Visa read over USB error -1073807313

[StevenD]

Hello all,

I have an application where I am trying to get resistance data from a Keysight E4980. I have done this in the past over Ethernet and Visa read/write. I would like to change the connection to USB and after doing so most things still work. However when I try to read the measurement I get error -1073807313 at the Visa read. If I switch to Ethernet I don't get this error and on USB all the other commands work (IE I can set the frequency and voltage level and read the error status.) The only difference I can see is that when I read the measurement data I try to read 512 bytes, when checking the error status I read 256. Is there some configuration setting I need to set to enable me to read more than 256 bytes over USB?

[patrick.o]

StevenD,

Do you know the class of your USB device (USBTMC vs USB RAW)?

I have attached one of our KnowledgeBase articles below which covers this topic in detail and may be of use.

Using NI-VISA to Communicate with Your USB Device

http://zone.ni.com/reference/en-XX/help/370131S-01/ni-visa/usingnivisatocommunicatewithyourusbdevice...

Please let me know if this helps!

[StevenD]

The manual says

USB interface port
Universal serial bus jack, type mini-B (4 contact positions); complies with
USBTMC-USB488 and USB 2.0; female; for connection to the external controller.
USBTMC: Abbreviation for USB Test & Measurement Class

I am going though a USB hub, but I don't know why that would make a difference. 

[StevenD · Accepted solution]

Just to complete this thread -

I opened a ticket with NI and they suggested changing the VISA read/write functions to be synchronously executed and this seems to resolved the issue. Not sure why this was a USB specific problem but I have not seen any errors since changing.

[lorymecs]

Could you elaborate on "synchronously execute"? I am having similar issues as you. 

[RavensFan]

Right click on the VISA Read or Write.  Synchronous I/O Mode