Top Okuma OSP CNC Error Codes Explained & How To Fix

Okuma OSP controls (OSP-P200, P300, P300L, U100, U10M, E100 series) are known for tight integration between CNC, drives, and machine mechanics. OSP alarms are direct and usually point to a concrete issue in motion, spindle, ATC, safety logic, or control hardware. 

Alarm 5040 - SERVO ERROR (POSITION DEVIATION)

What it means
The axis position deviation exceeded the allowable limit.

Common causes

• Mechanical resistance on the axis
• Ballscrew or guide contamination
• Excessive feedrate or acceleration
• Servo tuning drift

How to fix

• Jog the axis slowly and check for smooth motion
• Inspect lubrication system and way covers
• Reduce rapid and cutting feed temporarily
• Check servo load and following error values

Alarm 5060 - SERVO OVERLOAD

What it means
Servo motor current exceeded the permissible level for too long.

Common causes

• Heavy cutting load
• Axis crash damage
• Poor lubrication
• Worn thrust bearings

How to fix

• Reduce cutting parameters
• Inspect mechanical components for binding
• Verify lubrication delivery to the axis

Alarm 5220 - SERVO COMMUNICATION ERROR

What it means
Communication between CNC and servo drive failed.

Common causes

• Loose or damaged servo communication cable
• Electrical noise in the cabinet
• Drive power instability

How to fix

• Power off and reseat all servo cables
• Inspect cabinet grounding and shielding
• Check drive power supply voltages

Alarm 3030 - SPINDLE ALARM

What it means
Abnormal condition detected in the spindle system.

Common causes

• Spindle overload
• Tool imbalance or worn tool
• Spindle drive fault
• Cooling fan or chiller failure

How to fix

• Reduce spindle load and test at low RPM
• Inspect tool holder and balance
• Check spindle drive diagnostics and cooling system

 

Alarm 3045 - SPINDLE ORIENTATION ERROR

What it means
The spindle could not reach or hold the commanded orientation.

Common causes

• Orientation encoder problem
• Mechanical slip in belt or coupling
• Incorrect orientation parameters

How to fix

• Inspect spindle encoder and cabling
• Check belts and couplings for slippage
• Re-run spindle orientation adjustment if supported

Alarm 4100 - ATC ERROR

What it means
Automatic tool changer sequence failed.

Common causes

• Tool not seated correctly
• ATC arm position sensor not confirmed
• Low air or hydraulic pressure

How to fix

• Inspect tool pocket and tool holder
• Check ATC sensors and switches
• Verify air and hydraulic pressure levels

Alarm 4110 - TOOL CLAMP / UNCLAMP ERROR

What it means
Tool clamp or unclamp operation did not complete correctly.

Common causes

• Insufficient air or hydraulic pressure
• Worn drawbar components
• Clamp sensor failure

How to fix

• Verify pressure values
• Inspect drawbar and gripper condition
• Check clamp confirmation sensors

Alarm 2600 - OVERTRAVEL

What it means
Axis exceeded software or hardware travel limit.

Common causes

• Incorrect work offset
• Program error
• Axis not properly referenced

How to fix

• Jog the axis away from the limit in manual mode
• Verify work offsets and program zero
• Re-home the machine if required

Alarm 1700 - SAFETY INTERLOCK ACTIVE

What it means
A safety condition prevents machine operation.

Common causes

• Door open
• Chuck or tailstock not clamped
• Safety circuit interruption

How to fix

• Close all doors and guards
• Confirm chuck and tailstock clamp status
• Trace the safety circuit using diagnostics

Alarm 2000 - PMC / SEQUENCE ERROR

What it means
Machine sequence logic condition not satisfied.

Common causes

• Sensor or limit switch not actuated
• Hydraulic or pneumatic condition missing
• Interrupted machine sequence

How to fix

• Use sequence diagnostics to identify the missing condition
• Check sensors, switches, and actuators
• Reset and restart the sequence correctly

Alarm 0945 - MEMORY BOARD / BATTERY LIFE

What it means
The UPS or battery for the control memory is nearing end of life. Parameter loss is likely if the battery fails.

Common causes

• Aging memory UPS battery
• Date and time battery depleted

How to fix

• Replace the memory UPS battery immediately
• Replace the date and time battery on the HMI board at the same time
• Power cycle and verify parameters and clock retention

Alarm 1181 - MCS DIFF OVER

What it means
Mechanical Coordinate System difference exceeded the allowable threshold. The axis position does not match expected feedback.

Common causes

• Encoder and position mismatch
• Servo motor or drive issue
• Mechanical obstruction or collision

How to fix

• Check encoder feedback and cable integrity
• Verify servo drive signals and motor current
• Inspect axis mechanics for binding

Alarm 4085 - FAN MOTOR ERROR (PANEL COMPUTER UNIT)

What it means
A CPU or panel fan is not spinning at the required speed or has stopped.

Common causes

• Fan blocked by debris
• Loose power connector
• Failed fan bearing

How to fix

• Inspect and clean fan blades
• Check fan wiring at the panel computer
• Replace the fan if speed does not recover

Alarm P0700 - NC START-UP ERROR

What it means
General startup fault during OSP initialization.

Common causes

• Power interruption during boot
• Corrupted startup file
• Control hardware instability

How to fix

• Perform a clean power cycle
• Reload a known good backup if repeated
• Inspect control power and cabinet wiring

Alarm P0704 - FILE LOAD ERROR

What it means
A required system or configuration file failed to load at startup.

Common causes

• Corrupted system file
• Damaged storage media
• Improper shutdown

How to fix

• Reload files from verified backup media
• Clean or replace the storage device
• Confirm file integrity after loading

Alarm A101-X / Y / Z - ENCODER OR POSITION ERROR

What it means
Encoder or position mismatch on the specified axis.

Common causes

• Encoder cable damage or intermittent connection
• Servo drive issue
• Mechanical slip or backlash

How to fix

• Inspect encoder cables at the motor and drive
• Swap drive modules between axes for comparison
• Verify encoder coupling to the motor shaft

Alarm B2909 - DIRECTION SEQUENCE NUMBER FAULT

What it means
Motion direction or sequence code is outside the expected range.

Common causes

• Invalid motion sequence
• Corrupted program block

How to fix

• Review program sequence around rapid and motion blocks
• Reset motion state and test with simple moves

Alarm B2910 - UNUSABLE G-CODE

What it means
The control encountered a G-code that is not supported in the current mode.

Common causes

• Program written for another control or machine
• Unsupported CAM post output

How to fix

• Remove or replace unsupported G-codes
• Adjust CAM post for correct OSP syntax

Alarm B2912 - UNUSABLE M-CODE

What it means
An M-code is not valid for the machine configuration.

Common causes

• M-code intended for another model
• Post-processor mismatch

How to fix

• Replace with a supported M-code
• Confirm machine feature availability

Error 3701 - CPU TEMPERATURE TOO HIGH

What it means
Control cabinet CPU temperature exceeded safe limits.

Common causes

• Dust buildup in cooling fans or vents
• Inadequate cabinet airflow
• High ambient temperature

How to fix

• Clean or replace cooling fans and filters
• Improve cabinet airflow
• Check temperature sensors and reboot

Error 3702 - WARM-UP RUN NOT EXECUTED

What it means
Warm-up routine could not complete due to machine or mode conditions.

Common causes

• Warm-up program missing
• Machine not in automatic mode
• Safety door open

How to fix

• Load and execute the warm-up program
• Switch the control to automatic mode
• Close all safety doors

Practical notes for Okuma OSP controls

OSP alarms are usually not abstract software complaints. They are the control telling you that something physical or electrical is out of spec right now - a real mechanical restriction, unstable feedback, missing pressure, or a cabinet condition like heat or power quality.

When you see servo and MCS-related alarms, treat them as feedback integrity or mechanical resistance until proven otherwise. Start with the basics that fail most often: encoder connectors, cable shielding, grounding, and anything that can cause intermittent signals. Then move to mechanics - lubrication delivery, chips in covers, damaged couplings, backlash, or binding that only appears under load.

Startup and file-load alarms are a different class. Assume data integrity or power stability issues first. Improper shutdowns, marginal storage media, and noisy power during boot are common triggers, and repeated faults are a signal to restore from a known-good backup and verify cabinet power and wiring.

Before you replace parts, use what OSP gives you: diagnostics, alarm history, and sequence monitoring. If you can identify the missing condition or the axis that is diverging in the same place every time, you can usually fix the cause instead of swapping hardware in the dark.

 

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