no appearance usb-gpib in measurement & automatisation

[Dr. Gonzo]

There're 2 devices by Rohde&Schwarz connected by GPIB. I've created a measurement process by LabVIEW and it works. No i have to involve an other older device in the automatic measurement.

When i starting the "Getting Stated Wizard" for verifying my hardware and software installation the troubleshhotin wizard is succesful completed.

GPIB-name: GPIB0

Interface Type:  GPIB-USB-HS

Status: passed

Now, when I want to communicate with my instrument´, there appears no instrument under "Devices and Interfaces" in the Measurement & Automation Explorer. All instrumenst are powerde and connnected.  To talk with instruments by a LabVIEW-Vi is possible but there's nothing in the M&A-explorer. So i can't neither scan for instruments nor communicate with them.

Ex ante thanx 4 your help.

[Andre_Saller]

When you scan for Instruments in MAX, the command "*IDN?" will be sent to every GPIB-Adress. When a device answers, it will be added to the list. If the device does not answer(For example because it does not understand this command) it will not be added to the list. You can communicate with the device anyway, by using a development environment.

As you said your device is old, so it is pretty propable, that it does not "understand" the command "*IDN?".

[f.grasdepot@laposte.net]

Hi,

you can test immediately the presence of your device with output/enter
style commands on the url: www.labtab.com/ni_GPIB0
You have to put the GPIB address of your device to 1 (dip switches )
and output a command it recognizes ( find that dusty manual ... if old
enough, no chance to get a response to "*idn?" ;=) ) when it answers,
you know that it is time to make it in LabVIEW ... starting from
something that works ...

Changing the dip switches is also a good way to know that there is no
conflict of GPIB addresses , the test must also be done with only one
device on the GPIB bus ...

Regards,

FG







Dr. Gonzo wrote:
> There're 2 devices by Rohde&Schwarz connected by GPIB. I've created a measurement process by LabVIEW and it works. No i have to involve an other older device in the automatic measurement.
> When i starting the "Getting Stated Wizard" for verifying my hardware and software installation the troubleshhotin wizard is succesful completed.
> GPIB-name: GPIB0
> Interface Type:  GPIB-USB-HS
> Status: passed
> Now, when I want to communicate with my instrument´, there appears no instrument under "Devices and Interfaces" in the Measurement & Automation Explorer. All instrumenst are powerde and connnected.  To talk with instruments by a LabVIEW-Vi is possible but there's nothing in the M&A-explorer. So i can't neither scan for instruments nor communicate with them.
> Ex ante thanx 4 your help.

[Dennis_Knutson]

Not quite correct. After an instrument is detected, then the IDN? command is sent. If it repsonds, then the result is displayed by MAX and if it doesn't respond because the instrument doesn't support it, the listing will display something like "instrument failed to respond to id query" but it will still be listed. If scan for instruments fails to faind anything, then verify that the instrument is actually set for remote communication. With some, you have to do this from a front panel command. You might also want to try a different cable.

And G. ,

I for one am getting a little tired of your never ending push to sell your product here. I fail to see how it could possibly help in any of the recent postings you've made. You might want to review the Terms of Use policy at the bottom of the screen.

Message Edited by Dennis Knutson on 06-01-2006 08:01 AM

[f.grasdepot@laposte.net]

Hi,

"Dennis Knutson wrote:
> Not quite correct. After an instrument is detected, then the IDN? command is sent. If it responds, then the result is displayed by MAX and if it doesn't respond because the instrument doesn't support it, the listing will display something like "instrument failed to respond to id query" but it will still be listed. If scan for instruments fails to faind anything, then verify that the instrument is actually set for remote communication. With some, you have to do this from a front panel command. You might also want to try a different cable."

Not correct at all, I saw many instruments, especially old ones or home
made that were not listed in MAX.
I do not get the way how an instrument, not responding to "*idn?" ,
might be listed since it does not respond ! That the GPIB address might
be listed as not responding is possible and obvious but that the
instrument is present has a flare of mystery since no low-level
commands of the GPIB bus norm enables to identify a device ...

That's the interest of having a web page, where you can send directly
GPIB commands ( even low-level commands as get, mta unl etc ...) , wait
and get the response over the GPIB bus without installing anything ...


"> I for one am getting a little tired of your never ending push to
sell your product here. I fail to see how it could possibly help in any
of the recent postings you've made. You might want to review the Terms
of Use policy at the bottom of the screen."

To be tired, please cite alternatives ... because the page I recommend
is free and helps to debug when using a GPIB device for the first time
with a fine degree of low-level tuning of the GPIB bus ... with only a
browser ... I am sure it is quite clear how it may possibly help ...
Concerning the terms of Policy, this is a public forum so ????

To be constructive, If there is a web page developped with LabVIEW on
the same model, I would be glad to know about it (and help/contribute)
and I would also be glad to know about any user-friendly alternative to
do the same ...
Otherwise I, indeed, have and will have a good reason to suggest to use
"my page" to debug any GPIB tricky situation ...

This is especially true for trainees and beginners, since having a
direct dialog tool enables to separate two problems:
- be sure that the instrument responds to commands of its manual
without programming
- make a LabVIEW program to implement these commands

Regards,

FG

[GPIB_Guru]

>> That the GPIB address might be listed as not responding is possible and obvious but that the instrument is present has a flare of
>> mystery since no low-level commands of the GPIB bus norm enables to identify a device ...

If you send the listen address of a device and then take away the ATN line, the device will be in the LACS state. Being in the LACS state will cause the device to transition from AIDS to ANRS in the acceptor state machine. When in the ANRS state, it will assert NDAC. The controller can detect the NDAC assertion to verify the presence of a device on the GPIB. It cannot ascertain the identity of the device (hence the *IDN? query), but it can ascertain that a device exists at a given primary address. In IEEE 488.2 sense, this is the FINDLSTN protocol and it works for all IEEE 488 devices, not just IEEE 488.2 devices since the requirement of NDAC is in the IEEE 488.1 standard.

Oh, one more thing. If you add a new device and the entire bus stops working (I am not sure if that is what is happening in the original post or if just the new one is failing), than you could be having an address conflict with the controller such that everytime the controllers tells itself to talk, both your device and the controller are talking, which causes problems. You may want to change the GPIB address of the new device and see if that fixes the problem.

Message Edited by GPIB Guru on 06-02-2006 07:26 AM

[f.grasdepot@laposte.net]

Hi dennis,

"> I for one am getting a little tired of your never ending push to
sell your product here. I fail to see how it could possibly help in any
of the recent postings you've made. You might want to review the Terms
of Use policy at the bottom of the screen.Message Edited by Dennis
Knutson on 06-01-2006 08:01 AM"

I was unable to get your e-mail to answer you, so, this is to mention
that to take into account some of your remark, no link able to direct
NI users to other websites is present in the direct gpib tool page at:
www.ieee-488.com/ni_gpib0. A walk on this page is so only directed to
use freely GPIB without any software installation, on an NI GPIB
controller and from a web page, which may be no small feat when stuck
in GPIB bus ...
I will so recommend this page in my Posts from now on ( when useful
obviously )

Any other observation is welcome,

Regards,

FG

[Dennis_Knutson]

The Guru has given a great explanation of what goes on before MAX issues the *IDN? to find all listeners and why any properly configured GPIB instrument will be listed whether or not it actually responds to the *IDN?. Anyone can turn on GPIB-Spy and watch this.

I fail to see the utility of your web based GPIB communiction utility since every user already has not one, but three utilities already installed on their local computer. One is the communicator launched when you right click on an instrument in MAX and select 'Communicate with Instrument;. The second is started from Tools>NI-488.2>Interactive Control. The third is started from Tools>NI-VISA>VISA Interactive Control. Your tool, as far as I can tell, does nothing that these other tools don't already provide. If your program does, please explain.

The Terms of Use in part says:

"Your Conduct. In the areas on the Site where users transmit or post Communications, you are prohibited from:

• Uploading files that contain software or other material protected by intellectual property laws (or by rights of privacy or publicity) unless you own or control the rights thereto or have received all necessary consents.
• Uploading files that contain viruses, corrupted files, or any other similar software or programs that may damage the operation of another's computer.
• Advertising or offering to sell or buy any goods or services. "

It's the last item that I was referring to. Your "free" version is limited to a single instrument at address 1. You charge 1200 Euros/USD for software that might actually be useful. I see the majority of your posts as advertisements of this commercial product since they are very often, way off topic and offer no help to the person who posted the question.

[GPIB_Guru]

I don't see how that website or your API really helps people. You still need to have your driver installed since it is making NI-488.2 calls using scripting. NI-488.2 includes an interactive control to help you out and provide you low-level control of the bus. If you have VISA installed, which most people do since they want to use instrument drivers (sorry, but instrument drivers use VISA - introducing your own version of a VISA-like API will not help) , they have the VISA interactive control, which is very user-friendly and easy to do.

Just my $0.02.

[f.grasdepot@laposte.net]

Hi Dennis,

You did not post the reference to the Guru explanation, it interests me
and other users ... so

The fact that GPIB direct dialog tools exists from NI does not prevent
another one to be useful ... For instance mine at
www.ieee-488.com/ni_gpib0 gives an ActiveX/COM interface to GPIB-32.dll
, can use the low-level GPIB bus commands , can be saved and programmed
and has a microsecond clock ( among others ... ). That may be useful
and I find it convenient. Only the users can tell and your opinion
imports as such ... Web access to GPIB from a web page on a site is so
user-friendly that I used no other thing now for debugging a GPIB
problem.

The "terms of use" of Google groups DO NOT SAY that is inappropriate
conduct : > - Advertising or offering to sell or buy any goods or
services. " Please verify.
And if it were advertising to cite a product name, it would qualify as
inappropriate to cite LabVIEW or NI, which does not seem reasonable.

As you mentioned without my asking for, I am the author of a software
that is sold 1200 euros/USD and that works with NI GPIB controllers. To
avoid giving a wrong impression of my software, I shall add that it
works also for many other GPIB controller brands and that the price is
for unlimited copy, which you did not mention. It seems also that it
may qualified me to advise people on the GPIB bus and I did not notice
"off topic" and "of no help" qualification of my posts from people to
which I answered.

However, to clarify my intention, I inform you that, any commercial
reference is removed from the gpib direct dialog tool in the page
www.ieee-488.com/ni_gpib0.
You can verify. People using it will so be able to see if it is of some
help.
For me I shall refer to it freely since I find it useful for my
answers. As an example, I used it to answer to the HP33120A recent post
instead of starting to program.

As I respect you as a proven veteran of this forum and I shall pay
attention to refrain my enthusiasm to my product. I know you will help
me to do this ...

As a GPIB author, I am more concerned by the good use of GPIB so I hope
we can go back now to finding solutions to GPIB problems of users which
is the subject we are all interested in.

Thank you for your remarks,

FG

P.S: I am still interested in knowing about the magic of Guru and if it
is possible to detect a device only with GPIB commands ...