The cable to be used is a shielded twisted pair telephone type.
Modbus rtu cable type.
1 modbus ascii 2 modbus rtu based on serial communication like rs485 rs422 rs232 3 modbus tcp ip based on ethernet.
The wattnode bacnet and modbus meters communicate using rs 485 tia eia 485 a half duplex differential signaling at 9600 19200 38400 and 76 800 baud.
The 3 most common modbus type used today.
For example belden 3105a cable can be specified but different types of cable with equivalent characteristics can be used.
But any cable with similar characteristics can be used to connect all the devices together.
The protocol interconnects field equipment such as sensors.
Modbus is popular in industrial environments because it is openly published and royalty free.
Modbus is a data communications protocol originally published by modicon now schneider electric in 1979 for use with its programmable logic controllers plcs.
Modbus protocol is a messaging structure developed by modicon in 1979 used to establish client server communication between intelligent devices.
Modbus cable interface quickly and easily with most existing plant control architectures by using belden cabling for modbus.
Here describe a difference between modbus ascii vs modbus rtu vs modbus tcp ip below.
Modbus rtu is an open serial rs 232 or rs 485 protocol based on master slave or client server architecture.
The twin consists of two conductors that are twisted together.
In modbus protocol one master communication with many devices approx 240 device.
Type of cables to use.
Modbus has become a de facto standard communication protocol and is now a commonly available means of connecting industrial electronic devices.
Over short distances 100 ft.
With its open and simple specifications the modbus protocol is widely used to control device communications in industrial applications.
Go back to modbus rs485 cabling rules 5.
For modbus communications a shielded and twisted pair cable is used.
Modbus has been a standard for interfacing remote i o and plcs into the process dlc system for over 20 years allowing most legacy control systems to interface easily with modbus.
As indicated in the following table modbus modes and functions differ depending on cable type.
