DIAGNOSTICS
The system with active Control Unit possesses three different diagnostics levels which make it possible to lo
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cate any faults:
level 1
During system start-up the green RUN led of the module on which the fault occurs
(RBC2 or SCC2) flashes emitting a light code referring to the type of fault.
In general the Control Unit modules have special leds for showing correct operation or
faults and their meaning is described for each individual module in the CONTROL UNIT
paragraph of this chapter.
level 2
During system start-up, when the programming terminal display shows the system di
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agnostic tests a hexadecimal code is emitted which indicates the fault.
level 3
During normal system operation the programming terminal display shows an error mes
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sage (decimal number plus alarm meaning) which describes the type of fault.
Below is a description of the tests when the system is switched on and the diagnostic levels.
TESTS WHEN SYSTEM IS SWITCHED ON
Diagnostics at system switch on:
·
GCSR test: before starting the tests on another board, it makes sure that the interprocessor communica
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tion registers are working properly.
· CPU test: checks the address modes and instructions of microprocessor 68020.
· ROM checksum: checks that the checksum on the BootROM is correct.
· RAM test: checks each single word of the local and shared RAM. It is not a destructive test as it stores
and recovers the original contents of the RAM. The shared RAM is checked from every board to verify
that it can be accessed by all boards.
· Timer test: checks the interval timers for accurate synchronisation.
· UART test: checks the UART’s (serial ports) in local loopback mode.
·
Fence register: checks that the memory protection characteristic is working properly.
·
Image register: applied to the PLC board or Robot CPU if the PLC board is not present. It checks the
special characteristics of the RAM region concerning the image of the shared RAM.
·
DSP test: only on the Servo CPU boards, checks operation of the DSP chip and the relevant high speed
RAM.
DIAGNOSTIC LEVEL 1
LED CODES
If a diagnostic result is negative or if a fault occurs that inhibits the system start-up sequence, the green RUN
LED of the board on which the fault has occurred will begin to flash. The sequence of pauses and flashes
given below is always the same while the number of flashes of the LED varies according to the type of prob
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lem. The sequence is the following:
1. Long pause (3 seconds)
2. Primary code
3. Medium pause (1.5 seconds)
4. Secondary code
5. Code repetition, a long pause is repeated.
C3G Plus MAINTENANCE
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diagnostic
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