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recive information via RS 485

Created by: Consiliere at: 6/18/2009 12:25 PM (6 Replies)

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6/18/2009 12:25 PM	Rate (0)
Consiliere Posts: 14 Rating: (0)	Hello, I need a help. I must recive information via RS 485 from other device. What is procedure to configure port? Thx in advance
Consiliere Posts: 14 Rating: (0)
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6/18/2009 1:28 PM	Rate (0)
dchartier Grandmaster-Expert Joined: 9/27/2006 Last visit: 12/4/2023 Posts: 12188 Rating: (2637)	Hello Consiliere; First thing is to determine what protocol is to be used over RS-485. RS-485 (and other RS-xxx standards) is a physical layer description. For example, Modbus-RTU can use RS-485 connections, and the S7-200 can be a Modbus slave or even a Master, with a bit of work. If it is an ASCII protocol, like some barcode readers I have worked with before, exchanging caracters, then you will need to develop a subroutine in the PLC to decode the information transfered. Same would apply to any other proprietary protocol used by different manufacturers. So you need to find out exactly how the 3rd-party unit is using as exchange protocol. Then we may be able to provide more help. Hope this helps, Daniel Chartier

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6/18/2009 1:43 PM	Rate (0)
AMAZINGAHMED Gold Member Joined: 8/27/2006 Last visit: 10/29/2023 Posts: 718 Rating: (87)	I think you should look at the S7-200 Tips&Tricks. http://support.automation.siemens.com/WW/view/en/1232912
	Last edited by: AMAZINGAHMED at: 6/18/2009 1:44 PM The more you know, The more you know that you don't know
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6/18/2009 1:58 PM	Rate (0)
Paresh Posts: 116 Rating: (1)	Hi, One thing about RS-485 will be hardware specification. There are two ways of communication in RS-485. One is half duplex (2 wire) and another is full duplex (4 wire). You need consided this for wiring diagram for third party device. Another things will be serial communicaiton settings such as baud rate, parity etc. If you can provide more details on deivce you are going to use for RS-485 communiation, we can help you in more detailed way. Thanks and Regards Paresh
Paresh Posts: 116 Rating: (1)
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6/18/2009 6:59 PM	Rate (0)
Darius Platinum Member Joined: 9/28/2005 Last visit: 11/6/2023 Posts: 2957 Rating: (242)	Paresh One thing about RS-485 will be hardware specification. There are two ways of communication in RS-485. One is half duplex (2 wire) and another is full duplex (4 wire). You need consided this for wiring diagram for third party device. S7-22x isn't 4 wire device. Is it ?
	Best regards, Darius
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6/19/2009 5:46 AM	Rate (0)
Paresh Posts: 116 Rating: (1)	Hi Darius, Yes you are right... S7 200 has two wire 485 interface only. I was talking about general 485 interface. Regards Paresh
Paresh Posts: 116 Rating: (1)
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6/23/2009 8:48 AM	Rate (0)
Consiliere Posts: 14 Rating: (0)	Hello guys, thank you for your help i have a more information.. In protocol there is no parity, 8 data bits per character, baud rate 19200.. also the message starts with "CE" and finishes with "00" I am trying but with no success
Consiliere Posts: 14 Rating: (0)
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