I/O error with COM port

[sy 715]

I have a RS485 line going into COM5 of my PC. Using HyperTerminal, I can talk to my serial device. However, there are problems with LabVIEW VISA functions. I can open the connection. I/O errors were given when I try to read or write. Is this because LabVIEW does not support RS485? What can cause the I/O error? Thanks.

[Lab Viewer]

2 questions:
- how did you do com5/RS485 connection?
- what's happening if you try to use MAX instead of HyperTerminal?

[sy 715]

Good question. In fact, I think the problem stems from how COM5 is mapped to my PC. As for the second question, I got the same I/O error when using MAX. I believe that there is a conflict between NI software and the software I use to map the RS485 line to COM5.

I am using Advantech's ADAM 4570 module to convert a RS485 line to ethernet. The ethernet cable goes into the PC. A software utility is used to map the ethernet connection to COM5. It is conflict between this utility and NI. Any idea on how to resolve the conflict? Thank you.

[abrause]

Some tips,

First off, computer com ports are only RS-232. Make sure you are using the RS-232 port on the
ADAM-4570. Do you have to configure this port as RS-232 with Advantech software? If the ADAM is
configured as RS-485, you won't be able to talk to it without an RS-232 to RS-485 converter. Stick
with RS-232.

Secondly, make sure you have shut down all other software that is using COM5. Only one application
can use the port at a time and sometimes other applications don't release the port properly.

If HyperTerminal can talk to the ADAM, then everything is configured properly for a LabVIEW app. Be
sure to put a carriage return at the end of the command to the ADAM. HyperTerm does this
automatically, LabVIEW doesn't. Start with the basi
c commands you used with HyperTerminal.




"sy" wrote in message news:50650000000500000037530000-1007855737000@exchange.ni.com...
> Good question. In fact, I think the problem stems from how COM5 is
> mapped to my PC. As for the second question, I got the same I/O error
> when using MAX. I believe that there is a conflict between NI
> software and the software I use to map the RS485 line to COM5.
>
> I am using Advantech's ADAM 4570 module to convert a RS485 line to
> ethernet. The ethernet cable goes into the PC. A software utility is
> used to map the ethernet connection to COM5. It is conflict between
> this utility and NI. Any idea on how to resolve the conflict? Thank
> you.

[Lab Viewer]

I think that Alan already give you a starting point.
Let us know if you still have problems.

p.s.: My suggestion is a rs232/485 converter too.

[sy 715]

Thank you.

[Rainer Ehrt]

sy wrote:

> Good question. In fact, I think the problem stems from how COM5 is
> mapped to my PC. As for the second question, I got the same I/O error
> when using MAX. I believe that there is a conflict between NI
> software and the software I use to map the RS485 line to COM5.
>
> I am using Advantech's ADAM 4570 module to convert a RS485 line to
> ethernet. The ethernet cable goes into the PC. A software utility is
> used to map the ethernet connection to COM5. It is conflict between
> this utility and NI. Any idea on how to resolve the conflict? Thank
> you.

#########

Hi Sy,
I use Advantech's and Adlink's RS-485 Modules since quite a while and
intend to use the ADAM 4570 (2 port eth) in future as well. So I familiar
handling RS-48
5 with usual RS-232 / RS-485 converters.
Have you handled with usual converters, to test if your serial
communication VIs work at all? Maybe this is a better way to get started.
Adlinks RS-232/485 converter (ND6520) costs just about 100$ and works well
at my place.
Have you told LabVIEW that you have more than 2 com port in your computer?
There is some kind of configuration file, I don't know the name of, where
this has to be entried.

Ciao,
Rainer

[ofir]

I have the ADAM-4571L and EDG-4504 for ethrnrt to Rs 485 or rs 232
they dont work properly and retern error massege when I try to get or send data
is there a problem whit the VISA and advantech config program

[EdbO]

I have also here an ADAM-module 4571. With the ADAM-program and Hyperterminal it will return data, but in Labview I get errors. Using an RS232 to RS485-converter in combination with the ADAM 4571 is IMHO overkill, so I replaced the 4571 with the 4520. I had great experience with this module.

[Zimin]

Hello,

I have got the same problem with VISA functions here and none of the advice here solves it. I use Advantech COMport mapping utility to create a virtual COM3 port. My LabView VI looks similar to the Basic Serial Read and Write VI, which is in examples. At first I used ADAM 4571 alone (as a convertor rs485/tcpip) with data acqusition modules (ADAMs 4017,4080,4050,4024-all rs485). The Labview scheme didn't work (error mesage is written below). So I put ADAM 4520 (rs232/rs485) between my ADAM 4571(rs232/tcpip) and modules for data acquisition. The VISA functions still generate the error message:

Error -1073807298 occurred at VISA Write in Basic Serial Write and Read.vi

Possible reason(s):

VISA:  (Hex 0xBFFF003E) Could not perform operation because of I/O error.

In Advantech ADAM 4000-5000 utility works everything ok. Does anybody know a solution to this problem.

Thank you very much.