OnCell G3100 Series Configuring Serial Port Operation Modes
Packet length (default=0): The Packet length setting refers to the maximum amount of data that is allowed
to accumulate in the serial port buffer before sending. At the default of 0 for packet length, no maximum
amount is specified and data in the buffer will be sent as specified by the delimiter settings or when the buffer
is full. When a packet length between 1 and 1024 bytes is specified, data in the buffer will be sent as soon it
reaches the specified length.
Delimiter 1 and Delimiter 2 (default=None): When Delimiter 1 is enabled, the serial port will clear the buffer
and send the data to the Ethernet port when a specific character, entered in hex format, is received. A second
delimiter character may be enabled and specified in the Delimiter 2 field, so that both characters act as the
delimiter to indicate when data should be sent.
ATTENTION
In order to enable a delimiter, packet length must be set to 0. Delimiter 2 should
only be enabled in
conjunction with Delimiter 1 and never on its own; otherwise there may be data errors. Even when a delimiter
is enabled, the OnCell G3100 will still pack and send the data when the amount of data exceeds 1 KB.
Delimiter process (default=Do Nothing): The Delimiter process field determines how the data is handled
when a delimiter is received. Delimiter 1 must be enabled for this field to have effect. If Delimiters 1 and 2 are
both enabled, both characters must be received for the delimiter process to take place.
• Do Nothing: Data in the buffer will be transmitted when the delimiter is received.
• Delimiter + 1: Data in the buffer will be transmitted after 1 additional byte is received following the
delimiter.
• Delimiter + 2: Data in the buffer will be transmitted after 2 additional bytes are received following the
delimiter.
• Strip Delimiter: Data in the buffer is first stripped of the delimiter before being transmitted.
Force transmit (default=0 ms): This parameter defines how large a gap in serial communication the OnCell
G3100 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 G3100 in the internal buffer. The OnCell
G3100 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 G3100’s internal buffer size (1 KB per port).
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