visa warning 1073676294

[jamesz]

I am using LabVIEW 6.02. on a windows 98 se system.
I have a series of visa reads and writes VI’s intermixed, for controlling a special device via serial commands.
I have started getting the VISA warning 1073676294
(which I know is not an error) but it causes the next VISA WRITE(‘s) in the chain to
act as a error was generated and not send any data to the device.

If I unwire all the ERROR interconnects between the reads VI’s and write VI’s, my system will work jest fine.

If I rewire the error wires and any read generates the warring code, the following writes stop sending there data, until the warning is canceled by another read function and my system

Please help

[Shruti T]

Hi,

I found the following knowledgebase. Take a look at it.
http://digital.ni.com/public.nsf/3efedde4322fef19862567740067f3cc/c96c84c922dc3f978625632500482f78?OpenDocument

Hope this helps you.

Good Luck!
Shruti T
National Instruments

[jamesz]

Yes I also found that answer in the knowledgebase.
However Once I get the "WARNING" the VISA write VI's
will no longer send any data. IF a read VI rewurns with no errore and no warnings then the write VI's
start working.
THe Warning is affecting the operation of the LabVIEW 6.02 code.
The only work arounds I have is to either NOT use the ERROR coding or to chech the output of each READ to see if the Warning has been generated and then set the numeric code to "0". By doing either of these ALL my WRITES are sent. NOTE that the system can have as many as 2 million writes and reads. The overhead takes a lot of time.

[Dennis_Knutson]

I get the warning all of the time and it never stops subsequent writes. What is the error code that the VISA write returns? Is there the possiblity that the serial buffer still has characters in it? Have you tried doing a flush buffer before the write to see if that makes a difference.

[jamesz]

I have never seen an error from the VISA WRITE
I have connected the serial port to a RS232 diagnostic test bed that I have borrowed,
I told the test bed to expect 20 writes over the serial line and to “ECHO” back each write.
The system will stop after it reaches 20 reads.
I have put the VISA Write/Reads in a loop and send them out 20 times, with a 50ms wait between each one ad 9600 baud. I write out a number (binary) from 1 to 20
IF I do not get the warning from the VISA READ the process will work with out a problem, HOWEVER if a warning is generated the next write is skipped, and the RS232 test bed will be waiting for the missing writes even though the LabVIEW code has finished.

[Randy_H]

James,

The code itself does not matter to error checking, it is the boolean part of the cluster. If the boolean is true, then an error has occurred. I would do some highlight execution and see where that boolean goes true. It may be going true on a write or read just before your warning and since the warning does not change the value of the boolean, it is staying true, meaning an error.

Randy Hoskin
Applications Engineer
National Instruments
http://www.ni.com/ask

[PeterOSU]

I was having this same sort of problem. In my read VI I had a loop that waited for bytes to arrive at the port. The loop would end if the correct number of bytes arrived or if an error had been generated. The problem was that I was checking for an error code not equal to zero. So when a warning code was generated the loop would end before any bytes had arrived. Then when my VI went to read the port, there was no information. Once I changed the loop to check for a negative error code it worked fine.

An interesting thing about this problem is that you don't see it when you highlight execution because the bytes have time to arrive at the port before the error code check occurs.

[jake2003]

Hi,

I'm trying to communicate through the serial port to my Keithley 6487 from my PC and I receive the following:

-1073807339 (Timeout expired before operation completed)

When using a constant number within “byte count” , and this occurs regardless of the size of “byte count”

Or I get:-

1073676294 (a warning saying that “The Number of Bytes Transferred = Input Count.”)

When I use a property node.

I just can’t get data read from the serial port --

Thanks for any help,

Paul

P.s. my code:

http://www.ee.ucl.ac.uk/~pfrench/Download/Misc2.html