ICS TRIPLEX TC-303-01-2M0 Trusted Communications Cables

Data is transferred between the TMR Processor and the Communications Interfaces using a

common interface called the Network Variable Manager. When data is read from a Trusted

System, the data is obtained from the local copy maintained on the Communications

Interface, providing a fast response.

Data writes are more complicated. If a data write simply updated the local copy and was

then relayed to the processor, the other Communications Interfaces in the system would

carry different data. This may cause problems for redundant links.

To overcome this problem, when data is written to a Communications Interface, it is first

passed to the TMR Processor and the write is acknowledged immediately by the

Communications Interface (to avoid communications delays). The processor updates its own

database and then sends the data back to all Communications Interfaces so that they all

have the same data. This can take one or two application scans. This means that subsequent

reads will receive the old data immediately after the write, until the new data has been

distributed.

All changes to CI parameters (.ini changes) loaded online do not require a power cycle, and

will take effect immediately. The Communications Interface disconnects all communications

and restarts. Communications is also restarted on an application online update and is shut

down when the application is stopped.

user-configurable module providing overall system control and monitoring facilities and processes

input and output data received from a variety of analogue and digital Input / Output (I/O) modules

across a Trusted TMR Inter-Module Communications Bus.

The range of applications for the Trusted TMR Processor vary in integrity level and include fire and

gas control, emergency shutdown, monitoring and control, and turbine control.