Moxa Technologies NPort 5400 Series - Manual (Page 23)

NPort 5400 Series User’s Manual Choosing the Proper Operation Mode
4-2
Overview
NPort device servers enable network operation of traditional RS-232/422/485 devices, in which a
device server is a tiny computer equipped with a CPU, real-time OS, and TCP/IP protocols that
can bi-directionally translate data between the serial and Ethernet formats. Your computer can
access, manage, and configure remote facilities and equipment 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 NPort serial device servers enable network operation
of instruments equipped with an RS-232/422/485 communication port, your SCADA and data
collection system will be able to access all instruments connected to a standard TCP/IP network,
regardless of whether the devices are used locally or at a remote site.
The NPort is an external IP-based network device that allows you to expand the number of serial
ports for a host computer on demand. As long as your host computer supports the TCP/IP protocol,
you won’t be limited by the host computer’s bus limitation (such as ISA or PCI), or lack of drivers
for various operating systems.
In addition to providing socket access, the NPort also comes with a Real COM/TTY driver that
transmits all serial signals intact. This means that your existing COM/TTY-based software can be
preserved, without needing to invest in additional software.
Three different Socket Modes are available: TCP Server, TCP Client, and UDP Server/Client. 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.
ATTENTION
Pictures in this Chapter will use the NPort 5400 as an example.
Real COM Mode
The NPort comes equipped with COM drivers that
work with Windows 95/98/ME/NT/2000/XP
systems, and also TTY drivers for Linux systems.
The driver establishes a transparent connection
between host and serial device by mapping the
IP:Port of the NPort’s serial port to a local
COM/TTY port on the host computer. 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.