Moxa Technologies OnCell G3111-HSPA series, Руководство пользователя

Страница: 50 / 127

OnCell G3111/G3151-HSPA Series Configuring Serial Port Operation Modes
7-9
Force transmit (default=0 ms): This parameter defines how large a gap in serial communication the OnCell
G3111/G3151-HSPA will allow before packing the serial data in its internal buffer for network transmission.
As data is received through the serial port, it is stored by the OnCell G3111/G3151-HSPA in the internal buffer.
The OnCell G3111/G3151-HSPA transmits data stored in the buffer via TCP/IP, but only when the internal
buffer is full or as specified by the force transmit time. When set to 0, the force transmit time is disabled, and
transmission is determined solely by the data in the internal buffer. At 1 to 65535, the TCP/IP protocol software
will pack the serial data received after there is a gap in serial communication that exceeds the specified force
transmit time.
The optimal force transmit time depends on your application, but it must be at least larger than one character
interval within the specified baudrate. 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 force transmit time 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 force transmit time, and the total length of data must be less than or equal
to the OnCell G3111/G3151-HSPA’s internal buffer size (1 KB per port).
Socket Applications
TCP Server Mode
TCP alive check time (default=7 min): This field specifies how long the OnCell G3111/G3151-HSPA will wait
for a response to “keep alive” packets before closing the TCP connection. The OnCell G3111/G3151-HSPA
checks 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 OnCell G3111/G3151-HSPA will force the existing TCP
connection to close. For socket and device control modes, the OnCell G3111/G3151-HSPA will listen for another
TCP connection from another host after closing the connection. If
TCP alive check time is set to 0, the TCP
connection will remain open even if there is no response to the “keep alive” packets.