Fatal errors result in a reset of the affected CSLS. The evidence of a fatal error occurrence changes based on the time since the fatal error occurred. Immediately after a fatal error the CSLS unit resets and begins its power-up testing, which completes in about one minute. During this time the CSLS unit is not reporting diagnostic information to the DeltaV controller. A redundant partner of this CSLS unit indicates that its partner is not available while it is power-up testing. If the fatal error is transient, the partner not available condition clears when power-up testing is complete. But if the fatal error is persistent, the partner not available condition remains.
The CSLS unit stores the reason for a fatal error in a diagnostic parameter called PAST_ERROR (PastError in Diagnostics Explorer). The value of PastError is updated when the CSLS unit finishes power-up testing following a reset due to a fatal error. Persistent fatal errors are expected to cause the same condition to be detected when the CSLS unit begins running its continuous diagnostic tests. The outcome is another reset. When a CSLS detects the same fatal error on two back-to-back resets, it enters a reduced startup state where SIS modules do not execute and outputs cannot be powered on. The CSLS unit reports non-zero PAST_ERROR and DiagStatus is Persistent Fatal Error After Powerup.
When a simplex CSLS is in reduced startup state it forwards PastError into FAILED alarm. Immediately after the fatal error is detected COMM alarm is posted, which becomes inactive when power-up tests complete. At that time FAILED alarm becomes active.
When a standby CSLS unit (in redundant CSLS) is in reduced startup state it reports its condition via MAINT alarm only since the active CSLS continues to operate. Immediately after the fatal error on standby CSLS is detected MAINT alarm (Standby CSLS is not communicating) is posted, which becomes inactive when power-up tests complete. At that time MAINT alarm (CSLS Not Fully Operational) becomes active.
When an active CSLS unit (in redundant CSLS) is in reduced startup state (with the standby CSLS unit either absent or in reduced startup mode as well) it forwards PastError into FAILED alarm. Immediately after the fatal error on active CSLS is detected COMM alarm is posted, which becomes inactive when power-up tests complete. At that time FAILED alarm becomes active.
Persistent fatal errors generally require a hardware repair. The hardware should be returned to Emerson for repair. Before returning the hardware, perform a manual reset of the affected CSLS unit using Diagnostics Explorer. If the error continues to be present after power-up tests complete, which is expected, please contact the Global Service Center (GSC) for technical support prior to contacting Customer Service for a Material Return Tracking (MRT) number. The GSC will help determine the necessary action and forward the call to Customer Service if needed. For contact information, visit:
http://www.emersonprocess.com/systems/support/ratecard.htm
The PastError parameter retains the reason for the most recent fatal error. PastError clears (returns to Good) the next time a reset occurs that is not due to an error condition, for example, a manual reset is done.