Access violation when calling ul.stop_background

[mccdaq]

Access violation when calling ul.stop_background

[jeffreyg3]

Hi,
We have run your app twice to completion with no failures.

[willyd]

@jeffreyg3 Thanks for the quick reply as always. Could you please paste the output you get here? The program crashes silently so it might not be obvious that it crashed. With default arguments it should do 1000 iterations. So if it did not crash, you should see something like this at the end:

999| 0.00: status = 1, curr_count = 00015, curr_index = 014,  arr[014:015] = [12.9937604]
Sleeping for 0.0 secs before stop
Stopping background function, status was 1
Background function stopped
Freeing handle 2072774443008
Handle freed
Releasing device 0
Device released 0
Polling done.
Program exited normally.

But on my side it never does. It always ends with something like:

4| 0.23: status = 1, curr_count = 00065, curr_index = 064,  arr[064:065] = [12.97624382]
4| 0.12: status = 1, curr_count = 00070, curr_index = 069,  arr[069:070] = [12.88793211]
4| 0.02: status = 1, curr_count = 00075, curr_index = 074,  arr[074:075] = [12.88271523]
Sleeping for 0.0 secs before stop
Stopping background function, status was 1
Background function stopped
Freeing handle 2072774443008
Handle freed
Releasing device 0
Device released 0
Polling done.
Creating device
Device created
Configuring channels...
Starting background function...
Background function started with rate 50
Polling for 0.3734027203051207 secs...
5| 0.37: status = 1, curr_count = 00000, curr_index = -01,  arr[-01:000] = []
5| 0.27: status = 1, curr_count = 00005, curr_index = 004,  arr[004:005] = [12.98928908]
5| 0.17: status = 1, curr_count = 00010, curr_index = 009,  arr[009:010] = [12.90359038]
5| 0.07: status = 1, curr_count = 00015, curr_index = 014,  arr[014:015] = [12.9937604]
Sleeping for 0.0 secs before stop
Stopping background function, status was 1

Which is the print statement just before the call to ul.stop_background. Which I believe crashes the whole program.

Just to make sure, did you test with a USB2404-UI?

[jeffreyg3]

When you originally sent this request we did run it for 1000 iterations.
We reduced the iterations to 100 and sent the output to the attached file. The results show that the program exited normally.
test.txt

[willyd]

@jeffreyg3 Thanks for the repy. Interesting. In most cases it crashes well before 100 iterations. However I was able to run it for more than 100 iterations a few times.

What device did you use? What Python version? What is your cbw64.dll version or Universal Library version (I am not sure how to determine which version I have).?

[jeffreyg3]

text2.txt
Used a USB-2404UI
version of cbw64 was included in InstaCal 6.72 (part of the mccdaq.exe download)
python 3.8.5

To determine the version of InstaCal/UL, run InstaCal, and click on Help >> about Instacal.

[willyd]

@jeffreyg3 Thanks.

I thought this could be a Python version issue so I made C/C++ version of the provided script and it still crashes at the same point.

Could this be a firmware issue? Is there anyway I can get the firmware version of my board? There does not seem to be a firmware update for this board here: https://www.mccdaq.com/firmware.aspx.

main.cpp.txt

[jeffreyg3]

There is no firmware upgrade for the USB-2404-UI

Unfortunately, we cannot duplicate what you are seeing. Your program works on our Windows 10 system, running Python 3.8.5, and InstaCal 6.72.