Using the Modbus Plus Ports

Modbus Plus Features for Momentum

Introduction

Cluster Mode

64 Nodes

When a Modbus Plus network is constructed entirely of Momentum components, it may take advantage of two new features:

λcluster mode, which allows small groups of devices to be linked by short lengths of cable;

λsupporting up to 64 nodes on a single section of cable.

A cluster may consist of up to eight Momentum devices. A network may contain up to eight clusters.

The cable between devices in a cluster may be 10 in to 3 ft. The cable between clusters or between a cluster and the trunk must be at least 10 ft.

The maximum length of the network continues to be 1500 ft. The maximum number of devices in a network continues to be 64.

Note: Only Momentum devices are allowed in a cluster.

When a Modbus Plus network consists entirely of Momentum devices, then a single section of cable may support 64 nodes instead of the standard 32 nodes.

Example: If a single SA85 is added to a network of Momentum modules, the network is no longer Momentum only, but a mixture of devices. Each cable section must be limited to 32 nodes. Cable sections must be connected by a repeater.

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Schneider Electric Processor Adapter manual Modbus Plus Features for Momentum, Introduction Cluster Mode Nodes