The error (often accompanied by Alarm 120202) indicates that the Human-Machine Interface (HMI) or panel control system cannot establish vital communication with the Numeric Control Kernel (NCK) inside the Control Unit (CCU). When this communication handshake stalls, your entire CNC system freezes, rendering the machine unusable.
She tapped the softkeys. Nothing.
: Check the lights. If the SF (System Fault) , PS (PLC STOP) , or PF (PLC Fault) LEDs are lit red, the PLC is likely in a stop state or has corrupted data. sinumerik 810d waiting for nck connection
When the machine is powered off and the battery is dead, the volatile SRAM memory loses power. This completely erases the NCK machine data and PLC user programs. Upon subsequent power-up, the control unit has no configuration data to run, preventing initialization and breaking the HMI link. If the error appeared immediately after an extended shutdown or a battery replacement, loss of system data is the definitive cause. 4. Perform an NC and PLC General Reset The error (often accompanied by Alarm 120202) indicates