Mitsubishi QJ71MT91 User Manual page 101

7 PARAMETER SETTING
7.2.2 TCP/UDP/IP setting
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(1) TCP/UDP/IP monitoring timer
(a) TCP ULP timer value
1) Set the ACK monitoring time for opening TCP connection and sending
data. If no ACK has been received from the target device for a
predetermined period of time, the connection is forcibly closed.
2) No setting is required when the default value is used.
(b) TCP zero window timer value
1) The window indicates the receive buffer on the receiving side.
2) When the receive buffer on the receiving side becomes full (window
size = 0), data transmission is held until the receive buffer has free
space.
In such a case, the sender sends a window check packet to the
receiver according to the TCP zero window timer value to check
whether data can be received or not.
3) No setting is required when the default value is used.
(c) TCP resend timer value
1) Set the resend time for the case where ACK is not returned when TCP
connection is opened and TCP data are transmitted. This timer is also
used for the time for resending an ARP request in the case where a
response is not returned in reply to the sent ARP request. (ARP is
resent at the TCP resend timer value/2.)
2) No setting is required when the default value is used.
(d) TCP end timer value
1) When TCP connection is closed from the local station, the local station
sends FIN to the target device, and receives ACK and then FIN from
the target device. Set the monitoring time for which the station will wait
for FIN from the target device.
2) If FIN is not received from the target device when the TCP end timer is
expired, RST is sent to the target device, forcing the connection to
close.
3) No setting is required when the default value is used.
(e) IP reassembly timer value
1) In data communications, a block of data may be split into segments on
an IP level due to the send/receive station buffer limitations.
2) Set the time for waiting for the next split data segment in the case
where the QJ71MT91 receives and restores the split data.
3) No setting is required when the initial value is used.
MELSEC-Q
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