Installation guide

Introducing the Modbus Plus Network

890 USE 100 00

1.2 Network Terminology

The following terms are used in this guide to describe network

elements:

Network The grouping of nodes on a common signal path that is accessed by

the passing of a token. It consists of one or more cable sections. For

example, all of the nodes in Figure 2 are on a network .

NODE

REPEATER

NODE

NODE NODE

SECTION

CABLE

SEGMENT

DEVICES

ARE ON

TWO SECTIONS

ONE NETWORK

Figure 2 Standard Network Terminology

Section A series of nodes that are joined only by cable segments. The section’ s

signal path does not pass through any kind of node device. Sections

are all part of one network, sharing the same token and address

sequence. In Figure 2, the Repeater joins two sections. Each section

can be up to 1500 ft (450 m) long, and can contain up to 32 physical

node connections.

Cable Segment A single length of trunk cable between two taps. Taps are passive

devices that provide connections for the trunk cable segments.

In Figure 2, the cable connection between the nodes at addresses 10

and 5 is through one cable segment . Another cable segment connects

nodes 5 and 64.

On dual-cable networks, two cable segments run in parallel between

pairs of nodes.