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Data from Serial

Do I need a DAQ board to read data off a serial port?

I have Labview 5.0, 16550 UART (COM 1) and I'm getting data off a RS-232
Port. The data is weak (in the 10s of microvolts).

Thanks.

-Dorian

dorian@jps.net


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> Do I need a DAQ board to read data off a serial port?
>
> I have Labview 5.0, 16550 UART (COM 1) and I'm getting data off a RS-232
> Port. The data is weak (in the 10s of microvolts).
>

In general, no, you just use the serial functions in
either VISA or the serial port to read the logical
value of the serial port. The bit collecting, parity,
and handshaking business are taken care of by the
HW and serial driver.

With values this low, they will all be below the
threshold voltage and no data will arrive. If the
signal is a logical serial signal that is this weak
because of distance or poor cabling, then it would
be best to fix the cabling or whatever. Amplifying
the signal would just amplify whatever noise exists,
and the signal would be a mess.

To answer the o
riginal question, though -- yes, a
DAQ board can measure this if the board can apply
a gain or if you preamplify it.

Greg McKaskle
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Hi Greg,

Thanks for the 411. I figured out the problem (the cables).

*peace*

-DG

In article <37FF3D26.A4035DF8@austin.rr.com>,
GMCKASKLE@austin.rr.com wrote:
> > Do I need a DAQ board to read data off a serial port?
> >
> > I have Labview 5.0, 16550 UART (COM 1) and I'm getting data off a
RS-232
> > Port. The data is weak (in the 10s of microvolts).
> >
>
> In general, no, you just use the serial functions in
> either VISA or the serial port to read the logical
> value of the serial port. The bit collecting, parity,
> and handshaking business are taken care of by the
> HW and serial driver.
>
> With values this low, they will all be below the
> threshold voltage and no data will arrive. If the
> signal is a logical serial signal that is th
is weak
> because of distance or poor cabling, then it would
> be best to fix the cabling or whatever. Amplifying
> the signal would just amplify whatever noise exists,
> and the signal would be a mess.
>
> To answer the original question, though -- yes, a
> DAQ board can measure this if the board can apply
> a gain or if you preamplify it.
>
> Greg McKaskle
>


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