635 help for LabView Visa comm


New member

I have been trying to comm with a 635LCD thru Labview Visa with very limited results. I am using the virtual comm port which has been validated at 115Kbaud.
I have tried the WinTest and watched the packets but can not enter them as text in the same way in LabView. Can anyone tell me a literal text or hex command to send to it such as ClearDisplay? If I can see how it is done I am sure I can figure out the rest.:(

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I'm not familiar with Labview VISA, but I took a quick look at the Google hits. It seems like you would need a library or driver that knows how to handle the packet protocol for the 635, including calculating the CRC for each command. I have no idea whether such a driver is available.

For "canned" commands, you could get by with a static block of bytes that has the CRC included, but for "dynamic" commands where the data is variable, the CRC would have to be calculated on the fly.


New member
I can do a CRC-16 on the fly but the VI I found that does it does not agree with what I see WInTEst putting out. That's why I need to see one "literal" hex command so that I can deconstruct it. There is CRC-16 and CRC-CTTT and another question of how much to put thru the CRC at one time. The entire string is what the manual says but when I do that I get a different CRC than WinTest.

Thanks, Barry
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