Okuma Alarm B-2175 – MCS Servo Link Disconnection
The Okuma Alarm-B 2175 indicates a communication failure between the NC control and the MCS servo system. This alarm appears when the servo link connection is interrupted, preventing the servo unit from receiving proper control commands from the CNC system.
When this alarm occurs, axis movement may stop completely, servo drives may enter a protection state, and the machine can become unable to continue automatic operation. In many cases, the alarm is related to unstable communication between the servo amplifier, MCS controller, and the NC unit.
Common causes of Okuma Alarm-B 2175 include:
- Disconnected or damaged servo communication cables
- Faulty MCS servo amplifier
- Power supply instability
- Loose connectors or oxidized terminals
- Servo control board failure
- NC communication errors
- Electrical noise or grounding problems
- Internal hardware malfunction in the servo system
This alarm may appear:
- during machine startup,
- after emergency stops,
- after electrical interruptions,
- during axis movement,
- or randomly while machining.
In some situations, the machine may temporarily recover after a restart, but recurring alarms usually indicate an underlying hardware or communication issue that requires proper diagnosis.
Recommended troubleshooting steps:
- Inspect all MCS servo communication cables and connectors
- Check servo amplifier status LEDs and diagnostic indicators
- Verify power supply voltages
- Inspect grounding and shielding conditions
- Check for damaged servo boards or overheated components
- Review NC and servo diagnostic screens
- Test communication stability between NC and servo system
Because the MCS servo link is a critical communication path inside the Okuma control architecture, unresolved issues can eventually lead to machine downtime or additional servo-related alarms. Professional diagnosis is often required to isolate whether the problem originates from the servo drive, control electronics, communication wiring, or the CNC system itself.
