How to interface RS-485 / Modbus protocol

[PAP]

I 'd like to interface the Recorder (Screen Master2000:ABB) with a host computer. The recorder use RS-485 and modbus protocol for interfacing. Can anyone suggest me ,how to interface (Hardware and software)?. Is it require to use adaptor from RS-232(serial port at host computer) to RS-485? and the software which developed for RS-232, can it be used for this applicatiion?
Thanks for your kind
PAP

 

[ramvinod]

Use rs232-rs485 converter.
Write programe to communicate with the device.
Read data from the device.
if required i can send small programme to read data from the device.
After reading data you have to decode.
The address details of the device is required. c b ramesh
Director
Interface Electronics pvt ltd
19 nana street
t nagar
chennai
India
email:ife@vsnl.com

 

[aMiGo]

Software part:
if converter supports full duplex mode
you can write you program as usual RS232
communications, else you have to control
RTS/CTS signals.

For testing purposes I use COM PORT TOOLKIT
software available at

http://golikov.newmail.ru/eng/index.html

 

[jlada]

Pap;
Seems to me that the easiest part of your problem is the hardware interface - writing a Modbus protocol driver from scratch will be a tedious business. I've done this for the Omron Host Link and Allen-Bradley DF1 protocols and i recommend finding a pre-written (and debugged) library if at all possible. If you are determined to write the code yourself, this site has the description:

http://www.modicon.com/techpubs/toc7.html

Good luck...

 

[fernandoelec]

you can find that information in the following address:

http://www.modbus.org

I hope that this thing can help you.Let me to know if this is right.

Fernando Sánchez