Advantech EKI-1500-CE Series, User Manual

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37 EKI-1500-CE Series User Manual
The EKI-1500-CE Series provides Multi-access function through an Ethernet connec-
tion path, allowing a maximum of five connections to open one serial port simultane-
ously. In this mode all connections must use the same serial setting. If one serial
setting within this configuration is configured differently, the data communication will
not function correctly.
Figure 4.2 Configuring Virtual COM Mode
The Host Idle Timeout setting monitors the connection between the host and the
device. If the Host Idle Timeout setting time is reached, the device server will release
the resources allocated to the port mapping. This prevents a stalled host from affect-
ing the connective device.
The Multi-access function has two modes. One is Normal mode and the other is
Round-Robin mode .
4.2.1 Normal mode
By disabling the Response Timeout parameter, the EKI-1500-CE Series will operate
in normal mode. When multiple hosts simultaneously open the serial port, only the
first connected host obtain management control, the remaining connections only
have data communication function. Each serial port supports up to five simultaneous
connections, so multiple hosts can transmit/receive data to/from the same serial port
simultaneously. Every host can transmit data to the same serial port, and the EKI-
1500-CE Series will also transmit data to every hosts. When the multiple hosts trans-
mit 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-CE Series receives data
from serial port, the data will also be transmitted to the connected hosts simultane-
ously.
4.2.2 Round-Robin mode
By enabling the Response Timeout parameter, the EKI-1500-CE Series Series
operates in “Round-Robin mode”. Each serial port supports up to five simultaneous
connections allowing hosts to simultaneously transmit/receive data to/from the same
serial port. Every host can simultaneously transmit data to the same serial port, EKI-
1500-CE Series processes the data in the order arrived. The EKI-1500-CE Series
processes the first host’s request and replies. The serial device server determines
the end of the serial acknowledgement through a response timeout. When EKI-1500-
CE Series serial device server does not receive a response from the serial port after
a response timeout query, the device replies with an acknowledgement and then pro-
cesses the next host request. With an increased number of hosts, response time may
be lengthy, increasing the period of the Response Timeout.
Frame Break is an important parameter for Round Robin mode. The parameter is a
smart method of reducing ineffective waiting periods and streamlining the transmis-
sion process.