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When it receives the data frame, the master sends the send sequence number from this or
(if several data frames are received) the last data frame as an acknowledgement to the RTU.
The RTU saves the send sequence number returned by the master as a receive sequence
number and uses it as an acknowledgement.
Data frames whose send sequence number is equal to or lower than the current receive
sequence number are evaluated as having been successfully transferred and are deleted
from the send buffer of the RTU.
Recommendations of the specification:
w should not be higher than 2/3 of k.
Recommended value for k: 12
Recommended value for w: 8
4.20.6
Data points
In the table "Data points" all configured tags are shown as data points grouped according to
tag types.
● Data points for the read direction
– Digital inputs
– Analog inputs
– Counter inputs
● Data points for the write direction
For the values that the communications partner writes in the process direction, the
following tag types are available:
– Digital outputs
– Aanalog memory bits configured as an analog value.
Analog memory bits configured as counters cannot be written.
The data points of the protocols TeleControl Basic, ST7 and "IEC" can be used both in the
read direction (in) and the write direction (out).
RTU3030C
Operating Instructions, 09/2017, C79000-G8976-C382-04
Apart from the configured process tags, here you will find two status tags for error
messages (STATUS_ERROR) and for the operating status of the RTU
(STATUS_RUN) that can be read by the communications partner.
These are event counters (DI0 and/or DI1) and analog memory bits configured as
counters.
Here you will also find the status bit for the next communication cycle
(NEXT_COM_CYCLE).
Configuration (WBM)
4.20 Telecontrol
183
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