Chapter 3. CPU ConfigurationGFK-2222AD April 2018 1233.2.7 Fault ParametersYou can configure each fault action to be either diagnostic or fatal.A diagnostic fault does not stop the PLC from executing logic. It sets a diagnostic variable and islogged in a fault table.A fatal fault transitions the PLC to the Stop Faulted mode. It also sets a diagnostic variable and islogged in a fault table.Fault ParametersLoss of or MissingRack(Fault group 1.) When BRM failure or loss of power loses a rack or when a configured rackis missing, system variable #LOS_RCK (%SA12) turns ON.(To turn it OFF, fix the hardware problem and cycle power on the rack.)Default: Diagnostic.Loss of or MissingI/O Controller(Fault group 2.) When a Bus Controller stops communicating with the PLC or when aconfigured Bus Controller is missing, system variable #LOS_IOC (%SA13) turns ON.(To turn it OFF, replace the module and cycle power on the rack containing the module.)Default: Diagnostic.Loss of or MissingI/O Module(Fault group 3.) When an I/O module stops communicating with the PLC CPU or aconfigured module is missing, system variable #LOS_IOM (%SA14) turns ON.(To turn it OFF, replace the module and cycle power on the rack containing the module.)Default: Diagnostic.Loss of or MissingOption Module(Fault group 4.) When an option module stops communicating with the PLC CPU or aconfigured option module is missing, system variable #LOS_SIO (%SA15) turns ON.(To turn it OFF, replace the module and cycle power on the rack containing the module.)Default: Diagnostic.System Bus Error (Fault group 12.) When a bus error occurs on the backplane, system variable #SBUS_ER(%SA32) turns ON.(To turn it OFF, cycle power on the main rack.)Default: Fatal.I/O Controller orI/O Bus Fault(Fault group 9.) When a Bus Controller reports a bus fault, a global memory fault, or anIOC hardware fault, system variable #IOC_FLT (%SA22) turns ON.(To turn it OFF, cycle power on the rack containing the module when the configurationmatches the hardware after a download.)Default: Diagnostic.SystemConfigurationMismatch(Fault group 11.) When a configuration mismatch is detected during system power-up orduring a download of the configuration, system variable #CFG_MM (%SA9) turns ON.(To turn it OFF, power up the PLC when no mismatches are present or download aconfiguration that matches the hardware.)This parameter determines the fault action when the CPU is not running. If a systemconfiguration mismatch occurs when the CPU is in RUN Mode, the fault action will beDiagnostic. This prevents the running CPU from going to STOP/FAULT mode. To overridethis behavior, see Configuring the CPU to Stop Upon the Loss of a Critical Module.Default: Fatal.Fan Kit Failure (Fault group 0x17.) When a fault is detected in the Smart Fan kit, system variable#FAN_FLT (%SA7) turns ON.(To turn a fan kit fault OFF, clear the Controller fault table or reset the PLC.)Default: Diagnostic.
