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Sillicon Labs UART USB Communication with LabVIEW..

I'm not sure what the problem could be. I've used in the past USB to RS-232 interfaces that used this chip and was able to use them through VISA quite easily. The only problem I had was when moving the software to Linux RT cRIOs where I had to modify the permissions on the driver entries in order to have it accessible from the LabVIEW application. Under Windows it simply worked.

Rolf Kalbermatter
My Blog
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Message 11 of 26
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We have a computer in our lab that for some reason will only communicate with our UART device on COM9, even though it shows up just fine in the Device Manager.  It's a mystery to me.

 

Similarly, we've had other devices (that did not use VISA) that wouldn't work if the port was too high for some reason.  Probably the DLLs couldn't handle 2 digits in the COM number. 

 

All this to say, perhaps try a different COM port.

--
Tim Elsey
Certified LabVIEW Architect
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Message 12 of 26
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Hi Rolf,

I'm having similar issues and wanted to ping on this thread.

I can sometimes get data from a visa read command but it varies in how many bytes before it dies, throws an error.

I"ve attached a jpeg of NI I/O Trace, the successful query is from NI-MAX which is the 2nd attached photo.

My Visa read keeps throwing an error though it seems fin in MAX. 

 

Any thoughts?

Thanks,

 

Jim

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Message 13 of 26
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Rolf, 

I realize this is an old thread but can you expound on what you had to do with the permissions in order to use VISA on a RT Linux cRIO? I am going to be working with an external Xilinx FPGA board that has a CP2108 chip on it that we'll be trying to communicate with and I'm swamped with research into how to get this to work already. Is there a specific dll I should load onto the cRIO that will make this work?

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Message 14 of 26
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First, what cRIO are we talking about? If it is not one with NI Linux RT, you can stop your research right now. There is no way to get it to work (without digging into device driver development for the old and long obsolete Pharlap ETS and VXWorks OSes).

 

Second, what LabVIEW version will that be in? LabVIEW 2014 to maybe 2016 or so had some default settings in the installed NI Linux RT image that let the virtual serial port drivers not work correctly. But if you work with a more recent LabVIEW version such as 2020 or newer, the standard settings should work out of the box. I have no recent experience with the CP2108 chip for these but adapters with the FTDI chip simply work.

Rolf Kalbermatter
My Blog
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Message 15 of 26
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cRIO-9035 with Linux RT. 

Labview 2020.

Sounds like I shouldn't have any issues then? 

Thanks for your reply!

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Message 16 of 26
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Hello everyone,

I am trying to communicate with CP2102N QFN28 using LabVIEW 2022 64-bit, but I hadn't had any luck so far with the dll export... Does anyone happen to have some working LabVIEW Library in the end?

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Message 17 of 26
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What are you trying to do? Why are you not using the VCP driver which will install the device as a normal COM port in your system that you then simply can use through VISA?

Rolf Kalbermatter
My Blog
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Message 18 of 26
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Hello everyone,

 

I also have a little problem with the "Silicon Labs CP210x" UART.

If I open the port in Putty, everything works perfectly, but in labview using these settings, unfortunately, it doesn't want to work, only an incomprehensible character reads from the port (see attached image).

Does anyone have any ideas?

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Message 19 of 26
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You should really NEVER use Bytes at Serial Port for anything but to check if there are any bytes available. Never ever (there are exceptions but they only apply to very special advanced protocol handling situations) connect that value to the VISA Read function. Your device seems to nicely output line terminated text, so use the termination character feature of LabVIEW VISA (which you do) but you need to make sure your device sends actually the carriage return (0x13) character and not maybe just the line feed (0x10). Then wire 100 or more to the VISA Read input.

 

Then right click on your read buffer control and select '\' Code Display mode. My guess is that your device sends a prompt character and expects some entry such as a carriage return or line feed before it starts to spew its non-stop data. What do you do initially in putty after opening the connection? Pressing the enter key?

 

 

Rolf Kalbermatter
My Blog
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Message 20 of 26
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