Scan from String (arg1) in TKTDS1k2K, Input parameter invalid

[Shep_Ametek]

After calibration, i am getting a error about Command Requires GPIB controller to be controller in charge, and Scan from String (arg 1) in TKTDs1K2K scalewaveformarray.vi>scope_vppmeaurement.vi

LABVIEW: An input parameter is invalid.

NI-488: Commands Requires GPIB Controller to be in charge .

This program was working before 3rd party calibrated.  Failing on first scope measurement. Passes Scope Setup.

Thanks from newbie scheduled a May Class.

Greg Shepherd

RUNNING tEST STAND & lABVIEW 8

[Adam W]

Hi,

Can you perform a basic query in MAX or get simple communication to work?  What about an Example Program in LabVIEW (Help > Find Examples)?  This KnowledgeBase has some information about System Controller and Controller in Charge which might be helpful.  Also, if you want to make your board System Controller, you can simply check a box in MAX (see attached).  It could be that whatever calibration did, it took control from your GPIB board.

What hardware are you working with and what version of the NI 488.2 driver are you using?

Hope this helps!

Adam W
Applications Engineering
National Instruments

[Shep_Ametek]

Thanks for the suggestion. I can communicate with the scopes through Standard GPIB Commands. I called Tek Support for the TDS 2014. Tek Technical Support mentioned that some GPIB Calibration Programs change GPIB Parameters like Verbose.  I found the Verbose On or Off was not the answer. Using the GPIB Header &  Set Commands, I was able to determine what was on & Off. The ultimate fix was Header On & Verbose Off. See Tek Programmer Manual using NI's Measurement & Automation to query & Send commands through GPIB.

Thanks for your help.

[dickyoung]

I realize it has been a long time since the original question on this was posted, but I ran across a similar error generated by the Scale Waveform Array block, and realized there was a mismatch between the Abbreviated commands which were being looked for by the Match String blocks and the VERBOSE versions which the TDS2014 was putting out (at that particular time).

Subsequently, I used the 2014 in another routine in which I allowed a Reset during Initialization. Over on another discussion thread, I have now learned that the Reset command (*RST) results in the conditions HEAD ON and VERB OFF by default. So the next time I invoked the Scale Waveform Array, it errored out again, since I had modified it to look for the longer commands, but they were now coming out Abbreviated. (Arrgh !)

I found a solution. However, to do so, I had to abandon a "Match String" block and put a "Match Regular Expression" block in its place. Then (and only then), I can use a Regular Expression which contains an "A or B" option:

(:WFMP:XZE|:WFMPRE:XZERO) < with a space at the end, to denote end of Substring

I can now go back and build each one of the string matches to be more general, and it should work whether I have either Verbose or Abbreviated commands.

[dickyoung]

One additional note. I have not had to use Regular Expressions very much, so I'm somewhat of a novice. My FIRST attempt to match either the Verbose or Abbreviated commands from the DSO was as follows:

:WFMP.*:XZE.* $

 

In words, what I’m trying to say is, “Match any instance of “:WFMP”, followed by any number of any character, followed by “:XZE” followed by any number of any character, and ending with a Space character.”  It sure seemed like that should work...but it did not within the VI. That was when I tried other options and found the longer, "A or B" type of match would work, as described in my previous post.

This morning, a buddy sent me links to a couple of websites where you can experiment with Regular Expressions and see if your input is getting matched correctly. By using one of those tools, it appears that my initial attempt IS VALID, but yet, it didn't work within LabVIEW (8.6 for me). I have read some other posts RE: "Bugs" within the way LabVIEW works with Regular Expressions, so maybe this is something similar. But at least I'm up and running by using the long-way.