Eurotech ZyWAN, User Manual

Page: 102 / 130

ZyWAN - User Manual
102 110150-1001F
FIELD/OPTION EXPLANATION
Duplex Select the duplex mode for the Terminal Server. This selects a
mode of operation for handling bi-directional communication with
a serial device.
Full Duplex : This mode is designed for unsolicited data from
serial devices, full bi-directional communication, or any serial
protocol which may send large or multiple responses to a
request. In this mode, the Terminal Server is always able to
receive data on both the serial and network ports, as long as a
client is connected to the IP Port .
Half Duplex : This mode is designed for simple request-response
networks, especially where serial port sharing with another
Terminal Server may be required. After a request is received
from the network and sent to the serial port, one response is
expected (with a number of bytes less than the Buffer Size ).
After data is transmitted to the serial port and the Response
Timer times out with no data or after one response is received
and returned to the network client, the Terminal Server does not
read any more serial data until the next request.
Modbus Mode
Select the mode of operation, if Modbus protocol translation is
required. Modbus protocol translation is only needed if the
network client is sending “Open Modbus/IP” protocol requests.
Translation is not needed for other types of data or if the
standard serial Modbus (ASCII or RTU) is encapsulated within
the TCP/IP requests. Options available are:
None : This is the normal option for most applications.
Open Modbus to ASCII : Converts Open Modbus/IP protocol
requests to serial Modbus ASCII protocol, and converts the
ASCII response to an Open Modbus/IP response.
Open Modbus to RTU : Converts Open Modbus/IP protocol
requests to serial Modbus RTU (Binary) protocol, and converts
the RTU response to an Open Modbus/IP response.
Serial Driver Select whether to use the Native Linux (ttyS) serial driver or the
ACSCOMM driver. The ACSCOMM allows for half-duplex RS-
485 communication and can provide somewhat better handling
of hardware flow control if required.
Broadcast Only Select Yes to only send to the serial port. This option allows the
network computer to send data to the serial port without waiting
for a response. The Response Timeout and Duplex mode are
ignored.
Demark IP Packets If a large network packet is sent to the ZyWAN and gets broken
up over the network, the fragments can sometimes arrive at
slightly different times. Each packet is sent to the serial port, but
if the time difference is too great, the serial device may not react
properly. Set this value to Yes to allow delayed IP packets to be
put together before sending to the serial port. The value for
Demark Timer is used to specify the time to wait for additional IP
data. Set this value to
No
if this feature is not needed.
Echo Cancel RS-485 This option is used when the internal (COM3) or an external RS-
485 converter is used in half-duplex mode. Set this option to
Yes to block the reception of echo bytes on the serial port which
get echoed back from the RS-485 device.