he FANUC system screen is divided into two types, one is the black screen screen, and the other is the operation screen we enter normally. When the system detects that it cannot maintain the normal operation of the system, it will transfer to the system alarm screen, collectively referred to as the black screen screen.

When entering the system alarm state, the system will:

• Disconnect servo and spindle amplifier excitation

• Cut off communication with I/O LINK

When a system alarm occurs, switch to the screen shown below, which is called the system alarm screen. On this screen, the system tells us the cause of the failure and the direction to solve the problem.

System alarms can be divided into the following three types.

• Alarms detected by software

• Alarms detected by hardware

• Other alarms

Alarms detected by software

The CNC system software is mainly used to detect software anomalies. Typical exception reasons are:
• Detect processing/data inconsistencies based on internal status monitoring software

• Access outside data/command scope

• divide by zero

• Stack overflow

• Stack underflow

• DRAM sum check error

Alarms detected by hardware

Hardware anomalies are mainly detected by hardware. Typical exception reasons are:

• Parity errors (DRAM, SRAM, cache)

• Bus error

• Power alarm

• FSSB cable broken

Other alarms
Other reasons are:

• Alarms detected by peripheral software

• Servo software (watchdog, etc.)

• PMC software (I/O LINK communication abnormality, etc.)

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