Documentation for GPIB instrument programming /VIs for HP66xxa

[Johannes Eble]

Hello,

I have adopted a LabView application using a HP66xxA Power Supply. The
person who started the project is not available anymore. He has just
used the 'hp66xxA getting started" VI (inside the hp66xxA.llb) to set
the current limit and the voltage inside a control loop. But this is
too slow since the Power Supply get's initialized every iteration. I
would like to modify the application such that the Power Supply is
initialized only once. Inside the control loop I just want to set the
voltage. Unfortunately I can't find a documentation on how to program
the Power Supply with LabView (via GPIB). There are other VIs inside
the hp66xxA.llb which I could probably use, but I should get an
overview of the VIs. I
miss something like the description of the
DAQ-VIs. Is there anything available?

Any help would be great


Best regards

Johannes

[Dennis_Knutson]

Hopefully, I'm looking at the same llb that you're using. There's a lot of drivers for various 66xx power supplies. The HP66xxa.llb has a VI called HP66xxS VI Tree. If you open this and go to the diagram, you'll see all of VIs. If you turn on Context Help, as you move your mouse over the VIs, the help window will display the VI description. This is typically all the documentation you'll ever see on an instrument driver. You should also open the Getting Started VI and see what functions it calls. There really isn't all that much. Basically one VI to configure voltage and current and a trigger VI to turn on the output if Trigger Mode is selected. If you want finer control of the instrument, you might want to look at some of the other drivers available 0 662x,
664x, etc. I believe that they break down the instruments evern further so if you just want to change a voltage, you don't have to resend current settings, overvoltage protection, etc. You can also try the IVI driver. IVI drivers have some nice features like state caching, a simulation mode, and a great degree of interchangability. You would install the IVI driver for the specific instrument and then use the IVI class driver in your app. Then, if you ever swap out the instrument with another that also has an IVI driver, your application would not need to be changed.

[Johannes Eble]

Hello Dennis,

thanks very much for your answer.

On Fri, 14 Feb 2003 13:24:42 -0600 (CST), Dennis Knutson
wrote:

>Hopefully, I'm looking at the same llb that you're using.

Yes, it is the same lib 🙂


>There's a
>lot of drivers for various 66xx power supplies.

It is a HP6654A in my case.

....
>There really isn't all that much. Basically
>one VI to configure voltage and current and a trigger VI to turn on
>the output if Trigger Mode is selected.

So, first I have to call Initialize.vi. My program just has to set the
voltage so the only vi I have to use is the configure.vi in immediate
mode. So I don't have to use the Trigger.vi after the Initialize.vi,
right?

In the end I have to call close.vi. I have realized that sooner or
later I get an error if I don't call Close.vi before I stop the
program. Then I have to close the program and load it again.
Can I configure LabView to call the Close.vi automatically in the end?

>If you want finer control of
>the instrument, you might want to look at some of the other drivers
>available 0 662x, 664x, etc.

I didn't find a special driver for the HP6654A.


The problem is that I have to drive a longer way to my customer to use
the hardware (also the HP6654A). Therefore, my program is able to
simulate the hardware. The last time I have visited him I realized
some problems with the HP6654A (GPIB/VISA) communication. I can't use
read the values for voltage and current with the Read Meas.vi because
I always get a VISA timeout. The customer doesn't have an original NI
GPIB card in his computer. The GPIB card is not recognized by LabView
(the driver is crossed out in the NI DAQ tool), but it is recognized
by the computer and it is working (they have checked it with a program
running in the dos console). Also, I can set the voltage and the
current of the Power Supply from LabView. I just can't read the
values.
So , they said that it dosn't matter if the GPIB driver is crossed
out, but I am not sure if I can use the card.


Best regards

Johannes