Using the Modbus Plus Ports

Standard Cabling Schemes

Introduction

In a standard Modbus Plus cabling scheme, each peer device connects via a drop

 

cable to a tap along a trunk cable.

 

Length

 

 

The maximum length of cable from one end of the network to the other is 1500 ft.

 

(450 m) if no repeaters are used.

 

 

You can use up to three Modicon RR85 Repeaters to extend the cable to up to

 

6000 ft. (1800 m). Each repeater allows you to extend the cable 1500 ft. (450 m).

 

 

 

 

Description

Part Number

 

 

 

 

Modicon RR85 Repeater

NW-RR85-000

Distance

 

 

 

 

Nodes must be separated by at least 10 ft. of cable. This requirement is more than

Between Nodes

satisfied by standard drop cables:

 

 

 

 

 

Description

Part Number

 

Modbus Plus Drop Cable, 2.4 m / 8 ft.

990 NAD 211 10

 

Modbus Plus Drop Cable 6 m / 20 ft.

990 NAD 211 30

Number of

 

 

 

 

The maximum number of devices in a network is 64:

 

Devices

λ If you use only Momentum products, you may use up to 64 devices on one

 

 

cable section without a repeater.

 

 

λ If you use a mixture of devices, you may use up to 32 devices on one cable

 

section. You must use a repeater to connect to another cable section. You may

 

use up to three repeaters and four cable sections in all.

 

Termination

 

 

You must terminate both ends of the network. If your network consists of two or

 

more sections separated by a repeater, each section must be terminated at both

 

ends.

 

Continued on next page

870 USE 101 10 V.2

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Schneider Electric Processor Adapter manual Standard Cabling Schemes, Between Nodes