ABB REF 542plus, Operator'S Manual, Page: 118 / 134

The fault can be signalled externally via the following mechanism:
*
HMI LEDs
*
Ready:
*
Black
Protection and control functions not active
*
Green
Protection and control functions active
*
Network communication:
*
Black
No communication
*
Green
Communication works properly
*
Amber
Some communication error on the line (handled only by MODBUS and
ETHERNET module)
*
Red
Communication error
*
Alarm Led and Interlocking errors are handled by the programmable logics
*
HMI error message
If an error message has been displayed in the MMI, no other message is
displayed until:
*
a local/remote reset command has been given
*
completion of a configuration download
*
SPA event
Supervision by bootloader
REF 542plus has an on-chip bootloader that handles the software upgrade and the
entering into Factory test mode. The bootloader supervises RAM (Random Access
Memory) and FLASH (MC non-volatile memory) application program correctness.
At normal start-up, it performs a simple RAM test that verifies the presence of the
RAM chip and its memory size. The exhaustive RAM test has to be performed if the
Factory test mode is activated.
If the RAM test is passed, the bootloader verifies the presence and the correctness of
the application program which is stored in FLASH. The presence is verified through
a pre-defined pattern check in a fixed FLASH location and the correctness is
verified through application program checksum calculation.
The following table presents the bootloader fault descriptions:
118
REF 542plus REF 542plus
Multifunction Protection and Switchgear Control Unit
Operator's manual
1MRS755869