Moxa Technologies NE-4100 - Manual (Page 28)

NE-4100 Series User’s Manual Choosing the Proper Operation Mode
4-2
Overview
NE-4100 Series Embedded Network Enablers act as a bridge to connect your serial devices to the
Ethernet. The built-in TCP/IP stack saves you a lot of time on programming networking protocols.
One simple step allows you to choose the proper operating mode, and then use your computer to
access, manage, and configure your serial device over the Internet from anywhere in the world.
Traditional SCADA and data collection systems rely on serial ports (RS-232/422/485) to collect
data from various kinds of instruments. Since NE-4100 Series Network Enablers are equipped
with the ability to convert between serial and Ethernet signals, your SCADA and data collection
system will be able to access all devices connected to a standard TCP/IP network, regardless of
whether the devices are used locally or at a remote site.
Three different socket modes—TCP Server, TCP Client, and UDP Server/Client—and one real
COM mode are available. The main difference between the TCP and UDP protocols is that TCP
guarantees delivery of data by requiring the recipient to send an acknowledgement to the sender.
UDP does not require this type of verification, making it possible to offer speedier delivery. UDP
also allows multicasting of data to groups of IP addresses.
NOTE Pictures in this Chapter use NE-4110S as an example.
TCP Server Mode
In TCP Server mode, NE-4100 provides a unique
IP:Port address on a TCP/IP network. NE-4100 Series
boards wait passively to be contacted by the host
computer, allowing the host computer to establish a
connection with and get data from the serial device. This
operation mode also supports up to 4 simultaneous
connections, so that multiple hosts can collect data from
the same serial device—at the same time.
As illustrated in the figure, data transmission proceeds
as follows:
1. The host connects to the NE-4100 Series boards
configured for TCP Server Mode.
2. Once the connection is established, data can be
transmitted in both directions—from the host to the
NE-4100 Series boards, and from the NE-4100
Series boards to the host.