Using this register, command information regarding the sending and receiving readiness, the takeover of received data, and the frames to be sent is transferred to the module.
|
Bit |
Description |
|---|---|
|
0-2 |
0–7 = Consecutive transmitter sequence number |
|
3 |
0 = Transmitter connection establishment requested by module 1 = Transmitter data exchange is enabled |
|
4-6 |
0–7 = Feedback receiver sequence number |
|
7 |
0 = Receiver connection establishment requested by module 1 = Receiver data exchange is enabled |
If transmission data for the module is available, these can be created in the Output MTU and the sequence for signaling to the module can be increased. A new sequence number with new data may only be placed in the Output MTU after this current number has been acknowledged as read out by the InputSequence of the module. Here, an unacknowledged Block Forward of MTU blocks (how configuration has to take place in input direction) is automatically possible. However, it is a requirement that each sequence can be read and evaluated by the module, as otherwise a correct procedure of data transfer and sequence acknowledgement is not possible. This must be kept in mind for different cycle times of the involved components. However, the total number of blocks must not exceed 7, as otherwise a clear monitoring of the feedback transmitter sequence number is not possible.
This is the status message and, at the same time, a command information for the module that the sending direction is active and synchronized. If sending data from the module buffer is desired, this bit must remain set. Disconnecting the connection can be performed by deleting this bit. The frames in the transmit buffer that have already been transferred are still sent, incomplete data frames are discarded. To establish a new connection, synchronization has to be repeated.
This is the message to the module indicating, which received sequence from the InputSequence was taken over. Here, the module is signalized that the Input MTU has been read out and that the module may overwrite it with new received data. This sequence must also be adhered to with activated Block Forward.
This is the status message and, at the same time, a command information to the module indicating that the receive direction is active and synchronized. If receiving data by the superordinated system is desired, this bit must remain set. Disconnecting the connection can be performed by deleting this bit.
The data bytes that are still located in the receive buffer and have not yet been transferred are deleted. To establish a new connection, synchronization has to be repeated.