RSTP Bridge Configuration

About RSTP

Use to design a network with redundant cabling so that Ethernet communication automatically finds an alternate path if a communication disruption occurs (for example, a cable breaks or a device becomes inoperable). This method does not require you to manually enable or disable communication paths.

Changing these parameters can affect sub-ring diagnostics, I/O , and network recovery times.

Access the RSTP Tab

You can access the RSTP parameters in Control Expert by double-clicking the 140CRA31908 module in the Control Expert rack view.

Parameters

This table shows the Bridge priority parameters for the RSTP Operational State on the RSTP tab:

Bridge Priority	Value	CPU	140CRA31908
Root	0	default	—
Backup Root	4096	for redundant configurations (automatic)	—
Participant	32768	—	default
NOTE: In redundant systems, the RSTP bridge priority is applied to the CPU module in rack A.

Cable Redundancy

Use a daisy chain loop configuration that implements the RSTP service to establish redundant communications between the 140CRA31908 module and an EIO scanner. The module operates normally when at least one of the two physical paths to the 140CRA31908 is valid.

determinism

For a defined application and architecture, you can predict that the delay between an event (change of value of an input) and the corresponding change of a controller output is a finite time t, smaller than the deadline required by your process.

adapter

An adapter is the target of real-time I/O data connection requests from scanners. It cannot send or receive real-time I/O data unless it is configured to do so by a scanner, and it does not store or originate the data communications parameters necessary to establish the connection. An adapter accepts explicit message requests (connected and unconnected) from other devices.