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vrf Need help - Problems with writing & reading to/from serial port

Question asked by rachell on Jan 3, 2005
Hi Kevin,

Thank you very much. It works fine now with the Interface Event object.

Best Regards,

-----Original Message-----
From: Kevin Dowsey []
Sent: Tuesday, January 04, 2005 12:31 AM
To: Lederman Rachel
Subject: RE: [vrf] Need help - Problems with writing & reading to/from
serial port

You can use the I/O->Interface Event object to find out how many bytes
available for reading.

Depending on how the balance sends the information, will determine how
should use this object.   Sometimes it makes sense to put two one after
other, the first one gets the initial count of bytes and the second is
to make sure you know all the bytes often you would put a short delay
between the two.

Then if you have 13 bytes you do one type of read and if you have 11
you can do another type of read.

At 02:20 PM 3/01/2005 +0200, you wrote:
>Hi Kevin,
>Thank you, your advise about the I/O Bus monitor was of a great help.
>Now I can read the message, but the problem is that the balance usually

>sends 11 bytes, but once in a while it sends 13 bytes (2 for status)
>when the weight is not stable and than the reading gets wrong. How
>should I know how many bytes to read? Or should the manufacturer send a

>fixed number of bytes each time?
>Best Regards,
>-----Original Message-----
>From: Kevin Dowsey []
>Sent: Monday, January 03, 2005 12:04 AM
>To: Lederman Rachel
>Subject: Re: [vrf] Need help - Problems with writing & reading to/from
>serial port
>You might have a more fundamental problem with the configuration, like
>the EOL
>settings.   Does your balance require a return or Line Feed as an EOL
>character ?   This also needs to be set the right way.
>You should seperate the send a receive into seperate  objects for
>debugging purposes
>You can also use the I/O Bus monitor to debug this process and then you

>can see whether the Balance sends anything back at all.
> > Hello,
> >
> > I have a balance that is connected to COM2 and responses correctly
> > to a demo program of the company.
> >
> > I define a device on the COM2 - w1@2. The serial properties are :
> >
> > Baud Rate                9600
> > Character                 8
> > Stop Bits                 1
> > Parity                      None
> > Handshake              None
> > Receive Buffer Size  4096  (the default)
> >
> > I need to send the character "p" and in return get an answer like :
> > w1
> > 200.26 g
> >
> > It seems very simple, but all I get is an error message :
> >
> > I/O error or timeout occurred with serial interface at 2
> >
> > I am using VEE7 Pro and IO Libraries for Instrument Control Revision

> > M.01.01.
> >
> > Please help.
> >
> > Thank you,
> >
> > Rachel
> >
> >  <<sercom.vee>>


Kevin Dowsey
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