Rockwell Automation T80017 Application Note Regent to Trusted Migration - Manual (Page 6)

Trusted TM
AN-T80017 Regent to Trusted Migration
Issue 2 June 08 AN-T80017 6
3. Installation
Both the Regent and Trusted are 3-2-0 degradation systems. When fully healthy, all three slices are
working (3). On one fault, the remaining two slices can continue operating as long as they agree (2).
On a fault in one of the two remaining slices, the system shuts down (0).
This provides higher integrity than 3-2-1-0 since at least two system slices must be operational for the
system to be operational, allowing instant and robust diagnostics through voted comparison. However,
since each system requires two of the three slices to operate, an online changeover is not possible and
the changeover must be made with the system in shutdown.
The new Trusted chassis may be fitted in place of an existing rack-mounted Regent+Plus processor
chassis if time is available for physical installation, or it may be fitted in spare space nearby whilst the
existing system is operating. The standard TC-321-01 cable is 4 metres long, but the existing Regent
Safetybus cables to the Regent processor chassis may also have slack inside trunking, or it may be
possible to route them differently to gain length.
Power the Regent I/O chassis first and allow them to start. Then power the Trusted processor chassis
with the Safetybus connected. If the Trusted application and system.INI are correct, the application will
start and the application can be commissioned.