本手册介绍Modicon光纤中继器(部件号490NRP253、490NRP254、490NRP954、NWFR85D200和NWFR89D200)的安装和操作方法。
中继器具有以下特点:
型号490NRP253在两个Modbus Plus连接之间提供光纤点对点链接。中继器包含一个光纤收发器和一个Modbus Plus电接口。
型号490NRP254和NWFR85D200提供Modbus Plus节点或网段之间的光纤总线和电气线降链路。每个中继器包含两个光纤收发器和一个电Modbus Plus接口。
型号490NRP954和NWFR89D200提供远程I/O节点或网段之间的光纤总线和电气线降链路。每个中继器包含两个光纤收发器和一个电子远程I/O接口。

除工作功率和安装方式外，Modbus Plus中继器型号490NRP254和NWFR85D200相同，远程I/O型号490NRP954和NWFR89D200相同。

Modbus Plus网络的电气连接是通过标准的Modbus Plus 9针“D”连接器。连接到远程I/O网络是通过一个“F”式连接器和外部Modicon远程I/O 14db抽头。中继器的电端口与其他Modbus Plus或Remote I/O设备具有相同的网络连接、规格和限制，必须相应地对待。请参考Modbus Plus系统规划和安装指南(GM-MBPL-001)或984远程I/O规划指南(GM-0984-RIO)，了解有关规划网络配置和网络电缆安装的信息。

This manual describes how to install and operate Modicon Fiber Optic Repeaters (Part Numbers 490NRP253, 490NRP254, 490NRP954, NWFR85D200, and NWFR89D200).
The repeaters have the following characteristics:
Model 490NRP253 provides a Fiber Optic Point-to-Point link between two Modbus Plus connections. The Repeater contains one Fiber Optic Transceiver and one electrical interface for Modbus Plus.
Models 490NRP254 and NWFR85D200 provide Fiber Optic Bus and electrical Line-Drop links between Modbus Plus nodes or network segments. Each Repeater contains two Fiber Optic Transceivers and one electrical Modbus Plus interface.
Models 490NRP954 and NWFR89D200 provide Fiber Optic Bus and electrical Line-Drop links between Remote I/O nodes or network segments. Each Repeater contains two Fiber Optic Transceivers and one electrical Remote I/O interface.

Except for their operating power and mounting methods, Modbus Plus repeater models 490NRP254 and NWFR85D200 are identical, and Remote I/O models 490NRP954 and NWFR89D200 are identical.

Electrical connection to the Modbus Plus network is through the standard Modbus Plus 9–pin “D” connector. Connection to the Remote I/O network is through an “F”–style connector and external Modicon Remote I/O 14 db tap. The electrical port of the Repeater has the same network connections, specifications and restrictions as other Modbus Plus or Remote I/O devices, and must be treated accordingly. Refer to the Modbus Plus System Planning and Installation Guide (GM–MBPL–001), or the 984 Remote I/O Planning Guide (GM–0984–RIO) for information regarding planning your network configuration and the installation of the network electrical cable.