cannot be interrupted without triggering E-stop which will require re-homing.
When manually checking home switches, use HANDLE JOG or single-step axis motion only - never bypass home switches or defeat interlocks to clear this alarm as axis crash and control damage will result.

Causes and Fixes

1
Check Battery Status
Navigate to CURRENT COMMANDS > ALARMS/MESSAGES and check for any battery-related alarms. Also check parameter 393 (BATTERY LOW) status.
Battery voltage should read above 3.0V in the diagnostics screen
2
Perform Zero Return
Press ZERO RETURN button, then press CYCLE START. All axes will move to their home positions and establish machine coordinates.
Ensure work area is clear before initiating zero return cycle
3
Replace Battery if Needed
If battery voltage is low, replace the lithium battery on the control board. Reset parameter 393 after replacement.
Always perform zero return after battery replacement to verify position retention

DIY Feasiblehigh confidence

Call a technician if:

·Encoder replacement needed
·Servo drive replacement required
·Multiple recurring home position loss

Prevention

Replace control battery every 2-3 years
Maintain clean encoder connections
Perform regular home position verification
Keep parameter backups current

Common Mistakes

Attempting to jog before homing
Ignoring underlying servo faults
Not checking battery status during troubleshooting
Forcing homing with faulty switches

Related Alarms

401 402 403 1312 1313

Seeing Multiple Alarms?

Seeing another alarm with this one? Enter the code.

Get machine-aware diagnosis

AxisMD logs alarms against your actual machines, tracks patterns, and gives AI context your manual doesn't have.

Start free

Was this guide helpful?

Always verify with your machine manual or a certified technician before performing service procedures.