Introduction to Modbus
Modbus protocol is a master-slave communications Industrial architecture (RTU), created to be implemented Modicon PLCs.
Why use this protocol and consider that it is better than other industrial protocols, implementation is easy and simple network configuration dropping down is defined (RTU) by way compact binary data concerning the device connection with a PC supervisory computer with a remote unit (RTU) RTU Modbus variations exist which apply and ASCII version which I consider less efficient in handling and size of records.
There are a lot of implementations of this protocol in the variety of languages Java, Python, C programming, etc.
It seems that a lot of the Industrial controllers, OPC, HMI and Scada handle serial Modbus RTU this protocol either RS485 or RS232 physical layer RS422.
In some cases the industry is required to monitor the status of certain variables that are records of an industrial controller (PLC) if this controller is integrated modbus supervisor will have access to a Mini adsequible and easy web Scada using ESP8266 and Arduino IDE.
Directly talking about our application has been implemented in the ESP8266 module Modbus RTU protocol as a slave, it has taken our previous project designing a Web Scada
SVG based on our tank example, has an integrated web and Communication Modbus slave RTU Scada, the idea is to apply in the future in an application Indsutrial Real.
1 – The ESP8266 module makes the connection to our local wireless network, and the assigned IP address TCP publish our SCADA design based on SVG.
2 – The connection between the serial port TTL ESP8266 with our PC (Modbus Master Simulator) used the FTDI converter (- USB serial TTL) is performed.
3 – Previously should check the communication parameters of our slave modbus in the code in Arduino IDE parameters such as:
regBank.setId (1); Slave address
slave.setBaud (19200); Transmission speed
regBank.get (40001); To request records in this test Holding Register 0 or 40000 or 40001 (depending on the device track moves).
Video Test simulator Modbus Master
Tank level ranges from 0 to 100 made reading Holding Register 40001 Modbus Master.
1 1 ESP8266
2 1 Converter FTDI Serial USB
3 1 Regulator de 5 a 3.3v for supply ESP8266