Visa questions

[m]

From the examples I am reasonably sure that I can communicate with the
serial port via visa but I don't know what is really going on.

Where do the ASRL???::INSTR strings contained in the visa resource list box
come from ? (??? = 1, 3, or 10 on my system.)

What do these strings mean and how do they relate to the ports? I only have
2 COM ports but the box has 3 entries.

Where is the visa documentation?

Thanks

Mark

[Ben]

Hi Mark,


>Where do the ASRL???::INSTR strings contained in the >visa resource list box
>come from ? (??? = 1, 3, or 10 on my system.)
The ??? comes from your systems configuration, i.e. com1, com3,etc. I would guess the 10 is your parallel port (just guessing).



>What do these strings mean and how do they relate to >the ports? I only have
>2 COM ports but the box has 3 entries.
I believe these names are defined by VISA standards. If you are using a current version of MAX you can define aliases for your ports if you want.

Ben

[m]

Thanks Ben,

Using your pointer to MAX, I was able to figure out that the VISA docs and
utilities are installed in a separate root directory rather than under the
National Instruments directory.

Mark

"Ben" wrote in message
news:506500000005000000226F0000-1017707437000@exchange.ni.com...
> Hi Mark,
>
>
> >Where do the ASRL???::INSTR strings contained in the >visa resource
> list box
> >come from ? (??? = 1, 3, or 10 on my system.)
> The ??? comes from your systems configuration, i.e. com1, com3,etc. I
> would guess the 10 is your parallel port (just guessing).
>
>
>
> >What do these strings mean and how do they relate to >the ports? I
> only have
> >2 COM ports but the box has 3 entries.
> I believe these names are defined by VISA standards. If yo
u are using
> a current version of MAX you can define aliases for your ports if you
> want.
>
> Ben

[Randy Schmidt]

The definition indicates the serial port 1 or 3 as well as the parallel port
"10". The advantage of VISA is that I could just change the initialization
string to "GPIB0::INSTR" and the code that you have written will work
without any changes since VISA will convert the viWrite and viRead commands
properly for you for serial comm or using the GPIB and other protocols as
they are implemented.

I recommend VISA over the serial driver or GPIB driver to give you
flexibility in the future.

Later.

Randy

"m" wrote in message news:TK3u8.27624$CH1.25054@sccrnsc02...
> From the examples I am reasonably sure that I can communicate with the
> serial port via visa but I don't know what is really going on.
>
> Where do the ASRL???::INSTR strings contained in the
visa resource list
box
> come from ? (??? = 1, 3, or 10 on my system.)
>
> What do these strings mean and how do they relate to the ports? I only
have
> 2 COM ports but the box has 3 entries.
>
> Where is the visa documentation?
>
> Thanks
>
> Mark
>
>