Moxa Technologies 5400 - Manual (Page 40)

Force Transmit
Setting Factory Default Necessity
0 to 65535 ms 0 ms Optional
0: Disable the force transmit timeout.
1 to 65535: Forces the NPort’s TCP/IP protocol software to try to pack serial data received during the
specified time into the same data frame.
This parameter defines the time interval during which NPort fetches the serial data from it’s internal
buffer. If data is incoming through the serial port, NPort stores the data in the internal buffer. NPort
transmits data stored in the buffer via TCP/IP, but only if the internal buffer is full or if the force
transmit time interval reaches the time specified under Force Transmit timeout.
Optimal force transmit timeout differs according to 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 Force Transmit timeout to be larger than 8.3 ms. Force Transmit timeout is
specified in milliseconds and must be larger than 10 ms.
If the user wants to send the series of characters in a packet, the serial device attached to NPort should
send characters without time delay larger than Force Transmit timeout between characters and the
total length of data must be smaller than or equal to NPort’s internal buffer size. The serial
communication buffer size of NPort is 1 Kbytes per port.
TCP Server Mode
NPort 5400 Series User’s Manual 5-14