Data Display on HP 54504a Scope

[nyc_(is_out_of_here)]

One thing unrelated that I see in your VI, is that following a *RST, you are not waiting.

This process sometimes can take a few seconds with an instrument.

The :MEAS:VBAS is only a command to make a measurement.

If you push the front panel button to make the same measurement, does that value display?

[Xsis]

We are using :meas:vbas? as our program line to tell the scope to measure the VBase and send it to Labview.  Apparently the VBase measurement is getting sent to Labview but it just isn't getting sent to the front panel.  In highlight execution mode the value for VBase is shown on the block diagram when I run the VI, but it does not display on the front panel. 

I don't think it needs a delay added.  The measurements and settings for the scope seem  to be working fine.  Maybe there is some kind of formatting for the VBase indicator box that we don't know about?

[JÞB]

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@Xsis wrote:

We are using :meas:vbas? as our program line to tell the scope to measure the VBase and send it to Labview.  Apparently the VBase measurement is getting sent to Labview but it just isn't getting sent to the front panel.  In highlight execution mode the value for VBase is shown on the block diagram when I run the VI, but it does not display on the front panel. 

I don't think it needs a delay added.  The measurements and settings for the scope seem  to be working fine.  Maybe there is some kind of formatting for the VBase indicator box that we don't know about?

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AH HAH! the magic 8 ball says

"Your response contains a linefeed and the indicator is not showing the line the text is on." try a "Trim Whitespace"

[Xsis]

I am not familiar with the "trim whitespace" function.  What menu is it in or what command do I need to use?

[Xsis]

Thank you Jeff!  We found the trim whitespace box and with it inserted the VI displays the VBase now.  I guess all we were seeing before was whitespace in front of the number and now that is gone.

Brian

[JÞB]

Glad to have helped (Go ahead and mark the post a solution so others can benefit as well)

That scope seems to send a <CR/LF> (Carrage return + Linefeed) at the end of each message so if you continue to read only the expected 12 bits you will leave those characters in the buffer an they will stay there until the next time you read and be prepended to what you expect (so youll miss the last two characters!

To avoid this set the Start Boolen TRUE (you have it wired to serial initialize at Enable Term Char)  leave the default termination char 0x0A (Linefeed) and read 100 characters (Some number MORE than you expect in the response).  VISA is smart that way and will read all characters from the device until an linefeed is seen, 100 characters are read or the timeout expires.  In that Mode each query will cause the device to respond with 1 message and the read will read the entire message leaving nothing in the buffer.