AH500 Hardware and Operation Manual 
12-4 
12.1.4  Viewing Error Logs 
When an error occurs, a corresponding error code generated by a system is recorded in a CPU module. 
Twenty error logs at most can be stored in the CPU module. If there are more than twenty error logs generated, 
the oldest error log will be overwritten by the latest error log. However, if a memory card is installed in the CPU 
module, the twenty error logs are automatically backed up in the memory card before the oldest error log is 
overwritten. One thousand error logs at most can be stored in the memory card. If there are more than 1000 
error logs which will be stored in the memory card, the twenty oldest error logs will be overwritten by the twenty 
latest error logs. 
(1)  After ISPSoft is started, click System Log on the PLC menu. 
 
 
(2)  The System Log window is as follows. Users can refresh the error logs by clicking Refresh, and clear the 
error logs in the window and the CPU module by clicking Clear. 
 
 
  Rack number & Slot number: If errors are generated by extension modules, the racks and the slots on 
which the extension modules are installed are recorded in these 
columns. If no rack number and no slot number are recorded, it means 
that an error occurs in a CPU module.   
  Module ID: The IDs of CPU modules, or those of extension modules 
  Error Code: The error codes for error logs 
  Date & Time: The time when errors occur 
The newer error log is exhibited in the upper row.   
  The description related to an error log is in the last field.