Using this register, the module transfers status information regarding sending and receiving readiness, data received and transmits frames data taken over to the superordinated system.
|
Bit |
Description |
|---|---|
|
0–2 |
0–7 = Consecutive receiver sequence number |
|
3 |
0 = Receiver connection establishment requested by module 1 = Receiver data exchange is enabled |
|
4–6 |
0–7 = Feedback transmitter sequence number |
|
7 |
0 = Transmitter connection establishment requested by module 1 = Transmitter data exchange is enabled |
Consecutive Receiver Transmitter Sequence Number
If data from the module are available, they are created in the Input MTU and the sequence for signaling to the superordinated system is increased. At default setting (also see Block Forward), a new sequence number with new data from the module is only put back into the Input MTU after this current number has been acknowledged by the OutputSequence. This is done to signal the module that the Input MTU was read out and may be overwritten. This counter is also increased to detect status changes in the area of the connection establishment or termination.
Receiver Connection Establishment / Data Exchange
With this status, the module signalizes whether the interface is activated for receiving or is synchronized with the superordinated system. The interface is ready for receiving only after the synchronization (also see Synchronization of the Sending and Receiving Readiness).
This status must be cyclically monitored, as in the case of transfer problems or noncompliance with the sequence acknowledgement also the module itself can disconnect the connection. If so, synchronization has to be repeated.
Feedback Transmitter Sequence Number
This is the feedback which sequence to be sent from the OutputSequence the module took over. Here, the module signalizes that the Output MTU has been read out and copied to the buffer and may be overwritten with new transmission data.
Transmit Connection Establishment / Data Exchange
This is the status feedback from the module that the sending direction is activated and synchronized (also see Synchronization of the Sending and Receiving Readiness).
Thus, data for the interface can be sent.
