I'm connecting to a Rigol DZ1000 Oscilloscope via USB and using the :DISP:DATA? ON,0,PNG command to grab a screenshot. Reading out the data in blocks of 65535 bytes until there is no more (see attached vi).
This normally works fine but yesterday I was getting a timeout error. I fired up IO Trace and got this:
> 783. viRead (USB0::0x1AB1::0x04CE::DS1ZA201305475::INSTR (0x00000001), "#9000045852‰PNG.......", 65536 (0x10000), 45864 (0xB328)) > Process ID: 0x000039C8 Thread ID: 0x00001760 > Start Time: 13:13:54.1169 Call Duration 00:00:10.4323 > Status: 0xBFFF0015 (VI_ERROR_TMO) You can see that 45864 bytes were received, which is exactly what was specified by the binary data header (45852 data bytes + 11 header bytes + 1 termination char)
I dumped the reply string into a binary file and set the scope to run so it show something else on the screen. Sure enough the error went away. I also dumped a good result into a file. Then I tried to figure out what the problem may have been but I didn't get anywhere. Any ideas? Sure looks like a bug in VISA read or perhaps an incorrectly escaped reply from the scope?
It's very easy to "convert" the reply into the screenshot - just remove the leading 15 bytes (4 bytes from WriteBinayFile and 11 bytes from the scope header). And yes, both data files display just fine as PNG. I don't think PNG does internal checksum so byte errors would be hard to spot.
Any ideas what could have caused that timeout?
I am experiencing numerous VISA Lock Errors (-1073807345) on resources I haven't explicitly locked. This is happening on TCPIP connections to keysight N6700 power supplies and keysight N5242 PNA fairly regularly.
I have simultaneous loops in the application communicating to the different instruments, using a sequencer of sorts to pipe commands one at a time to each of my various loops.
Has anyone seen the locking error pop before while not actually using the Lock and Unlock VIs? This issue has gotten worse lately and it has come time to find the root cause. My only thoughts are that it may have something to do with having NI MAX and Keysight Connection Expert both installed and possibly trying to "ping" these devices. Every once in a while me sending commands and these "pings" may clash and cause the locking error.
Error reads as follows:
"Specified type of lock cannot be obtained, or specified operation cannot be performed, because the resource is locked. VISA error code -1073807345 (0xBFFF000F)"
We are using LabVIEW 2013
Thanks in advance!
Can you take a look at this?
The only work around I found is to dynamically open the connection with an external VI to make it fail so the second time it works.
If anyone has an instrument that communicate trough TCP-IP with VI, please try on your side with LabVIEW 2018 and visa 18.
By Óscar Gómez
In a few days my team and me will start a project and I'm a little anxious because I've never work with PXI Systems... If anyone want to tell me a tip, recommendation or something about your experience with this systems, you'll welcome. I'm one of the developers in the crew!.
I've experience with cRIO and cDAQ.