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I am Korean. I have shortage of English language ability. I seek understanding.

I download the protocol specification and implementation guide for Modbus over Serial line.

http://www.modbus.org/specs.php

I want concrete example file about serial communication.

Have you tried http://www.modbus.org? There's some really good information there, and lots of it.

Concrete is a combination of gravel, sand, and portland cement. Cement has been in use since the Romans.

Modbus is a serial protocol that was probably used by the Romans as well.
In closing: Modbus is a WELL published protocol!!

I have posted the next message some months ago about the usage of the XXMIT block in Concept. I don't know which programming language you are using. If you tell me, and a mail address also, maybe I can send you some example file.

I have been using this function in a lot of different cases and places, and I think I can help you. It's enough to use the XXMIT function to read data, but you have to set correctly all the parameters:

Command: 2100H for RS485 or 100H for RS232
Message lendth: Usually 5
Port: The number of the Port you are using
Baudrate: 9600, 19200, etc
Databits: Usually 8
Stopbits: Usually 1
Parity: Usually 2
Response tout: 1000
Retry Lmt:3
Startdly:100
Enddly:600

For message out you need an array [1..12] where you only use the 5 first elements, and they are:

Message[1]: Operation code :3 read registers
Message[2]: Number of registers that you read
Message[3]: Modbus address of the slave that you read
Message[4]: Address where you read (slave)
Message[5]: Address where you place the data (master)

Concrete: 1.a Existing in a material form; real b specific, definite (concrete evidence; a concrete proposal). I don't believe this discussion is very usefull for the man that is asking for help. We are not so very good in English, even though most of the people who write in this forum are not English speakers.

Hi,

I am currently working on project where I have to establish communication with several devices using Modbus protocol through RS232/RS485. I am new to Modbus though. I would really appreciate it if you could send me some of your code samples.

My email address is joni_sianturi @ hotmail. com

Thx a lot!!

There is a very helpful webpage about how Modbus works, including "concrete" example communications, at http://www.simplymodbus.ca/FAQ.htm