Network Configuration
 
Overview
This section contains guidelines for configuring a Modbus Plus network for distributed I/O servicing.
Limit Types of Devices on Network
To ensure deterministic timing, the network should consist of just one programmable controller node and the required group of I/O nodes.
Non-I/O devices, such as additional controllers, programmers, or operator interfaces, should communicate with the I/O network controller through a separate Modbus Plus network or other type of connection.
Maximum Configuration
The table below summarizes the Modbus Plus network's maximum configuration for a distributed I/O application consisting of Momentum products.
Parameter
Specification
max. number of nodes
64 including Controller
max. distance between two nodes
450 m (1500ft)
min. distance between two nodes
3 m (10ft)
max. length of network
450 m (1500ft)
max. number of data words (16-bit words)
500 input, 500 output
max. number of I/O points (16 bits/word)
8000 input, 8000 output