Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

How to implement modbus protocol using uart

Status
Not open for further replies.

SivaHari

Newbie level 3
Joined
May 9, 2016
Messages
4
Helped
0
Reputation
0
Reaction score
0
Trophy points
1
Activity points
44
Hi,
I want to manipulate the data using Modbus protocol over UART and i decided to use PIC24 series microcontroller to implement this process. I studied little bit about MODBUS protocol, but in that their using MTCP gateway as a intermediator. but still i did't get that how to implement this protocol over UART.
There also two interfaces
1. RS232/485
2. Ethernet (TCP/IP)

Two transmission modes
1. ASCII mode
2. RTU mode

I planned to use via RS232. but i can't to decide which Transmission mode is convenient. please kindly some one give idea about this process.
 

RTU is commonly used. For the implementation details, study the documents available at Modbus.org
There are also various code examples on the internet.
 
Hi,

There also two interfaces
1. RS232/485
2. Ethernet (TCP/IP)

I'd say three:
1. RS232
2. RS485
3. Ethernet (TCP/IP)

Klaus
 

There also two interfaces
1. RS232/485
2. Ethernet (TCP/IP)
In terms of MODBUS specification, they are different transport protocols, not only interfaces
1. MODBUS over serial
2. MODBUS over TCP
 

Anyway, I do not recomend to use 232.
485 much more relable.
Basicaly, we can use any phisical layer for MODBUS. But I think, CAN fit better. It has many h/w realized things like confirmation and CRC checking.
No reason to use such old interfaces in out century.
 

No reason to use such old interfaces in out century.
Objection! Apparently there are many reasons to use it today. You'll find that most HMI devices support as a standard protocol, multi-protocol converters like the HMS Anybus devices have MODBUS as a common protocol, etc., etc.

RS232 layer isn't suitable for actual bus (multi-drop) topologies, in so far MODBUS over serial mostly uses RS485.
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top