ABB REF 542plus Operator's Manual page 119

1MRS755869
Multifunction Protection and Switchgear Control Unit
Operator's manual
Faults/Errors
RAM presence
RAM size
FLASH application
program
Reset
REF 542plus performs a complete and deep analysis of the last reset cause. The
reset can be the result of a normal situation or a HW/SW fault detection. A normal
situation can be either of the following two:
Power-switch cycle
*
REF 542plus power is switched OFF and than ON.
Commissioning test end
*
REF 542plus is in commissioning test mode and the user exits from the
commissioning test HMI menu.
The fault situations consist of the following:
HW watchdog
*
A HW watchdog supervises the SW execution. The required refresh time is about
80 ms (fault-time detection). This is the worst reset cause because the reset is
beyond SW control which means that the real fault root cause in principle is
unknown. The cause can be either SW or HW related and in any case there is no
possibility to obtain a SW reference or description of the fault. The fault analysis
depends on the fault reproducibility in laboratory. If the fault is not reproducible,
a special REF 542plus SW can be built that is able to make a trace log of all the
activities executed by the SW (interrupts, tasks switching, events, semaphore,
etc.). This trace log is stored in the internal memory and can be displayed in the
DEBUG port after a watchdog reset. The trace log contains the last operation
performed by the system before the fault and it can be the starting point for
further analysis to identify the real fault cause. That is, if the fault was HW or
SW related, and, in case of SW, in which SW module the fault occurred or what
sequence of events that produced the fault.
SW exceptions
*
The internal processor supervises all instruction executions and memory access
instances. In case it detects an exception, it prepares an exception stack frame
and raises a SW exception interrupt. The REF 542plus exception handler stores
all the information contained in the exception stack frame in the internal memory
and sets the reset cause to SW exception. The SW exception always produces a
HW reset. At start-up, the SW exception is signalled through a HMI and SPA
event.
Signalling
DEBUG port message
"RAM error has been detected"
DEBUG port message
"RAM error has been detected"
"RAM addressing error (?) - size too small: xx"
DEBUG port message
"No valid application found - card resetting"
REF 542plus REF 542plus
Level
2
2
2
119