Momentum Sales & Marketing Modbus Plus 170 PNT Series - Manual (Page 27)

Modbus Plus for DIO Servicing
870 USE 103 00 May 2001 27
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