Product manual

Maintenance, Test and maintenance software
Technical Product Manual - DCT1800-GAP
TD 92093 (1/LZBNB 103 108 R4D) / 2006-03-09/ Ver.C
© 2006
6
2.2.1 Diagnostics
After T&M has concluded that the message is not info but a fault message, T&M starts to decode,
locate and verify the fault. This is done by the diagnostics module. After verification, T&M will isolate
the faulty circuit to prevent usage of it by the system. This is done by changing its status temporarily
to Test ModE (TME). When the fault cannot be found during testing, the fault message in the fault
table will be completed with the status code C (cleared). This indicates the occurrence of a soft fault.
2.2.2 Fault counters
After verification of the fault, T&M knows exactly what type of fault occurred and where. A fault counter
for this fault will be incremented. When the fault counter exceeds its threshold value, no further
measures are taken, but immediately a general alarm will be activated with fault code 3 and the status
of the board or base station is set to malfunctioning. The function of the fault counter is to count faults
that can be cleared by maintenance, see paragraph
2.2.3, but continue to re-appear, i.e. soft faults.
When too many of these ‘intermittent faults’ are counted within a specific time limit, an alarm shall be
raised. The fault counter is halved every 24 hours, to avoid generation of alarms when intermittent
faults only occur occasionally.
2.2.3 Maintenance
If the fault counter is not exceeding its limits, T&M will now try to correct the error by resetting the
circuit or board. This is called a T&M reset. This reset causes the circuit or board to start a self test.
When the fault is cleared after this, the fault is an intermittent one. T&M will release the circuit by
changing its state to available (AVE). In the fault table the fault message will be completed with the
status code R (released).
When the fault returns after the test, the fault is persistent. T&M will take the circuit out of service by
changing its state to malfunctioning, MFG, and raise an alarm. This alarm is called a general alarm.
A general alarm means that:
• The general alarm relay on the MCCB is activated.
• A service message appears in CSM Windows.
• A fault report is written in the service table.
• The fault message in fault table is completed with the status code S (service).
• The faulty circuit or board is set to MFG.
It should be noted that service is only required when a general alarm occurs. For those faults where
a message is only written in info and fault tables, no service is required because the system is not
malfunctioning yet. The service table is represented in CSM Windows in the Service Messages
window.
2.2.4 Error tables
The three different error tables, as indicated above are:
• Info table
• Fault table
• Service table
The info and fault tables are meant for DCT1800-GAP system support specialists. The service table
is meant for field service technicians.