Potential feature with the HP68XX initialize vi

[Kaspar]

Hello,

   I have found a potential feature and/or desired improvement to the HP68XX init vi, I would like to see the GPIB timeout increased from its present value of 500 to possibbly 2000 (or more). Maybe even allow the user to select their own and have a default value of 2000. Initialliy the HP68XX init vi worked well during my initial testing with a GPIB timeout of 500, which was part of the HP68XX init vi. As soon as the amount of data that I was sending to the power suppy increased I started getting -1073807339 errors during a GPIB write operation. Usually this timeout error occurs during a VISA read operation on a serial port, so I was confused over why I was getting this error during a GPIB VIA write.

      So after pulling the hair out of my head for several hours a found a clue in this forum that told me what to do, increase the timeout error and life is better. So in order that someone else does not get hosed up like I did and assume that the HP68XX init vi is perfect can the next release of the init vi incorporate the updates I mentioned at the beginning of this message?

Regards,

Kaspar. 

[GovBob]

Kasper,

 Thanks for the heads up. I am going to try this on a different HP power supply Init vi I am having intermittent problems with. HP66xx. Could you provide the error code you received when it wasn't working. Thanks

[Dennis_Knutson]

Kaspar,

I'd be a bit hesitant to make the change to the Init function. I have only taken a brief look at all of the functions but the majoiryt of the writes are small and should finish in the default of 500 msec. Increasing the timeout for all will just increase the time it takes to report an error when something is really wrong. What is typically done in functions that can take quite a bit of time, is to read the current timeout value, set a new one, and before exiting, set the timeout to what it originally was.

GovBob,

In another thread, he says the error code is -1073807339.

Message Edited by Dennis Knutson on 06-30-2008 07:30 PM

[Kaspar]

Hello,

   The error code that I was getting is/was -1073807339.   I have observed the operation of the power supply with a scope to verify correct operation and I have not seen any issues. So please let me know if your errors have go away when you have increased the timeout.

Regards,

Kaspar

[Kaspar]

Hello,

    As a result what I have learned about communicating with the HP power supply I have applied it to the other instruments that I have working with, such as scopes. I have increased the time out for all of my GPIB devices to 20000, which initially seems to be a ridiculous number, but here is what I have observed so far in a small amount of testing that I have done, I am not getting com errors, but more importantly the instruments are functioning properly. 

   I have created my own init vis for all of my instruments to do the following actions in the following order.....

1. Clear the VISA resource
2. Close the VISA resource
3. Open the VISA resource
4. Clear the VISA resource
5. set the timeout to 20000 ( a ridiculous large number)

   Yes I am aware that the above sequence of events is/may be redundant and/or not needed, but it works for me, in a small test case. I will do some more testing and getting back to you. So far the instruments are working correctly, without errors  and the 20 second timeout is not resulting in any noticeable performance degrades.  Stay tuned for further details........tada

Regards,

Kaspar