VISA Read over USB Problem: After a while the xBFFF0015 Timeout Error occurred

[johndoe_666]

Hi,

I have trouble using labview with my non-NI USB device:

The device is an analog input DAQ board. I was able to setup communication with the board using a VISA driver specifically created for this board and direct FW calls using the product's firmware specification provided by the manufacturer.

This method has been working pretty good so far, but when I try to get large amount of data (64k samples @100ksps), the VISA Read returns the 'VISA: (Hex 0xBFFF0015) Timeout expired before operation completed.' error.

Please see the attached screenshot of the block diagram for details.

First, an 'analog input scan start' command is sent to the DAQ device, and then the vi tries to read all collected data from the device, once the right amount of data retrieved, or no more data is available the data collecting process (the while loop) ends and an 'analog input scan stop' command is sent to the DAQ device.

The data collection starts with no problem, but after a while, in loop# 400, the VISA Read hangs and then returns the error mentioned above.

I tried to increase the time out value, but it didn't help, the error occurred after the same number of loops, the VISA Read got hosed and the error occurred after the longer timeout expired.

I also tried to add some delays in the loop, but it didn't help either.

I am not sure what do I miss here and I would highly appreciate if anyone could give me some guidance how to solve this issue.

Thanks,

John

[Dennis_Knutson]

You've got a non-NI device from a vendor that you won't name, code from that same vendor, and all that you provide is a picture. Exactly what sort of help do you think someone can provide? What does the vendor say?

[johndoe_666]

I just wanted to specify that this is not an NI board avoiding to make people think this is a hardware issue. And I think that the rest of the code is irrelevant in this case.

I believe that I don't use the VISA functions correctly. I assumed that someone who used these functions before would be able to point out the obvious steps missing in the data collecting process using the VISA functions.

[Dennis_Knutson]

You said you got the custom VISA driver and code from the vendor. Reading and writing to a USB device with such a driver is unique to that specific device. You cannot really expect help if you don't provide any details.

It is almost always a major mistake to throw away a driver that a vendor provides and create your own VISA driver. The only ' standard' VISA drivers are for USBTMC and RS-232 connections.

[Dennis_Knutson]

To be extra clear, you say everything is based on the vendor's firmware spec. Your strange read in. the while loop would be based on that, presumably. Yet you don't attach the spec to ask to see if you've read it correctly.