Rockwell Automation T8432 Trusted Dual Vdc Analogue Input Module - 60 Channel - Manual (Page 27)

Trusted
TM
Module T8432
Issue 16 Apr 10 PD-T8432 27
5. Fault Finding and Maintenance
5.1. Fault Reporting
Input module faults are reported to the user through visual indicators (LEDs) on the front
panel of the module. Faults are also reported via status variables which may be
automatically monitored in the application programs, and external system communications
interfaces. There are generally two types of faults that must be remedied by the user;
external wiring and module faults. External wiring faults require corrective action in the field
to repair the fault condition. Module faults require replacement of the input module.
5.2. Field Wiring Faults
The input circuits of the module may be used to detect field wiring faults in addition to alarm states. To
achieve this, line monitoring components must be fitted to the field device.
By comparing the input signal from the field with pre-configured alarm thresholds, the module can
automatically detect field-wiring faults. When a field loop develops a line fault, the corresponding input
state will be reported and the line fault status for that channel will be set to ‘1’. All other input channels
will be unaffected, except in the case of common cause wiring faults in the field.
Once the field-wiring fault has been identified and corrected, the input status and the input status LED
will display the normal status of the field device and field wiring.
5.3. Module Faults
Extensive diagnostics provide the automatic detection of module faults. The 1-oo-2D Dual architecture
of the input module and the diagnostics performed ensure the validity of all critical circuits. Using the 1-
oo-2D Dual architecture provides a fault tolerant method to withstand the first fault occurrence on the
module and continue normal input measurements without interruption in the system or process. Faults
are reported to the user through the Healthy status indicators on the front panel of the module and
through the INFO and HKEEPING variables. Under normal operations all three Healthy Indicators are
green. When a fault occurs, one of the Healthy LEDs will flash red. It is recommended that this
condition is investigated and if the cause is within the module, it should be replaced.
Module replacement activities depend on the type of spare module configuration chosen when the
system was configured and installed. The module may be configured with a dedicated Companion Slot
or with a SmartSlot for a spare replacement module.