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Author Topic: RS-485 problem  (Read 15884 times)

Eddie

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RS-485 problem
« on: March 14, 2007, 03:37:16 AM »
Hello,
I'm a new user of PLC.
I have a problem about RS-485 communication between PLC and PC.
The PLC model is T100MD888+. I want to develop a program by using VB 2005.

The RS-485 has three modes, I tried to using TxRTS RxRTS mode.
In TLserver transmits data is successful, but it is fail of using the open source VB.net program.
http://www.tri-plc.com/appnotes/VBasicDotNetComm.htm

But it is also fail on TxRTS RxON, the result will not a direct command.
Is the problem on RTS?  

http://www.aten-usa.com/?product&cat=594&Item=IC485S&PHPSESSID=57455b500b87e720dc1571b777d06509
This is the model of RS-485 which is I'm using.
« Last Edit: March 14, 2007, 03:38:09 AM by Eddie »
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FQ-ONG

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Re:RS-485 problem
« Reply #1 on: March 14, 2007, 04:32:28 AM »
I'm not sure RS485, but communication fine between my VB 2005 program and PLC by using RS232.
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Eddie

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Re:RS-485 problem
« Reply #2 on: March 14, 2007, 04:36:22 AM »
I also tried RS-232, it is work fine and I want to know how to send RTS control signal on VB2005
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support

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Re:RS-485 problem
« Reply #3 on: March 14, 2007, 10:49:34 AM »
If you use Auto485 adapter and set in Auto mode then no need to control RTS. Most other makes of RS485 adapter requires control of the RTS pin.
« Last Edit: March 15, 2007, 05:09:47 PM by support »
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Eddie

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Re:RS-485 problem
« Reply #4 on: March 14, 2007, 10:52:11 AM »
Have any source code is control RTS pin in VB2005 or .NET version??
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support

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Re:RS-485 problem
« Reply #5 on: March 15, 2007, 05:09:19 PM »
 After examinging the code, found out that the VB6 sample program that you can download from our website actually uses the MScomm1.output command which is the built-in command of the Visual Basic Active X control and it does not affect the RTS.

Try using the Auto485 instead. It should work great!
« Last Edit: March 15, 2007, 05:10:22 PM by support »
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FQ-ONG

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Re:RS-485 problem
« Reply #6 on: April 04, 2007, 06:38:41 PM »
Have any source code in VB2005 version that can download from website instead of VB6 ???
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support

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Re:RS-485 problem
« Reply #7 on: April 06, 2007, 12:59:26 PM »
Did you try running the VB6 source code on VB2005? Any problem encountered? It is better to provide source code that run on more common platforms than the latest platforms, since each customer has a different development system from another and each will have different wishes.
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FQ-ONG

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Re:RS-485 problem
« Reply #8 on: April 09, 2007, 11:15:19 PM »
No, VB6 source code totally can't open on VB2005. I'm running the VB.NET source code on VB2005. You've right, it is better to provide source code that run on more common platforms than the latest platforms, since the VB2005 was not a common platform.
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