Technical data

R911305038 / 01 | Rexroth VCP-Operating Concept Electric Drives and Controls | Bosch Rexroth AG 5-121
Standard Mode
5.13.4 Liveness Flag
In some communication protocols, you cannot control the operability of
the interface in the controller. The Liveness flag has been developed
to address this shortfall. This is a simple function, which has proven
very effective in practice.
Whenever the controller needs to know whether the connection is still
active, it writes a logical 1, and subsequently a logical 0, to bit 3 of the
Write Coordination byte.
The operating device constantly monitors the Liveness flag in the Write
Coordination byte and compares it with the status of the Liveness flag
in the Read Coordination byte. As soon as the two bytes are no longer
the same, the operating device copies bit 3 from the Write Coordination
byte to the Read Coordination byte.
Within a timeout time, the controller must now also check whether both
statuses are identical.
5.13.5 Data Set Download Active
As soon as the operating device transfers a data set to the controller, it
writes a logical 1 to the Data Set Download Active bit. After all data
were sent, the operating device writes a logical 0 to the Data Set
Download Active bit. The controller can now work with the new data set
values.
5.14 Write Coordination Byte
The term Write Coordination byte indicates that the controller writes
this byte.
The Write Coordination byte is only read by the operating device. This
byte is used together with the Read Coordination byte for the hand-
shake and data coordination with the controller.
Here, the controller indicates its current status to the operating device.
When you determine the timeout time, remember to take the transfer
times and polling times into account.