Toshiba GRZ100 B Series, Instruction Manual

Page: 258 / 447

⎯
257
⎯
6 F 2 S 0 8 4 6
6.7 Maintenance
6.7.1 Regular Testing
The relay is almost completely self-supervised. The circuits which can not be supervised are
binary input and output circuits and human interfaces.
Therefore regular testing can be minimized to checking the unsupervised circuits. The test
procedures are the same as described in Sections 6.4.1, 6.4.2 and 6.4.3.
6.7.2 Failure Tracing and Repair
Failures will be detected by automatic supervision or regular testing.
When a failure is detected by supervision, a remote alarm is issued with the binary output signal of
FAIL (*) and the failure is indicated on the front panel with LED indicators or LCD display. It is
also recorded in the event record.
(*) Failure signals on the external circuits, that is signaling channel, VT circuit and isolator circuit,
can be allotted to any of the binary output relays by the user. Failure signals of the signaling
channel and VT circuit are set to BO12 of the IO module as the default setting.
Failures detected by supervision are traced by checking the "Auto-supervision" screen on the
LCD.
If any messages are shown on the LCD, the failed module or failed external circuits can be located
by referring to the Table 6.7.2.1.
This table shows the relationship between message displayed on the LCD and estimated failure
location. The location marked with (1) has a higher probability than the location marked with (2).
As shown in the table, some of the messages cannot identify the fault location definitely but
suggest plural possible failure locations. In these cases, the failure location is identified by
replacing the suggested failed modules with spare modules one by one or investigating and
restoring the monitored external circuits (that is signaling channel, VT circuit and isolator circuit)
until the "Alarm" LED is turned off.
The replacement or investigation should be performed first for the module or circuit with higher
probability in the table.
If there is a failure and the LCD is not working such as a screen is frozen or not displayed, the
failure location is any one of SPM and HMI module.