Error 1073807298 on VISA write

[DPS]

Thanks - I'd be interested to hear how you get on. Sadly this job has now passed out of my hands with this problem unresolved, but as I said, it seems to work happily enough. Would be nice to know what was going on though for future reference.

[Jim West]

I put out a call on info-labview for USB<>Serial support and Non-support. I have received some replies. I will summarize there and here later this week.

Jim

[Jim West]

Here is the summary I promised from info-labview responses..

OK with XP SP2 and WIN2K SP4. I have tested the Belkin with 3.3 and 3.2F1 VISA.

The Belkin F5U109 available at Circuit City.

The Keyspan USA-19HS available at Comp USA.


OK with XP SP2
Inside/Out networks Edgeport 8 USB to RS232


OK with W2K and W98
Moxa C320PCI



OK with W98
KeySpan



Needed to download driver update but then OK – No note on OS
Quatech USB to serial 4 port device

Not OK with MAC OS 10.3.5
http://sewelldirect.com/usbadapters


OK with MAC OS 10.3.5
Keyspan


I also got the following from an NI source. He said that several devices that NI has tested that were not compatible with VISA didn’t perform the Windows flush command correctly.

+++++

In order to work around a serial device that doesn't support the Windows flush command try inserting a VISA Set I/O Buffer Size VI directly after the VISA Open for any COM port. Please make sure that you set the mask to 48 and the size to at least 4k or the maximum number of bytes that you will ever write or read. That should cause the VISA Writes to not call the Windows flush command and allow the writes to execute without problems if my assumptions are correct.

+++++



Jim West
Senior Software Engineer
Summitek Instruments
303-768-8080
jwest@summitekinstruments.com

[pippo maremco]

I was experiencing the error - 1073807298 when using VISA write command with the USB to UART bridge  Silicon -CP 2102

I've just tried Jim West solution (inserting a VISA Set I/O Buffer Size VI after the VISA Open) and  the result is very good.

Thanks

[Jore]

Hi,

I had the same problem with Advantech's ADAM-4570W. I solved the problem with VISA Set I/O Buffer Size. Just adding the VI before the write command and defining mask to 32 (so it is write buffer). Other parameters I kept as default.

And Jim West, thanks! Your reply was helpful.

[Kikanaide]

Just another confirmation - as pippo maremco has said, Jim West's solution appears to work quite well with the SiLabs CP2102 USB-UART bridge.

[shoneill]

I was having the same problem with a MOXA Nport 1240, but the set buffer trick seems to keep the program happy (most of the time at least).

I'm surprised, because I always had the impression that MOXA made solid products.

I have also used the edgeware adapter in the past (It was in a previous job, and I'd been racking my brains trying to remember which make it was).  Had no problems whatsoever with that one.

I think I'll buy another.

Thanks

Shane.

[Fantester]

Does anyone know if the work arround slows the data transfer rate?

[JoshuaP]

Actually, it should speed it up or at least speed up the application to a point. Setting the buffers prevents the flush command from executing automatically. The result is that the VI's move on much quicker and do not block, because they are not waiting for the data to be sent. The only real down side is that after the write command finishes, don't expect all of the data to have been sent out the port yet. Some of the data may still be transfering through the buffers to the hardware.

Typically, setting the buffers is actually a really good thing to do. It allows your application to send the data to a buffer that will be used behind the scenes to stream out the data to the port as fast as the port can send it. This gives your application a chance to process other data or get the next packet ready to transfer. I'm not a fan of making my application wait on a slow serial port.

In the NI-VISA Help there is a great section called "Controlling the Serial I/O Buffers" that talks about this in a little more detail and it links to a few other good documents on this topic of setting and flushing buffers.

-Josh

Message Edited by JoshuaP on 09-29-2006 08:11 AM

[Schwede]

Hello,

i can`t solve the problem with the buffer solution. Can someone send or post an example code??
I trie to test an USB to serial adapter. USB is COM4 and the serial port is COM2. Now i want to send some data from COM4
to COM2.

Can somebody help me?

thanks schwede