Attention – Atop Technology SE5404D User manual User Manual
Page 43
User manual Version 1.3
4-Port DIN-Rail Serial Device Server SE5404D
Copyright © 2011 Atop Technologies, Inc.
All rights reserved. Designed in Taiwan.
- 42 -
connection status by sending periodic “keep alive” packets. If the remote host does not respond to the packet within
the time specified in this field, the serial device server will force the existing TCP connection to close. If this setting
is set to 0,
the TCP connection will remain open even if there is no response to the “keep alive” packets.
Serial to Network Packet Delimiter
Packet delimiter is a way of packing data in the serial communication. It is designed to keep packets in track. Serial
device server provides three patterns in parameter setting: (1) packet delimiter by (1) Interval timeout, (2) Max
Byte and (3) Character pattern.
1.
By Time
– The device will transmit the serial data in its buffer when the specified time interval has
reached and no more serial data comes in.
2.
By Max Bytes
– The device will transmit the serial data when the data in the buffer has reached the
specified length.
3.
By Character - The device will transmit the serial data in its buffer when it sees the specified character.
If one or more of the delimiters are selected, data would be transmitted if any of the conditions are met.
Attention
Packet delimiter by Interval timeout
This parameter defines how large a gap in serial communication the serial device server
will allow before packing the serial data in its internal buffer for network transmission.
The optional “Internal timeout” transmit time depends on your application, but it must be
at least larger than one character interval within the specified baud rate. For example,
assume that the serial port is set to 1200 bps, 8 data bits, 1 stop bit, and no parity. In
this case, the total number of bits needed to send a character is 10 bits, and the time
required to transfer one character is (10 (bits) / 1200 (bits/s)) × 1000 (ms/s) = 8.3 ms.
Therefore, you should set the “Interval timeout” to be larger than 8.3 ms, so in this case,
it must be greater than or equal to 10 ms. If it is necessary to send a series of characters
in the same packet, the serial device will need to send that series of characters within
the specified transmit time, and the total length of data must be less than or equal to the
serial device server internal UART buffer size (4K per port).
Network to Serial Packet Delimiter
Network to Serial Packet Delimiter is used less often compared to Serial to Network Delimiter because Ethernet
has better speeds. Packet delimiter is a way of packing data in a serial communication. It is designed to keep
packets in track. Serial device server provides three patterns in parameter setting: (1) packet delimiter by (1)
Interval timeout, (2) Max Byte and (3) Character pattern.
1.
By Time
– The device will transmit the network data in its buffer when the specified time interval has
reached and no more network packet comes in.
2.
By Max Bytes
– The device will transmit the network data when the data in the buffer has reached the
specified length.
3.
By Character - The device will transmit the network data in its buffer when it sees the specified
character.
If one or more of the delimiters are selected, data would be transmitted if any of the conditions are met.