W&T Com-Server++, Manual

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84
W&T
Packetizing serial datagrams
10�1�2 Startse Lengthfield
The Com-Server sends the datagram after reception of a Start
Sequence and evaluation of a length specification contained in
the datagram.
n
Activate this Packet Option (Telnet)
Activates the selected option for serial data reception.
n
Start Sequence Size
Enter the length of the Start Sequence in bytes. The max.
Length is 3.
n
Start Sequence
Hexadecimal, space-delimited byte sequence of the re-
spective
Start Sequence . The input field is only activated if
the sequence size was previously specified and sent to the
Com-Server.
n
Length Field Offset
Start position of the length field within the serial datagram
in bytes. Counting method beginning with 0.
n
Size
Length of the length field in bytes. In the protocol field de-
fined by
Length Field Offset , Size and Byte Order , the Com-
Server expects specification of the total length of the serial
datagram, including any
Start Sequence and appended
checksum. If the length specification is defined differently
within the serial protocol, a corresponding correction may
be needed using the
Additional Bytes option.
1 Clean network-side packetizing is only assured if
the serial datagrams do not exceed the MTU of the
Com-Server. The factory default setting for this is 560
bytes. In the menu path Setup System
r
Setup TCP/IP
r
MTU this can be extended to 1024 bytes.