Siemens SIMATIC S7-1200 CP 1243-8 IRC Operating Instructions Manual page 78

Configuration
4.8 Ethernet interface
● Monitoring time for S and U frames (t
Monitoring time in seconds for the acknowledgment of data frames of the master by the
CP.
After receiving data from the master, the CP acknowledges the received data as follows:
– If the CP sends data to the master itself within t
– The CP sends an acknowledgment frame (S format) to the master of the latest when t
Permitted range: 1 ... 255
Default setting: 10
The value of t
● Idle time for test frames (t
Monitoring time in seconds during which the CP has not received any frames from the
master.
When t
This parameter is intended for situations in which longer idle periods occur; in other
words, times when there is no data traffic.
Permitted range: 1 ... 255
Default setting: 30
● Difference between send sequence number N(S) and receive sequence number N(R) (k)
The difference between the send sequence number and receive sequence number of a
frame.
The master returns the send sequence number of a frame from the CP that the sending
CP then saves as the receive sequence number. Frames whose send sequence number
is lower than the receive sequence number after the difference configured here is added
are evaluated as having been successfully transferred and are deleted from the send
buffer of the CP.
Permitted range: 1 ... 64
Default setting: 12
● Max. number of unacknowledged data frames (w)
w: Maximum number of received data frames (I-APDUs), after which the oldest frame
received from the master must be acknowledged.
Permitted range: 1..8
Default setting: 8
The value must be less than the value of "Difference between send and receive
sequence number" (k).
78
received from the master during t
format).
elapses.
should be less than that of t
2
3
elapses, the CP sends a test/control frame (U format) to the master.
3
)
2
at the same time along with the sent data frame (I
2
.
1
)
Operating Instructions, 02/2018, C79000-G8976-C385-03
, it acknowledges the data frames
2
2
CP 1243-8 IRC