Meridian 2300M Series, Руководство пользователя

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11/11/2006 3 Rev 2.0
1.0 INTRODUCTION
The Meridian Technologies’ series PX-2300 Multidrop Fiber Optic Data Modems are designed to accept
RS-232, RS-422, and 2 & 4-wire RS-485 signals and optically transmit them in simple string and ring
networks as well as in dual, counter-rotating, self-healing rings with dual masters for increased fault
protection and redundancy. Up to 99 modems can be connected in a single network to provide almost
unlimited connectivity. Applications include traffic signal control, industrial process controls, and SCADA
networks.
The PX-2300M is the stand-alone or surface mount model while the PX-2300R is the rack mount unit that
occupies two slots in a standard Meridian chassis.
The Meridian PX-2300 series modems are equipped with built-in self-diagnostics that monitor and report
the status of each of the modems on the network and the fiber itself. This feature is unique to the PX-
2300 modems and provides a significant advantage over competitive products. On the PX-2300M
(surface mount modem) local access to the diagnostic information is via a large, easy to read, LCD
display on the top of each modem.
The PX-2300 is also compatible with Meridian’s SpectraSmart
™
PC Diagnostic network management
system. SpectraSmart continuously monitors “real-time“ data for Meridian equipment to determine the
integrity and operational status of diagnostic-equipped fiber optic modems, optical interfaces, fiber, etc.
(See section 6.2 for more details on SpectraSmart). Remote access to SpectraSmart diagnostics is
available via an RS-232 interface to a computer. Access to the diagnostic information on the PX-2300R
is available via the USB or RS-232 interface to Meridian’s SpectraSmart software that resides on a
standard computer.
The modems regenerate fiber optic signals and provide greater system loss budgets (and increased
distance). Wide temperature operating range and isolated diagnostic RS-485 driver allow to use
modems in harsh environments where ground loops and EMI/RFI interference may occur
2.0 NETWORK CONFIGURATIONS
The PX-2300 modem is designed to connect central computers and controllers with multiple remote
workstation / terminal units through fiber optic cables. The Master modem receives asynchronous data
from the central computer or controller and transmits it over fiber optic cables to Slave modems at
distances up to 30 miles (50 km) between the modems – using singlemode fiber. The PX-2300 modem
supports RS-232 data with handshake, RS-485 data (2-wire or 4-wire) or RS-422 full duplex data at
communication speeds up to 115 Kbps.
PX –2300 modems can be configured to operate in the following ways:
Multi-drop (Bus or String): Typical configuration for multi-modem applications including traffic
controllers, railways & subways, and oil or gas pipelines where linear arrays of data communication
nodes are required. Data from host (Master) is transmitted to all remote modems or slaves. The remote
equipment addressed at the remote location will accept the data, perform the necessary function and
transmit its data back to the master via the other remote modems between itself and the master.
Figure 2-1 below illustrates a typical string or bus configuration using one master and a number of
remote or slave modems at various add/drop locations. Because of the dual optical paths, it is not
necessary that the master be located at one end of the string or bus. Utilizing both clockwise and
counter-clockwise optical paths allows slave modems to be placed on either side of the master providing
added logistical flexibility.