Rockwell Automation T8110B/T8110 Trusted TMR Processor - Manual (Page 34)

Trusted
TM
TMR Processor T8110B/T8110
Issue 18 Feb 08 PD-T8110B/T8110 34
5. Fault Finding and Maintenance
5.1. Testing and Diagnostics
The Trusted TM TMR Processor provides fault monitoring, self test and diagnostics functions for the
Trusted TM TMR processing sub-system.
Periodic hardware tests are carried out on the microprocessors, memory management units, clock
devices and communications busses.
The Trusted TM TMR Processor’s error detection logic is tested periodically to ensure its continued
correct operation. Testing is performed using hardware and software self-tests that are automatically
scheduled by the module’s real-time operating system.
The results of all testing are stored in a log for uploading to an Engineering Workstation.
The module’s ‘Maintenance’ mode provides all of the functionality available during the ‘Run’ mode, with
provision to download application programs.
In the Maintenance mode, the Engineering Workstation is allowed to modify user programs and re-
program the module.
The Trusted TM TMR Processor has an RS232 serial diagnostics port and front panel indicators to aid
module fault diagnosis.
The diagnostics port has a serial data rate of 19k2 bits/s and is used to interface the Engineering
Workstation to the Trusted
TM TMR Processor.
5.2. Faults
In the event of a second processor board failure occurring, the Trusted TM TMR Processor is isolated
automatically from the remaining system operation. External interfaces are held in their default
condition, except where the interface is used for fault and diagnostic information. Where possible,
information indicating the source/cause of failure is retained in the non-volatile memory. A fault reset
command can be initiated either by the front panel Reset push-button or from the Engineering
Workstation.
In an active/standby configuration (Companion Slot), on the first processor slice board failure an
active/standby Trusted
TM TMR Processor changeover will occur automatically providing the
prerequisites have been met as described in the next section.
The power fail signals provide early notification of an impending supply failure, if this arises the
Trusted
TM TMR Processor goes into the ‘Power Off’ mode.
System data, fault information and user program data are retained in the Trusted TM TMR Processor
non-volatile memory during ‘Power Off’ mode. User program data (such as internal and plant status
information) is available to the user programs in ‘On-Line’ and ‘Test and Load’ modes.