The BMENOR2200H module is equipped with a
dual-bus connector that supports both Ethernet and X Bus communications.
This Ethernet backplane port is used mainly to communicate with the remote master or outstations with RTU protocols. The backplane interface is used to communicate with the CPU. The main activity of the backplane interface is the synchronization of data between CPU registers and the RTU point database inside the module. The synchronization cycle can be one or more PLC application scan cycles, depending on the data amount and backplane load.
When the Master Channel Receives Events from the Sub Slave
When something significant changes in the sub slave (like the value of a point), the sub slave sends an event. The system receives this event and the event is then routed to a SCADA system, as shown in this example:
1
The sub slave sends events to the master channel of the BMENOR2200H module.
2
The master channel updates the point values in the module and the database of the logic outstation channel and synchronizes the value to CPU registers.
3
Events are routed to outstation channels according to point configuration.
4
The outstation channel buffers these events and sends events to SCADA when the communication link is established.
When the Outstation Channel Receives Request from SCADA
In the RTU system, a SCADA system sends requests (commands) like an Integrity Poll to the outstations connected to it. The outstation channel receives this request and sends a response to the SCADA system. With event routing, the behavior of the outstation channel is exactly the same as a standalone (no event routing) outstation channel. The master channel and sub slaves are not involved in this case.
This sample illustration shows a request from a SCADA system:
1
The SCADA system sends an Integrity Poll request to the outstation channel.
2
The point values are synchronized cyclically between the database of the outstation channel and CPU registers.
3
The outstation channel responds to the SCADA request with the point values in the database.
When the Master Channel Sends Request to the Sub Slave
The master channel can send requests to a sub slave connected to it, and a sub slave sends the response back to the master channel. The behavior of the master channel in this case is exactly the same as a standalone master channel. The points in the logic outstation channel should be synchronized with the updated point in the master channel.
Send request to a sub slave example:
1
The application in the M580 CPU sends an Integrity Poll command to the master channel.
2
The master channel sends Integrity Poll requests to the sub slave.
3
The sub slave responds to the request with the value of the latest points.
4
The logic slave data base is synchronized while the master channel updates the database.
NOTE: Point values are synchronized cyclically between the database of the master channel and CPU registers.
