Interface though other than GPIB

[STRASS]

I downloaded a driver that only interfaces with GPIB, but my PC is not equiped with a GPIB. The measuring instrument also has LAN, USB, and RS232 ports. Is there any way to interface with one of these so as not to have to purchase an GPIB adapter?

[Emilie S.]

Hi STRASS:

I'm assuming that you downloaded an instrument specific driver from our Instrument Driver Network. If so, and it was for GPIB communication, then you will not be able to use this driver for anything other than a GPIB connection. What instrument are you trying to interface with? Have you searched for serial drivers for this instrument? Are you using LabVIEW? Even if you cannot find serial instrument drivers for your instrument you can still write basic VISA code for communication. Within LabVIEW you can go to Help->Find Examples and find a couple serial example programs that could get you going.

Regards,

Emilie S.
Applications Engineer
National Instruments

[STRASS]

Hey,
I am trying to interface with an Agilent 54852A Oscilloscope. I could not find any other drivers for this particular product. I am using labview. If I use VISA to interface through the serial, would I have to write an entire new driver? Thanks for your help.

Message Edited by STRASS on 06-17-2005 01:58 PM

[JLS]

Hello,

You can certainly use VISA to communicate with your device via a serial port. You will not have to write an entire driver; I imagine you will simply want to write some commands to have the instrument perform some specific tasks. The "commands" will be nothing more than strings, which using the VISA Write function in LabVIEW, you'll be able to write to your instrument. Now, some commands you send to it may request data; in such cases you will simply use a VISA Read function to read that data! Now, there are a couple considerations:

1. There are some serial configuration parameters, such as baud rate, data bits, stop bits, and parity, which you will want to make sure to match up on both sides of your communication. The easiest way to do that is to find out the defaults for your instrument (your instrument's user manual should have that) and then use the VISA Configure Serial Port VI to match your instrument on your PC side. Speaking of the manual, you'll be using that quite a bit to check the exact form of the strings you'll be using to write to your instrument; this should be very well documented in a user manual.

I would suggest using the attached program to start; it will write *idn? to your instrument and read the response. *idn? is a very common command for an instrument to reply to with a description of itself. Note that there is a linefeed character appended to it; this is usually called a termination character and is a common way to indicate the end of a serial transmission. The code in the block diagram also shows that termination is enabled, as the instrument very likely uses termination characters when it replies. I have used the termination character hex 10 which is a linefeed character, but other common ones include hex 13, which is a carriage return.

Ok, I hope this helps! You may also want to try contacting the manufacturer as they may have a driver already written, but it won't be difficult to simply write the commands directly with VISA calls. Of course, the more functionality you access on the instrument, the more commands you'll have to look up in the manual.

Repost if you continue to have trouble!

Best Regards,

JLS

PS - the vi attached is for version 7.1