GPIB and ancient HP signal generator

[RFMike06]

Hi all,

     I'm trying to automate a really old HP 8672A signal generator

[Dennis_Knutson]

Do you have a question to go along with your multiple posts?

[RFMike06]

Sorry about the duplicates with no questions....is there a delete post function anywhere?  oh well...

Here's my original question:  I'm trying to automate an HP 8672A signal generator with my GPIB-USB-B interface and Visual Basic 6.  I've succesfully used most other VB NI-488 functions to automate slightly newer devices, so I should have everything in place.  All I can get it to do is, when I open NI's Measurement and Automation Explorer and scan for instruments, the generator switches to remote operation.  Then when I close the NI MAX software it switches back to local, and my VB functions don't do anything.

So my question is can I even use these functions and/or interface to communicate with this thing?  You can set the 'HP-IB address' by taking the top cover off and turning two dials, which count in octal.  Then there is a chart that specifies what 'Talk' and 'Listen' address corresponds to the selected 'HP-IB' address.  What is going on here?  Any experience or insight would be great.

Thanks  

[Dennis_Knutson]

Switching to remote in MAX would be expected and the scan for instruments is likely to return a message that the *IDN? failed. To old of an instrument to support that command. I really don't know why it would switch back to local when you exit MAX but you should be able to communicate with it. In MAX, the 'ib' commands are used and they will work with old instruments. You may have to experiment though, with the command termination. Instruments that comply with 488.2 only require the EOI be asserted. Older instruments used a variety. Some required a CR + EOI, LF +EOI, CR+LF, CR + LF + EOI, etc. If you have a manual, you might be able to find this information there. Find a simple query in the programming manual and test the different possibilities.

[RFMike06]

Thanks for the reply.  I just wanted to note that with the slightly newer HP models (but still circa 1980) I do get the *IDN? Failed message in MAX, but have been able to automate those without any problems.  But with these particular models the scan doesn't find an instrument at all, no GPIB address. 

Also, I've tried using different termination settings in the MAX properties menu.  Is that the same as using the different termination methods you mentioned?  How would I implement those termination methods in my VB code?

Lastly, I do have a manual, but it's kind of confusing when it comes to terminology.  I've attached a GPIB connector description from the manual as well as a table of messages and commands it's supposed to accept, and a description of data string syntax.  How does this tie into the NI VB commands?

Thanks again

[RFMike06]

OK, I was finally able to figure it out using the Interactive Control command prompt in MAX.  No special termination methods were needed, it looks like I just had to use ildev with the correct GPIB address (always 19 on these models).  The device still doesn't show up in a scan for instruments, I guess it's just too old to return any sort of response at all.  But it works with ibwrt now, and that's all I needed.  Thanks. 

[Mark333]

Good morning,

I have the same instrument for my home lab!! It was used as part of a Network Analyzer in the past at Tektronix in the IC Lab. That HP generator was designed by a EE who worked for NASA!!! 

I would like to program it using Python!!!

Mark Logue

Portland, Oregon

mark3eern@yahoo.com