VISA vs Serial Functions

[Slade Squire]

I'm writing a program, which is highly dependant on serial communication...

As a beginner, I was wondering if you could tell me which form of subVI I
should use,
the VISA sets, or the Serial sets.

Which is optimized better? (I would tend to think the Serial Sets)
Which is easier to use/debug?
Which would you suggest?

--
Slade Squire
Programmer
Rectifier Technologies Pacific
Melbourne, Australia

[Gorka Larrea]

This is a very discussed topic, some like serial and some VISA. All depends on what you want. Some say VISA is not well documented, and that you must install NI-VISA if you want it to work, what is no good if you have a small executable to install in a computer and have to install it (12MB?). I allways thought VISA was better because it's easier to understand, and the data flow implementation looks good. When i made some GPIB drivers using VISA i was completely impressed for the easyness to program, but when i tried to do the same with serial... no way! I didn't get it to work and used serial vi's.
All things are good until they fail.
Good luck

[Rob Cole]

Unfortunately the VISA drivers fail if you have a computer with an HP GPIB card installed. The HP VISA does not talk to LabVIEW as successfully and even the serial ports become non-existent to the VISA system. I have solved all of those problems by using the serial port drivers. And the serial port drivers do make for smaller executables.

[Tims]

Hi Rob,

I have had good success implementing HPIB cards and NI-VISA V2.5 with LV6
using this technique.

Uninstall HP-VISA and reinstall just the HP SICL libraries. Make the
driver auto-find the devices but then remove the serial devices it has
found.

Install NI-VISA V2.5.

In MAX you will see the serial and parallel ports but not the GPIB
devices. This doesn't mean that they are not there. You can still see them
with 'find resources' function and the pull down VISA selection controls.
You can still even use aliases created in MAX.

Tim

Rob Cole wrote:

> Unfortunately the VISA drivers fail if you have a computer with an HP
> GPIB card installed. The HP VISA does not talk to LabVIEW as
> successfully and even the serial ports become non-
existent to the VISA
> system. I have solved all of those problems by using the serial port
> drivers. And the serial port drivers do make for smaller executables.

[D D]

The serial drivers are easier to use. That's not to say that the VISA vi's
are difficult. The example vi's provided by NI show how to provide required
inputs. There are situations where the serial vi's are inadequate, such as
timing out communication to a device using hardware flow control. This,
afaik, is impossible with the serial vi's but well supported by the VISA
vi's.

In practice, I have used resisted using the VISA vi's until recently when
the serial vi's were inadequate. I will probably try using VISA for all new
I/O vi's.

"Slade Squire" wrote in message
news:9i3162$o1t$1@perki.connect.com.au...
> I'm writing a program, which is highly dependant on serial
communication...
>
> As a beginner, I was wondering if you could tell me which form
of subVI I
> should use,
> the VISA sets, or the Serial sets.
>
> Which is optimized better? (I would tend to think the Serial Sets)
> Which is easier to use/debug?
> Which would you suggest?
>
> --
> Slade Squire
> Programmer
> Rectifier Technologies Pacific
> Melbourne, Australia
>
>