What are the *.mnu files that download with the Hewlett Packer instrument drivers?

[djpritchard]

I have a  rather odd problem.  I ran a program on another machine and all works fine, but ported it to a vendor site and have only one issue that I can't seem to resolve.  I'm talking to several HP6632A DC Power Supplies, an HP 34401A and an HP8720C.  Everything is smooth until the HP6xxxA Read Output Voltage Current.vi is called.  It shows 0 volts and 0 amps, on the Front Panel of this VI, even though there is a voltage and current value.  The supplies are setting up fine, but for some reason this VI pulls back zeroes - and I've tried it on both of the supplies in the stand.  There are no errors showing on the supply.

Now there is one difference, short of the obvious difference of the physical supplies.  The vendor site has a USB to GPIB NI adapter.  At the development site, a NI GPIB card was installed.  Again, I'm puzzled due to the lack of any error.

Thanks in advance!

[Dennis_Knutson]

First, what does the subject have to do with your question?

Second, what kind of error handling do you have in your program? Just reading errors from the supply is not enough. Have you been able to read the values when you execute the command in MAX?

[djpritchard]

I should have done a better job tying it all together, but I was thinking that maybe the *.mnu files have something to do with the issue.

Second - bear with me, I'm a real novice at LabVIEW.  What is MAX?  I'm assuming it's something that might allow me to fire off individual commands.

The VOUT$ and IOUT$ commands are being sent to the instrument, but for some reason the values are coming back zero.

[Dennis_Knutson]

The mnu files are how the palette menus are defined and have nothing at all to do with a VI working or not.

MAX is short for Measurement & Automation Explorer and it is what you use to configure a GPIB interface and it also has options to communicate to an instrument. After you have right clicked on the controller and MAX and selected Scan for Instruments, you can then right click on an instrument and select to communicate with it. 

The commands are not VOUT$ or IOUT$. They are VOUT? and IOUT?.

[djpritchard]

Dennis - thanks.  I fired up MAX and I do get the values back when I do either an IOUT? or VOUT$.  Now I'm using Agilent (HP) drivers downloaded from NI, but again, I'm not setting the value.

I've attached the VI

[djpritchard]

Dennis - disregard that last VI I attached.  This is the correct one.

Thanks

[Dennis_Knutson]

Probe the output of the VISA Reads and also look at the user data setting. That determines how the result us parsed.

[djpritchard]

Dennis - again, keeping in mind I'm just coming up to speed, what do you mean regarding the "user data setting"?  I'm thinking that you're referring to the data type that is in the main VI - is that correct?  Also, when you recommend to probe the VISA reads, is that a matter of setting up a numeric output, or using some capability withing VI to probe ?

Dennis - thanks for your time in building my working knowledge of LabVIEW!  I'm coming up the curve!

Message Edited by djpritchard on 04-13-2010 11:51 PM

[Dennis_Knutson]

The user data is the output of the UserData property node. This is clearly shown on the block diagram.

A probe is one of the basic debug tools in LabVIEW. Right click on a wire, select "Probe' and you will get a window that shows the value contained in the wire.

Since you seem to lack basic LabVIEW knowledge, you really need to start with the free tutorials.