Installation guide

Introducing the Modbus Plus Network

890 USE 100 00

1.1 1 Expanding the Network

1.1 1.1 Linear Expansion

The simplest network configuration consists of two or more nodes

connected to a single section. Figure 15 shows four nodes connected in

a basic dual-cable configuration.

PROGRAMMABLE

CONTROLLER

PROGRAMMABLE

CONTROLLER

PROGRAMMABLE

CONTROLLER

NODE

NETWORK

ADAPTER

NODE

UP TO 32 NODES MAX., 1500 ft (450 M) CABLE MAX.

10 ft (3 M) CABLE MIN.

500 ft (150 M) CABLE MAX. DIFFERENCE, CABLE A TO B

MEASURED BETWEEN ANY PAIR OF NODES

CABLE A

CABLE B

Figure 15 Basic Configuration Example

The basic configuration in Figure 15 will satisfy the network

requirements if all of the following specifications are met:

V Not more than 32 nodes are connected to the network cable

V The total endtoend length of each network cable is 1500 ft

(450 m) or less

V The difference in length between cables A and B is 500 ft (150 m)

or less, between any pair of nodes

V The length of each cable segment (between a pair of nodes) is 10 ft

(3 m) or more

V The proper type of impedance termination is used at each node site

(tap’s internal jumpers removed at inline sites, and installed at end

sites).