Data Mode (Usdg Mode) - Advantech EKI-1521 User Manual

There are two operating mode of Multi-access function. One is Normal mode;
another is Round-Robin mode.
Normal mode
Disabling "Response Timeout" parameter, the EKI-1500 series will operate in "normal
mode". When multiple hosts open the serial port simultaneously, the EKI-1500 series
only offers control ability for the first connected host and provides data communica-
tion function for others. Each serial port supports up to five simultaneous connec-
tions, so multiple hosts can transmit/receive data to/from the same serial port
simultaneously. Every host can transmit data to the same serial port, an
1500 series will also transmit data to every hosts. When the multiple hosts transmit
data to the same serial port at the same time, the received data from Ethernet and
the outputs of serial port are mixed. When the EKI-1500 series receives data from
serial port, the data will also be transmitted to the connected hosts simultaneously.
Round-Robin mode:
Enabling "Response Timeout" parameter, the EKI-1500 series will operate in "Round-
Robin mode". Each serial port supports up to five simultaneous connections, so mul-
tiple hosts can transmit/receive data to/from the same serial port simultaneously.
Every host can transmit data to the same serial port simultaneously, but the EKI-1500
series will process the data communication in order. The EKI-1500 series will process
the first host's request and reply the response to the first host. The EKI-1500 serial
device server can determine the end of the serial acknowledgement via response
timeout. When EKI-1500 serial device server receives nothing from serial port after
the setting of response timeout, the device will reply the acknowledgement to the
host and then process the next host's request. While the connected hosts are more
and "Response Timeout" is long, the process time is much longer.
Frame Break is a very import parameter for Round Robin mode. This parameter is
the smart way to reduce inefficient waiting time and the EKI-1500 series can transmit
data more efficiently. Disabling the Frame Break function, the EKI-1500 series will
wait "Response Timeout" period, whether the device have transmitted the data. Dur-
ing this period, the commands from hosts will be queued and the EKI-1500 series just
processes this command. Enabling "Frame Break", if the serial port idle is longer
than the "Frame Break" period, the EKI-1500 series will assume the communication
is completed and continue the next host's query. This is an efficient way to reduce the
waiting time and improve the performance.
3.5.2

Data Mode (USDG Mode)

The EKI-1500 series can be Data server or Data client either. Both operations sup-
port TCP and UDP protocol. The EKI-1500 series makes your serial devices behave
just like networking devices. You can issue commands or transmit data from serial
devices, which connected to the EKI-1500 series, to any devices that are connected
to the Internet.
The EKI-1500 series allows most 5 host PCs accessing data simultaneously via poll-
ing networking architecture. You can use it according to your application. If you want
to access the EKI-1500 series, you must ascertain your application software supports
standard networking application programming interface (API) such as: WinSock
Socket.
33 EKI-1521/1522/1524 User Manual
EKI-
d the