ALARM light constantly on, CPU hardware failure; I/O bus error check expansion cable connection; Replace the CPU
BATT LOW light on, battery voltage low, replace battery within one week
All I/O in the expansion rack is not working, and the I/O control unit or I/O interface unit is not installed; Loosening inspection of connecting cables II101 and II002; Re plug and unplug the connecting cable and lock it securely
Duplex system cannot start. Two CPU memory packets are inconsistent; Duplex unit switch setting error check for memory capacity and write protection switch; Confirm that the system switch is DPL and both CPUs are ON/OFF
The configuration of the "I/O VERITY ERROR" I/O unit during programming does not match the actual situation; Check if the current consumption exceeds the limit when the power capacity is insufficient; Check the I/O unit model and slot position
