Getting error when running with custom firmware on pico with labview

This is failing in the init code, so it’s not even reaching your code.  One of the installed tools with LabVIEW is NI I/O Trace.  Run that, turn on tracing, then run the VI again and see if that gives you a clue to what is happening.  Also, don’t be afraid of putting a breakpoint on a wire and turning on the lightbulb, then single stepping though the code, probing wires to see values.  Sorry, I’m not at home right now so I’m talking from memory rather than with LabVIEW in front of me.

I have seen his problem myself: the SCPI ID command would work with NI Visa Interactive Panel but not with my own Visa write.  Turned out that the string command I was sending, “*IDN?\n” was treating the “\n” as two characters and not a control character (new line).  The fix was to right click the string constant and make sure the “display \ codes” option was selected.

The init block indeed checks for the IDN* string

I haven't exposed the connectors to the button that can turn ID Check off.

You can do this yourself, by clicking on the connector location in the Icon, then selecting the control

If you write firmware with a different ID string, you should also create a driver and  adapt that Init block to your ID:

I'll take care that the PST driver is updated to exposes these 2 connecters (set as  optional):

other warning: that LED is used by the USB code. To provide feedback as prescribed by USB standard.

HI Andrew J Jan Cumps , I checked the string constants inside the init block, the "display \ codes" option is checked. Then I tried turning off the ID query for the init block, this time I didn't face the issue. After running with "Step over subVI", it seems the issue occured after the read operation for ID. In the probe watch window, in the possible reason section, it is written "VISA:  (Hex 0xBFFF0015) Timeout expired before operation completed." One more thing, I am getting this error only on alternate runs and that too only in my custom VI. Other example VI's are working fine.

If you look at the comment in the code it says to ignore the timeout and the error code is the same as the one in the probe.  I don’t know why this happens really - Jan has given a hint but it’s not something I’ve seen - but that error should get removed and the VI complete successfully.  Is there a value on the bytes read wire.  Also, use NI I/O Trace to get an idea of what is going on.

I had to pop out, but looking a bit further.  Your first error you reported was the other one shown in this VI, 1074003951, which implies that the timeout error is being swallowed (check the output wire of the clean error VI that is highlighted in your image.)  So what is on the wire that goes into the string comparison from the VI Read and the Constant PICO-PI,LABTOOL.  Try probing further through that VI execution but please do try NI I/O Trace to see what it says.

I also can't unfortunately help unless I can see the SCPI commands (which I believe that NI I/O trace will provide).

Do you have a github repo of your firmware?

cbohra00627 said:

One more thing, I am getting this error only on alternate runs

When you first run an existing example,

does your flow then:

• fail at your first run after that or
• fail during the second run?

Yes. We'll not be able to solve this by looking at screenprints.