HP4194A driver for LabWindows/CVI

[wmf]

Howdy,
I want to write a program to communicate with HP 4194A impedance analyzer. I searched the driver library and found the related drivers for LabView 6.0/7.0/8.0.  Are they  also usable for  LabWindows/CVI 7.0? I am new in this communication work, could you give me some suggestion on how to build communication between software and devices (such as tutorial or examples)? Any input is appreciated!
Regards,
wmf

[Al M]

wmf,

On the driver download page for the HP 4194A there is one written for LabWindows/CVI 6.0.  You can find that driver here:

http://sine.ni.com/apps/we/niid_web_display.download_page?p_id_guid=E3B19B3E9397659CE034080020E74861

This should work fine in CVI 7.0.  Cheers.

Al M.

Applications Engineer

National Instruments

[wmf]

Got it,
Thanks a lot!

[MJF]

Just for future reference, sometimes it is easier to just do the instrument I/O directly than it is to use a driver. Sometimes a driver is serious over kill if all you need to use is a couple of functions. In cases like that, I simply use VISA I/O and write my own short functions to get what I need.

I've also found over the years that drivers should be taken with a huge grain of salt. They don't always work as advertised and can be quite frustrating when they are broken.

[wmf]

I was able to use NI-488.2 communicator to control the analyzer and complete the operation. How can I read the Gain-Phase data set shown on the screen? According to the program code, "A=" is register for display data A(Gain), "B=" is register for display data B(Phase). I tried to read but always had I/O timeout error. I took a screenshot and put it in the attachment. Could you give some suggestion? Thanks!

[MJF]

Unfortunately, I can't really tell you how to do that. You will need to consult the programming manual for the instrument.

[Al M]

wmf,

 

I don't have the instrument available so it will be hard to trouble shoot.  What about trying to send A=?  or maybe a lower case a.  Cheers.

Al M.

Applications Engineer

National Instruments

[MJF]

I know this is probably an obvious question but it can't hurt to ask...

When you were trying this using the communicator panel, did you try to query or did you try to read?

You need to enter the command string in the field and then press the query button, not do a read. Or you can write the command and then read. but the query button does that in one operation for you.

[wmf]

MJF, AI M

Thanks a lot for your quick response!

The command is "A?". I used NI Spy to monitor the measurement procedure. After I sent trigger command "SWTRG", I saw a loop invoked automatically. It's composed by ibwrt(ud,"rqs2",4) and ibrsp(ud,3). In the end, different response value triggered ibwrt(ud,"rqs0",4). The snapshot is attached.

According to the manual,  "RQS(0): Mask the status byte(RQS0 means all masked)". Could you tell me what the purpose of this loop is? (I guess it tells the communicator when the analyzer is ready to do I/O but not sure) How can I incorporate it into the C source code in LabWindow/CVI?

wmf

[Al M]

wmf,

You may find the following links helpful, they help explain the RQS command:

http://digital.ni.com/public.nsf/websearch/577D62CFCEE1EC7886256F1F00813215?OpenDocument

http://digital.ni.com/public.nsf/websearch/D6ADFE8D993E53F186256848005D7A6B?OpenDocument

Also, you may find the GPIB 488.2 reference manual of some use.  Here it is:

http://www.ni.com/pdf/manuals/321819e.pdf

Al M.

Applications Engineering

National Instruments