Sena User Manual

Figure 4-14 Filter application

4.2.9. Serial Port Parameters

To connect the serial device to the Super Series serial port, the serial port parameters of the Super

Series should match exactly to that of the serial device attached. The serial port parameters are required to match this serial communication. The parameters required for the serial communication are: UART type, baud rate, data bits, parity, stop bits, flow control DTR/DSR behavior and intercharacter timeout.

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UART type

First of all, the Super Series and the serial device must agree on the serial communication type, which is one of RS232, RS422, RS485 echo mode or RS485 non-echo mode. The Super Series serial port is configured for RS232 communication as a factory default, but it can also be configured for RS422 and

RS485 communication. To change the serial communication type, set up the mode in the Type menu.

The Super Series supports two types of RS485 communication – echo mode and non-echo mode, which are both two-wire mode. In RS485 echo mode, all data received from the serial port are automatically sent back to the serial port while there is no action of sending-back in non-echo mode.

For more information about pin out of serial port and wiring diagram, please refer to Appendix 1.

Connections section.

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Baud rate

The valid baud rate for the Super Series is as follows:

75, 150, 200, 300, 600, 1200, 2400, 4800, 9600, 19200, 38400, 57600, 115200 and 230400

The factory default setting is 9600.

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Data bits

Data bits can be between 7 bits and 8 bits. The factory default setting is 8 bits.

Figure 4-15 UART configuration

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Parity

Parity can be none, even or odd. The factory default setting is none.

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Stop bits

Stop bits can be between 1 bit and 2 bits. The factory default setting is 1 bit.

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Flow control

The factory default setting of the flow control is None. Software Flow Control using XON/XOFF and hardware flow control using RTS/CTS are supported by the Super Series.

Software flow control method controls data communication flow by sending special characters

XON/XOFF(0x11/0x13) between two connected devices. And hardware flow control method controls data communication flow by sending signals back and forth between two connected devices.

Note: Flow control is supported only in RS232 mode. RS422 and RS485 mode do not support any kind of flow control method in hardware or software.

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DTR/DSR behavior

The purpose of the DTR/DSR pin is to emulate modem signal control or to control TCP connection state by using serial port signal. The DTR is a write-only output signal, whereas the DSR is a read-only input signal in the Super Series side.

The DTR output behavior can be set to one of three types: always high, always low or high when open.

If the DTR behavior is set to high when open, the state of the DTR pin will be maintained high if the

TCP connection is established.

The DSR input behavior can be set to one of two types: none or allow TCP connection only by high. If user sets the DSR input behavior as Allow TCP connection only by HIGH, TCP connection to remote host from Super Series is made only when the DSR status is changed from low to high. And TCP connection to remote host is disconnected when the DSR status is changed from high to low. And also

Super Series accepts TCP connection from the remote host only when the DSR status is high. In case of UDP mode, Super Series receives UDP data from the remote host only when the DSR status is high.

In modem emulation mode, the connection to the remote host will be disconnected regardless of the current DSR input behavior option if the DSR status goes to low.

Note: DTR/DSR behavior menu will not be shown when the modem is enabled.

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Inter-character timeout

This parameter defines the interval that the Super Series fetches the overall serial data from its internal buffer. If there is incoming data through the serial port, the Super Series stores data into the internal buffer. The Super Series transfers data stored in the buffer via TCP/IP, only if the internal buffer is full or if the inter-character time interval reaches to the time specified as inter-character

timeout. If inter-character timeout is set as 0, then data stored in the internal buffer will be transferred immediately without any delay.

Optimal inter-character timeout would be different according to your application but at least it must be larger than one character interval within 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 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 have to set inter-character timeout to be larger than 8.3 ms. The inter-character

timeout is specified in milliseconds.

If users want to send the series of characters into a packet, serial device attached to the Super Series should send characters without time delay larger than inter-character timeout between characters and the total length of data must be smaller than or equal to the Super Series internal buffer size. The serial communication buffer size of Super Series is 256 bytes.

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